Tag Archives: Clean Rooms

By George Miller

The recent passage of an international standard for particle-counter calibration–ISO 21501-4–is having a ripple effect among contamination control practitioners: Suppliers who make particle counters are ensuring standards compliance in their products; the promulgators of recommended practices are working to ensure that existing practices align with the new standard; and manufacturers who use ultra-clean rooms, especially those in regulated industries, are considering how–and how quickly–to bring existing operations into compliance.

Among those in the first category is Hach Ultra (Grants Pass, OR), which announced in August the MET ONE 7000 series remote air particle counters that meet ISO 21501-4 requirements.

The standard updates and supersedes an existing Japanese spec, JIS B 9921, as well as an ASTM International standard practice for calibration of airborne particle counters.

Metrology and calibration details

“The new standard is similar to the Japanese standard that we’ve been using for some time,” says Jerry Szpak, director for research and development at Hach Ultra. “But it has made some steps in illuminating details on metrology and calibration.” (See “Achieving Particle Counting Accuracy,” CleanRooms, p. 36, July 2008.)

He adds that the new standard and the existing Recommended Practice from the Institute of Environmental Sciences and Technology (IEST-RP-CC014.1, Calibration and Characterization of Optical Airborne Particle Counters) are somewhat different in terms of resolution and maximum particle concentration specifications. Szpak says the Recommended Practice should be revised to comply with ISO 21501-4.


Software upgrades and changes to calibration processes and procedures differentiate the ISO-21501-4-compliant MET ONE 7000 series from earlier Hach Ultra particle counters. Photo courtesy of Hach Ultra.
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Recommended Practices (RPs) are usually developed in the absence of a standard. In fact, they are often used when standards are being developed, according to David L. Chandler, chairman of the IEST CC014.1 Working Group and engineering manager at Climet Instruments Co. (Redlands, CA).

“Both the Japanese and ISO standards include acceptance criteria, whereas the RP contains procedural information. That’s where they differ,” says Chandler. “The RP’s two sections on counting efficiency, for example, run five pages, covering primary and secondary methods. The ISO standard has just five sentences on the same topic, plus a one-page annex.”

As far as aligning with the existing standard, the ISO standard contains a response-rate spec–how fast the instrument responds to changes in particle concentration, Chandler says. The RP includes nothing about that. ISO also covers size settings, while the RP does not.

Filling the gaps

“So we’ve identified these areas that have now become standardized and that could benefit from procedural details. We’re currently working to fill those gaps,” says Chandler.

Among the more important aspects of the new standard, according to Chandler, is that it states that the calibration at every interval should include size calibration, size resolution, and counting efficiency verification. “This is a big deal if a customer’s current equipment cannot meet that standard,” he says.

He adds that Climet particle counters, which have long included counting efficiency verification on calibration certificates, already comply with the new standard. “That comes standard with the purchase of a new unit and is available for subsequent factory calibrations. It is a new thing for field calibrations,” notes Chandler.

Regarding customers, Chandler says he is unsure how quickly users will have to make changes to particle counters already in use. “It depends on how strongly they enforce the standard,” he says. “Companies overseen by regulators would probably have to comply more quickly than companies in an unregulated environment, who use counters to improve their manufacturing yield.”

FDA drives move to remote units

Matt Smith, Hach Ultra marketing manager for life sciences, identifies the U.S. Food and Drug Administration among regulators having the greatest impact, based on the increased scrutiny of manufacturing processes it is requiring of drug and medical device makers. “As life sciences companies push into continuous monitoring, more of them want to change from portable particle counters to permanent remote ones,” he says.

“Life sciences regulatory requirements dictate that when product can be exposed, you have to use particle counters within one foot of the activity. We get in very close to filling operations. The particle counters are now easy to swap out. ISO 21501-4 makes them perfectly interchangeable.”

One design goal behind the MET ONE 7000 was to be able to retrofit existing cleanrooms without having to break their integrity. “Everything is built in,” says Smith.

R&D director Szpak says that the MET ONE 7000 instruments include upgrades to the company’s proprietary Core Cal software and changes in its procedure philosophy. That philosophy now encompasses “the calibration process and procedures put in place to meet the intent of ISO, including which tasks are performed by the factory, which are performed by service people, and which by calibrators,” says Phil Ammon, product manager for service. The software and procedure changes differentiate the MET ONE 7000 from the company’s previous particle counters, he says.

Yet all is not lost for earlier instruments already in use. The software provides the means to make the company’s 3400 series particle counters forward compatible. Those instruments can be recalibrated to meet the ISO standard and bring them up to compliance.

Particles


September 1, 2008

compiled by Carrie Meadows

Entegris to acquire Poco Graphite

Purification and chemical transport equipment supplier Entegris has signed a definitive agreement to acquire privately held Poco Graphite, a manufacturer and marketer of specialty graphite, silicon carbide, and other advanced materials, in an all-cash transaction valued at $158 million. Based in Decatur, TX, Poco provides process-critical graphite-based consumables and finished products used in semiconductor, electrical discharge machining (EDM), medical, optoelectronic, aerospace, and specialty industrial markets. According to Entegris, the transaction is expected to enhance the company’s semiconductor market position as a provider of process-critical consumables and related products and services, and will enable its growth in other high-performance industries.

Mallinckrodt Baker doubles solar-cell cleaner production capacity

Mallinckrodt Baker, which manufactures high-purity chemicals and related products and services, plans to double manufacturing capacity for its BakerClean PV-160 solar cell surface cleaners to meet growing demand from solar cell manufacturers. As part of the capacity expansion, Mallinckrodt Baker will begin manufacturing the equipment in its high-volume facility in Paris, KY, while increasing existing manufacturing capacity at its facility in Deventer, the Netherlands. In addition to expanding overall production capacity, the company says the decision to produce the surface-cleaning tool in both the U.S. and Europe reduces the supply chain risk for its customers, since many manufacturers require backup sources of supply. Mallinckrodt Baker believes its two geographically distinct manufacturing facilities meet the dual-source requirements common in the PV industry.

Where are the cleanrooms?


September 1, 2008

Defining and calculating the number of active cleanrooms worldwide poses a challenge.

By Robert McIlvaine, The McIlvaine Co.

The cleanroom business is unique in that it is not structured around one industry or one product. It is structured around a result. However, this result is even subject to various definitions. Historically the definition has been based on enclosed space that contained recirculating air with fewer particles than found in the normal environment.

Typically this space utilized at least partial filtration with high efficiency (HEPA) filters. However, providers of gloves, garments, and other supplies have found that there is a significant market for space that strives to be cleaner than the typical office but would not meet the conventional cleanroom class limitations.

In November 2001 the U.S. Federal Standard 209E was canceled by the General Services Administration and replaced by ISO standards. This older standard defined the cleanest cleanroom as having no more than 1 particle per cubic foot, which was larger than 0.5 μm. The ISO standards set up three classes of very clean rooms to replace the Class 1 rooms under FED-STD-209E. They are based on the numbers of particles larger than 0.1 μm.

One micrometer (micron) equals 1,000 nanometers. The measurement of 0.1 μm, which is now the new criterion for measuring the cleanliness of space, is equal to 100 nm. Let’s assume that you start up a business to produce nanoparticles 50 nm in diameter. Lots of these particles may escape into the room. But since the cleanliness definition is based on a minimum particle size that is twice as large as particles you are manufacturing, you could theoretically meet the ultimate cleanliness criterion of ISO Class 1.

This inability to measure very small particles is of concern to the medical community. There is the realization that these nanoparticles can easily penetrate the lungs and reach the bloodstream. Therefore this progress in technology will put pressure on the cleanroom industry to once again revise its basis for classification.

The old Class 100,000 room (now ISO Class 8) was based on not exceeding 100,000 particles larger than 0.5 μm. There was no “less clean” classification. Now we have ISO Class 9, which allows 1 million particles/ft3 that are larger than 0.5 μm and even some particles at 1- and 5-μm sizes.

The average office building has a cleanliness level somewhere close to the ISO Class 9 limit. There are substantial purchases of garments and gloves by operators who want to maintain a space as clean as or cleaner than the typical office. In terms of floor space and numbers of workers, this is a very significant segment for the cleanroom industry.

It is not a significant segment for manufacturers of filters and air handling equipment. Most of these ISO Class 9 rooms achieve their cleanliness with little or no HEPA filtered air. But as a result of the large amount of space and number of employees, it has potential for garment and glove suppliers.

These ISO Class 9 rooms are just as often found in combination with cleaner space than as isolated operations. Many pharmaceutical companies surround their cleaner space with the relatively clean space. One of the reasons is that with movement in and out of the cleaner space, it is less likely to become contaminated if the entry space is relatively clean.

People frequently want to know how many cleanrooms there are in a particular country or a particular industry. This is another tricky question. If an operator has two ISO Class 4 cleanrooms inside an ISO Class 8 cleanroom, does this count as three cleanrooms or one?

Another factor is the number of shifts. One client needed help when his $100,000 survey did not match his knowledge of the industry. It turned out that the people doing the survey had assumed one-shift operation at all rooms. In fact, some operate three shifts and others two.

In the last several decades, concern about molecular contamination has entered the picture. Molecules of gases such as volatile organic compounds (VOCs) cause damage to computer chips and can impact health. This interest adds another complexity to the cleanroom rating system.

Numbers of cleanrooms

Despite the previous explanation as to why numbers of cleanrooms are of little value we will now attempt to calculate these numbers. The reason to do this is that the questions keep coming even when it is explained that there are lots of caveats in the statistics.

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We have calculated the number of cleanrooms in the world at approximately 121,000 (see Table 1).

This calculation does not include minienvironments or biological safety cabinets as rooms. But it does include rooms as small as 100 ft2. The average size of rooms varies greatly by industry. Aerospace has some vast cleanrooms where space shuttles are assembled. Flat-panel display rooms can be very large as well. At the other end of the spectrum are the biolab rooms that can include animal research and similar applications.

Asia boasts nearly half the cleanrooms in operation worldwide while Africa has few. Asia will continue to gain share as the electronic industry expands in this region.

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The Asian market share in terms of annual investment in new rooms is greater than 50 percent. This is an indicator of a similar trend in numbers of rooms.

Asian cleanrooms employ more than 1 million people compared to 400 million in the Americas. There are some individual cleanrooms in Asia with 9,000 workers in garments and other cleanroom clothing. There are no comparable sites in the rest of the world.

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Asia will continue to add employees and build more cleanrooms at a rate greater than the other regions. The flat-panel industry is almost exclusively located in Asia. The pharmaceutical industry is one of the few that manufactures in Europe and the United States at a greater rate than in Asia. Quality control is one of the issues that has kept the bulk of production elsewhere.

It is recommended that cleanroom space and numbers of employees be utilized in assessing markets. The number of rooms is a weaker statistic because of definition problems. The same is true of revenues. Prices in China are much lower than in the U.S., so equal revenues do not translate to an equal numbers of units. It is better to start with the number of employees and the number of garments per employee, then units can be calculated. Revenues can then be forecasted using the different prices in different regions.

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Robert McIlvaine is president and founder of The McIlvaine Co. in Northfield, IL. The company first published Cleanrooms: World Markets in 1984 and has since continued to publish market and technical information for the cleanroom industry. He can be reached at [email protected].

The nano revolution


September 1, 2008
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The number of products incorporating nanoscale materials is increasing at a rapid rate, but manufacturers are still struggling to find ways to control these materials in the production environment as they ramp up to commercial scale.

By Sarah Fister Gale

In the past few years, the nanotech revolution has gone from great ideas to commercial realization. Manufacturers across multiple industries, from pharmaceuticals and health care to coatings, semiconductors, and microelectronics, are recognizing the current and future impact nanomaterials can have on their products.

Nanomaterials offer great promise for a new generation of products because they deliver higher strength, lower weights, and more easily soluble attributes than have been previously seen in conventional materials.

“Nanotech isn’t a new market or industry–it’s an enabling technology that improves many types of products,” notes Jurron Bradley, senior analyst at Lux Research, a provider of strategic advice and intelligence for emerging technologies, based in New York. “You find it in coatings boosting the efficiency of automobile engines, in nano-enabled finishes protecting electronic devices, and nanoparticulate reformulations that make cholesterol-reducing drugs more effective. These innovations aren’t always visible to consumers, but they improve products and boost margins. That’s why nanomaterials use is only going to keep growing.”

The market has seen recent rapid growth, with great expectations for the near future, says Bradley. In its recently released report, “Nanomaterials State of the Market Q3 2008: Stealth Success, Broad Impact,” Lux estimates that nanotechnology was incorporated into $1.4 trillion worth of products in 2007, up from $497 billion in 2004, representing a compound annual growth rate of 41%. The research firm expects this figure to grow at a compound annual growth rate of 14% through 2015, climbing to $4.0 trillion worth of manufactured goods in that year.

The report notes that established nanotechnology–which includes nanoscale objects and devices based on long-known processes and technologies, such as semiconductor chips with nanometer features and nanoscale particles such as carbon black–dominates the current market, accounting for $1.3 trillion of the $1.4 trillion in nano-enabled manufacturing output in 2007. By 2015, Lux expects emerging nanotech–novel materials currently under development–to take center stage, accounting for $3.1 trillion of the $4.0 trillion in output.

The materials and manufacturing sector saw the greatest impact as nanotech made its way into intermediates like coatings and composites for products like automobiles and buildings; electronics followed at $35 billion from emerging nanotech applications in fields like displays and batteries, while health care trailed with $15 billion in revenue, driven by pharmaceutical applications.

“We are seeing a lot of growth in the electronics and IT sectors,” Bradley says. “Manufacturers still have to prove the technology is viable, but they are seeing much greater acceptance.”


Figure 1. An atomic force microscope (AFM) image of Unidym carbon nanotubes (CNTs) on a substrate. Photo courtesy of Unidym Inc.
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That acceptance is coming after years of trial and error among researchers on how to scale up from the lab to a volume manufacturing facility. From managing human health and safety issues and designing air handling and filtration systems that can manage nanoscale particles, to controlling the way materials are introduced into the environment, processed, and removed, manufacturers are being forced to re-evaluate all of their contamination control processes for the nanoscale.

But is it safe?

A flurry of attention-grabbing research reports and studies warning of the dangers of nanomaterials from special interests groups, such as the Project on Emerging Nanotechnologies and Friends of the Earth, have gained much media attention over the past couple of years, inciting fears among consumers about risky nanomaterials in their products and demanding caution from manufacturers unsure about whether to risk using a product that has potentially or perceived harmful consequences. Even as these materials are proved safe, public perception of risks can have lingering negative effects on marketability, particularly for products sold directly to consumers.

“There is still a lot of concern about nanoparticles,” notes Harry Way, technical director of Netzsch Fine Particle Technologies, a manufacturer of advanced process technology for nanomaterials based in Exton, PA. “In reality, though, we’ve all been exposed to nanoparticles for as long as we’ve been burning things.”

In spite of that statement, the use of nanomaterials in products and the accompanying concerns have made environmental and human health and safety a top priority for standards writers and special interest groups.

A report released in July 2008, “Nanotechnology Oversight: An Agenda for the New Administration,” by former Environmental Protection Agency (EPA) official J. Clarence Davies calls for greater oversight in the use of nanotech materials and defines a roadmap for the next presidential administration that includes immediate and longer-term steps to shore up what he sees as shortcomings of nanotechnology oversight.

Davies calls for the White House and federal agency policymakers to maximize the use of existing laws to improve nanotechnology oversight by defining nanomaterials as “new” substances under federal toxics and food laws, thereby enabling EPA and the Food and Drug Administration (FDA) to consider the novel qualities and effects of nanomaterials. Davies also calls for federal pesticide and workplace safety laws to be used to protect against potential adverse impacts of nanomaterials.

The report highlights the importance of creating sensible nanotechnology policies that will help ensure the safe and sustainable application of nanotechnologies to climate change, food security, water purification, health care, and other pressing global problems.

“The next presidential administration will face a host of complex policy issues concerning energy, the environment, food safety, consumer products, and the workplace,” he writes in the report. “One issue, however, that will impact virtually all of these policy areas is nanotechnology oversight.”

The National Institute for Occupational Safety and Health (NIOSH), the leading federal agency conducting research and providing guidance on the occupational safety and health implications and applications of nanotechnology, is conducting ongoing research into 10 areas of concern that it has identified for safety research regarding the use of nanomaterials. These include toxicity and dosages, fire safety, effectiveness of engineering controls, and safety of current exposure levels.

Meanwhile, many other global organizations are producing their own research and standards documents relating to nanotechnology, including the American National Standards Institute (ANSI), the Institute for Electrical and Electronics Engineers (IEEE), The British Standards Institute (BSI), and the International Organization for Standardization (ISO).

The first steps have been to create standards for measurement, nomenclature, and characterization of nanomaterials, notes Kalman Migler, in the Materials Science and Engineering Laboratory at the
National Institute of Standards and Technology (NIST), a non-regulatory federal agency that advances measurement science, standards, and technology, based in Gaithersburg, MD.

“We need to develop reference materials so that we all have the same samples to do the same tests,” he says of the need for standards concerning these issues. “Standards for nano will create immense value by bringing order and efficiency to the marketplace.”

Migler points out that in order to accurately assess the toxicology or characteristics of nanomaterials, the fundamental properties must first be agreed upon. “It creates a uniform approach and develops confidence between buyers and sellers.”

A group within IEEE, a non-profit professional association for the advancement of technology based in Piscataway, NJ, produced IEEE 1650

Chemical air filtration combined with on-site analytical evaluation of filtered area and filter solution provides cost reduction by optimizing filter lifetime.

By Jürgen M. Lobert and Joseph R. Wildgoose, Entegris, Inc

Airborne molecular contamination (AMC) control in semiconductor manufacturing process bays has historically been applied to unique problems such as unwanted doping or corrosion control on metal films. With the advent of the 65- and 45-nm technology nodes and their highly energetic ultraviolet (UV) light, the impact of AMC on exposure and metrology tool optics and photomasks has increased with decreasing exposure wavelengths. Increasing beam intensity at each node drives sensitivity to contaminants, causing issues such as yield, reduction, optics degradation, and reticle haze. As a result, AMC control has increasingly become necessary for photolithography cleanrooms, but until recently most of these chemical filtration solutions were targeted to individual tools or tool clusters.

Most new fabs are now being designed and built with provisions for using AMC filters in the ceiling grid, and existing fabs are upgrading to these filters by retrofitting air handlers. Cleanroom operators considering use of chemical HVAC filters can help optimize the chemical and physical performance by working closely with filter vendors to understand and define performance parameters and AMC reduction requirements by monitoring both over time.

One approach for such cooperation is the combination of high-performance AMC analysis to determine the cleanroom’s air chemistry and filter performance with the customization of filter media to optimize filter life, removal efficiency, and pressure drop. Off-the-shelf filtration solutions rarely satisfy AMC requirements and facility operator expectations in state-of-the-art semiconductor cleanrooms. With thousands of filters installed in modern photobays, cost reductions are becoming an integral part of semiconductor manufacturing. In addition, increasing competitive pressures require a comprehensive understanding of cleanroom AMC levels and filter performance.

Cutting-edge technology

Semiconductor processing requires UV light to create the smallest of features on silicon wafers for powerful processors and memory chips used in modern computers and consumer electronics. The latest generation of semiconductor exposure tools employs 193-nm wavelength UV lasers. The energy content of this light can easily split molecules into reactive fragments, which can trigger chemical reactions and adhere to optical surfaces that can cost as much as $5 million, as well as $10,000 per hour in downtime in cleaning or replacement. In addition, corrosion of surfaces by acidic compounds and the buildup of haze through chemical reactions, such as acid-base combinations, have always been problematic, even in older technology nodes.


Figure 1. Typical HVAC chemical filter installation in a ceiling grid. Photo courtesy of Sam Lin/Entegris.
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Traditionally, chemical filtration to remove AMC was applied through specific tool solutions such as filtration cabinets for lithography exposure tools, tool-top filters for coat/develop tracks, and a multitude of point-of-use purifiers for targeted purging of critical cavities and surfaces. With maturing technology nodes, cost reduction becomes crucial in lithography cleanroom operation. Tool operators want to extend the lifetime of costly high-end tool filters; any maintenance they have to perform causes tool downtime, a significant expense in semiconductor manufacturing. The use of HVAC filters for the entire cleanroom (Figs. 1 and 2) can prolong the life of such tool filters, cut down on maintenance, and reduce the risks involved with ambient exposure of sensitive products.

Separating the good from the bad and the ugly

There are numerous chemical air filter products on the market today, many of which claim to be high-performing and suitable for the protection of advanced semiconductor processes. However, not all product performance documentation is based on the same test conditions, making the selection of proper chemical air filters a daunting task for end users or the engineering firms hired to make such decisions. Compounding this dilemma is the lack of an industry standard for filter performance testing that would aid end users in the selection of a system best tailored to meet their needs.


Figure 2. Typical two-layer HVAC chemical filter for comprehensive removal of acids, bases, and organic AMC.
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As a general guideline, the initial step in qualifying a chemical air filter should begin with vendor performance data generated from a full-scale laboratory system, showing low parts-per-billion (one molecule in 1 billion air molecules, 10-9) challenge concentrations of the critical compound(s) of interest, or a representative compound when the actual target compound is toxic or unstable. Testing smaller samples of filter media may be quicker and less expensive but extrapolating the results to full-scale performance is often non-representative for the actual filter. Requiring all vendors to submit full-scale test data expressed in standard units will provide the end user with a method for accurate and concise comparison of products.

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The next step in filter selection should include a list of reference installations from a similar facility with similar processes. Additionally, those references should be accompanied by data collected over time from an actual installation that characterizes the product’s initial removal efficiency at commissioning as well as its long-term performance to demonstrate the useful service life (Fig. 3).

A major trend in filtration for many newer IC fabs is the desire to capture several categories of AMCs in a single, easy-to-use filter. This trend is based in part on the need to lower the cost of initial purchase, simplify installation and maintenance, minimize inventory, and save on electrical operating costs due to the lower pressure drop of a single filter. There are single-filter options available that target and remove acids, bases, and organic compounds, but not all are of equal value. It is important that a product has a balance in performance for all AMC categories so that the maximum lifetime for each is achieved when the filter is exhausted. A filter lasting four months for organics and 12 months for acids and bases will not provide a good return on investment. In this case, the “ink-jet cartridge” effect occurs: eight months of acid and base filtration capacity would be lost due to the need to replace filters for organic protection.

Facility managers should also determine if the chosen filter technology has the flexibility to provide different chemistry formulations that can evolve with the chemistry changes in the cleanroom. The AMC composition in a fab can change over time, as will the sensitivity of the manufacturing processes and tool OEM specifications for ambient cleanliness. Ideally, the filter media formulation is configurable to meet the customer’s future AMC needs with a cost-effective product that fits into the same installation footprint.

Finally, it is vital to gauge filter performance and cleanroom chemistry changes and to optimize filter lifetime. Facility managers and tool owners need reliable, pre- and post-installation AMC data, without which the integrity of the performance results is in question.

One in a trillion

Measurement of AMC in semiconductor cleanrooms has been commonplace for more than 10 years. Determination of ammonia levels that affect wafer surfaces (T-topping) started with 248-nm technology and its increasingly sensitive resists. With the advent of 193-nm UV exposure of wafers, other AMC issues and a larger number of compounds of concern have cropped up. Speciated measurements of acids, bases, and organics became necessary and, in fact, were soon mandated by tool OEMs. AMC classes and measurement requirements were defined by SEMI and implemented into technology roadmaps by the International Technology Roadmap for Semiconductors. They typically consist of acids (A), bases (B), condensable organic compounds (C or O), dopants (D), and metals (M). C-class compounds also contain so-called refractory components (molecules containing Si, P, S, etc.), which can cause severe and irreversible degradation of optical components by changing the refractive index of the optics.

Whereas health issues are typically defined in the parts-per-million concentration range (one molecule in 1 million air molecules, 10-6), AMC was found to affect processes and tools in the parts-per-billion range, 1,000 times less concentrated than typical OSHA requirements. With humans emitting parts-per-million-level ammonia, benign hand lotions being made of silicon-containing compounds, and a suite of process chemicals in use, cleanroom AMC concentrations increase over time if they are not exchanged or filtered.

Modern AMC requirements for cleanroom ambient air has been as low as 0.1 ppb or 100 parts per trillion (molecules in 1 trillion gas molecules, 10-12)–the equivalent of less than one person out of Earth’s entire population! Some purge gas specifications are now as low as 10 ppt for any one AMC class, making it a true challenge for analytical solutions to measure this concentration level. Suddenly, analytical laboratory environments are too dirty, chemically speaking, and most materials touching the sample gas can cause artifacts that are as large as or larger than the AMC to be measured. Human breath, human perspiration, particles from fabrics, the pipette touching the (supposedly clean) counter surface, the quality of chemical supplies, and the leaching of vial materials become obstacles in achieving detection limits that are necessary for confident results.

OEMs require low-level measurements of AMC throughout the wafer process due to the ever-increasing sensitivity of resists and chip features, as well as staggering losses for every hour of process downtime. To meet these requirements, filter performance needs to be verified, AMC levels of compressed gases need to be checked, and cleanroom ambient AMC levels need to conform to minimum standards–standards that are tightened year after year as the number of compounds to be measured expands. Considering these risks, the tool engineers’ desire to measure AMC levels and see the results in real time is understandable.

Whereas online measurement is possible for a few compounds, such as ammonia and perhaps a few volatile and non-reactive organic components, nature has placed constraints on our ability to measure everything in real time, or at a low cost with minimal complexity. Sticky molecules, the surface area of sample tubing, reactions in the sample path, interferences, and low concentrations prevent us from measuring many, if not most, compounds in real time using simple means. Strong acids (SO2, HCl) don’t work that way, nor do organic molecules of the highest interest (i.e., molecular weight). Thus far, we have not come up with a technology that measures it all in real time and with minimal effort. Plus, the most reliable instruments for parts-per-trillion-level analysis still require the most capable operators, yet running multiple gas chromatography-mass spectrometry (GC-MS) systems with 24/7 advanced degree operation is cost prohibitive.

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The current solution to these challenges is to measure the important compounds infrequently through grab sampling to generate a data set (Fig. 4). Adsorbent traps such as Tenax TA, Carbotrap, and Anasorb are commonly used to capture organic AMC, while deionized water impingers/bubblers are used to capture all soluble compounds like acids and bases in cleanroom air or supply gases. These devices draw a large amount of air through them to concentrate the AMC on the traps–the air passes through, very much like an AMC filter–then analyze what has been captured with modern analytical machinery. Detection limits are inversely proportional to the amount of air collected; concentrations of 10 ppt can be achieved by collecting 30

In the aseptic environment, an automated EM program ensures optimum control over potential contamination

By Bob Toal, MODA Technology Partners

With increased demand for production of modern therapies using vaccines, injected drugs, and human tissue, there is an increase in the number of manufacturing facilities requiring aseptic processing conditions. In aseptic processing, where the end product cannot be terminally sterilized, it is especially critical that product is manufactured in an environment free of contaminants. And once the aseptic environment is established, it must be closely watched via comprehensive environment monitoring (EM) programs to ensure processing areas are under control for potential viable and non-viable contamination.

Current state of EM: Bigger, but not better

Although the requirements for EM have been growing in terms of number of samples and sampling sites, the paper-based, labor-intensive programs that are so prevalent in the industry are not capable of delivering the maximum value desired.

According to J. Agalloco et al., “Comprehensive EM programs have been a general practice in the industry since the late 1980s. Since then, these programs have become more expansive. Unfortunately, there is no evidence that the EM programs of today are functionally superior to those of 15 years ago. They are certainly more costly and far more time-consuming, but it is not generally believed that they do a better job of assessing product safety.”1

The paper-based QC process

From the smallest biotech operation to the largest pharmaceutical manufacturer, the traditional EM process is manual, paper based, time consuming, and error prone. First, the process relies on paper schedules to drive the work. Next, in cleanroom areas, technicians refer to the paper schedules and in many cases, use permanent markers to mark information about samples taken onto the sample media (petri dishes, vials, etc.). In the laboratory, manual reconciliation steps precede numerous manual entries in paper logbooks to track lab testing and processing activities. Finally, when test results are ready for recording, they are manually entered into spreadsheets, small database applications, or perhaps a laboratory information management system (LIMS). Notifications on any deviation found are sent via manual e-mail.

The massive amount of EM test data generated is fair game for agency audits. Today this typically involves sifting through volumes of binders with paper-based results and reports. For corrective and preventive action (CAPA) purposes, building a set of trend reports may require more than eight weeks. Unfortunately, by the time a trend of activity is developed and recognized, the condition causing the trend is likely to have changed, making it difficult to support corrective action activities and nearly impossible to perform meaningful preventive actions.

Concepts for automation

Organizations like the Parenteral Drug Association (PDA) are actively promoting automation in the cleanroom and in the laboratory to remove the manual processes and paper. In the cleanroom, the clear recommendation is for automated collection of data as quickly as possible at the point of sample. From the EM Handbook published by PDA:

  • “…consider cleanroom touch pads or computer terminals that allow for automated data entry in the room.”2
  • “For those procedures which involve manual data collection, palm pilot-type of data collection devices may be necessary that can directly download to the computer system, and allow for direct data transfer without the risk of contamination.”2

And in the laboratory, the call is for automation in reporting as well. From the same EM Handbook publication:

  • “…analysis and trending of environmental data is essential to aid in the interpretation of process stability and assess overall control performance.”
  • EM reports must be “…accurate, traceable, timely, and well-documented.”3

EM automation challenges

Leveraging automation to increase the efficiency of collecting and tracking environmental samples in an aseptic environment poses significant challenges. In traditional manufacturing and packaging environments, computers are commonplace and dramatically increase the overall efficiency and quality of operations. However, computers, like all other equipment in a cleanroom environment, must be sanitized in order to destroy potential contaminants that might be growing on their surfaces. Heat, radiation, and chemical disinfectants cannot be used on standard business computers without damaging them. Industrial or “rugged” computers that can be sanitized exist but are typically deployed as a fixed workstation used to control or monitor a specific operation.


Figure 1. Sampling cart with mobile data acquisition devices mounted.
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The EM sampling technicians must travel throughout the aseptic facility, on a pre-defined route, collecting and labeling samples. A fixed workstation would not improve operational efficiency and in fact would result in increased foot traffic and potential congestion within the facility. Installing multiple EM kiosks throughout the facility is not economically feasible, as industrial computers that can withstand chemical disinfection are significantly more expensive than traditional business computers.

Mobile technology overcomes challenges

The ideal device is small, lightweight, transportable, and capable of being sanitized with commonly used cleaning agents. It is able to leverage wireless or radio frequency (RF) technology to provide connectivity to and communication with other computer systems that support the manufacturing process. It also provides the ability to read and print barcodes and RFID tags to eliminate the need for paper schedules and hand-written sample labels and sampling records.

The individual components of an ideal solution include a rugged wireless tablet PC with touch screen, a wireless barcode scanner, and a rugged, thermal barcode printer with sterile label stock. And these components can be pulled together and mounted on hardware that is already commonly used for sample collection: a stainless-steel cart. The shelves of the cart can continue to be used to carry sampling media and portable testing equipment such as air particle counters.

Best practices requirements

With an automated, paperless solution, a QC department can enter and maintain all EM program standard operating procedures (SOPs) electronically. Sampling and lab processing tasks are assigned based on the rules as defined in the SOPs. By using a sampling cart with mobile data acquisition devices as described, technicians can simply move to a sampling site and run a scan on a fixed barcode that identifies the site. The scanned barcode can then trigger all sampling tasks required for that site.

Rather than using a permanent marker on media plates to record information, the system can generate a barcode label that is placed on the sample media. The barcode labels are produced from a thermal printer on sterile stock, all suitable for a cleanroom environment. Information about each sample is uploaded to a data repository immediately at the point of sample.

In the laboratory, there will no longer be a need for manual reconciliation of actual vs. planned samples taken. All of the remaining lab processes, including automatic notification on deviations, will be driven by electronic workflows and tracked through completion. Analytical tools should include a comprehensive set of reports that not only meet audit requirements but enable execution of meaningful investigations for both corrective and preventive action resolution.

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Based on industry best practice, here are the top 10 requirements for an automated EM program.

1. Workflow driven. The solution must provide the user with a means to define and maintain their EM program SOPs in electronic form. The SOPs identify the test protocols, sampling sites, and frequency of monitoring needed to comply with cleanroom standards, operational procedures, and validation criteria. These workflow definitions are then used to drive the required EM tasks and to help ensure compliance.

2. No paper records and manual error-prone processes. Scheduling of work is driven automatically as defined by the electronic SOPs. Work assignments are made electronically without paper schedules. Working in a cleanroom, technicians move from site to site to collect samples and perform tests. A sanitized, mobile, touch-screen computer supports a paperless operation to automatically collect and upload information about each sample. The system will read barcodes on sites and equipment (e.g., air particulate counter or viable air sampling device) to quickly identify scheduled tasks and assure valid use and calibration of equipment. For personnel samples, labels for the correct number of samples needed are generated based upon the people in the room at the time of sampling and the sites (e.g., glove and gown location) to be sampled. The system also must enable the technician to record the identity of the individual from whom the sample was taken.

3. 21 CFR Part 11 compliant. In a paperless solution, all of the electronic records created must contain proper audit information and all electronic signatures must be performed in compliance with regulating agency requirements.

4. Support full spectrum of test methods. The solution must be able to support all viable and non-viable testing activities including tests of air, surfaces, utilities (water, gas), and personnel.

5. Disconnected operation. The solution must be able to support operations in a disconnected mode in the event of a wireless network connection drop. While performing sampling operations in a cleanroom area filled with many stainless-steel items, it is a common occurrence for the wireless network to be temporarily unavailable.

6. Device integration in cleanroom. Where possible, the solution should support device control from the mobile platform and a direct download of data. A common example of this integration is with non-viable air particulate counters. Another is with in-line water testing for total organic carbon and conductivity.

7. Device integration in lab. Many utility and water tests are typically performed in the laboratory. Devices that produce electronic output should be integrated to provide either a direct download or a file-based transfer of results. This includes devices that test for endotoxin, conductivity, and total organic carbon.

8. Comprehensive reporting. Reports are required to monitor daily operations and assist in audits, product release decisions, and performing investigations. Reports must include:

  • Results by a specific batch/lot, to support batch closeout.
  • Results and trends for a specific room and time period.
  • Results and trends for specific personnel over specified time periods.
  • Results and trends for a specific organism found over specified time periods.
  • Results and trends for a specific media lot, to review sterility assurance

9. Automatic notifications for out-of-spec events. The solution generates alerts and actions with immediate notification via e-mail for out-of-range results and for trends, such as three consecutive non-zero counts.

10. Ability to handle exception cases. The solution needs to be able to gracefully handle common cases where the process did not go exactly as planned (e.g., dropped media plates, nobody in room for personnel testing, etc.).

Process for viable sample collection

The typical paper-based process for a sample collection regimen is as shown about 8 hours per person, per shift.

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By employing a best practices-based, mobile data acquisition platform for sample collection, the process time is cut in half–to 4 hours per person, per shift. This savings has significant implications when it is applied to multi-technician, multi-shift operation for a one-year period.

Process for non-viable air testing

A typical paper-based process for collection of results from non-viable air particulate devices is shown in Fig. 4. In this process, a paper printout of results generated by the device is pasted into a logbook. The results are then hand-typed into a spreadsheet and reconciled vs. the printout. Once data are entered into a spreadsheet, trend lines over periods of time can be manually produced via a reporting tool.

The paperless process for collection of results from non-viable air particulate devices starts with the mobile collection tablet that will drive the devices with a user interface that includes commands for initialize, start, stop, and collect results. The connection to the device could be wired via USB, etc., or it could be wireless. Results collected are automatically uploaded to the data repository where reports and trends can be viewed in real time. Any results exceeding alert or action levels will generate automatic notification via e-mail.

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By removing the error-prone, manual data entry steps, the effort and time savings over the paper process is significant, with an average savings of 6 hours per person per shift. As with the viables sampling, when this savings is applied to multi-technician, multi-shift operation over a one-year period, it is very compelling.

Case study results

The opportunity for time and cost savings is most evident in high-volume operations where hundreds of thousands of samples are taken on a yearly basis. The transformation of a paper-based EM operation for handling 360,000 samples per year to a paperless solution turned a positive return on investment within six months. Key drivers for savings were elimination of batch data entry, reduction of missed samples, and elimination of template-to-media reconciliation. Another area for savings was in the production of reports where the paper-based monthly trending reports required 30 person-days. This task was effectively eliminated.

It is important to note that there are organizations with rather low-volume sampling programs that have automated their EM processes primarily for enhanced compliance and decision support. In one case, where an organization produces patient-specific therapeutics, the cost of losing even one product batch to an untraceable EM excursion is just too high.

Conclusion

Best practices-based automation concepts for EM are actively promoted by leading, well respected industry organizations like PDA. These automation concepts are also consistent with the FDA initiative for process analytical technologies (PAT) , which aims to automate more of the drug manufacturing process, remove variability, anticipate problems, and make corrections earlier in the process before an entire product batch has to be rejected.

Implementation of an automated, paperless, best practices-based solution for the entire QC microbiology process associated with EM, utility, and product testing, provides an opportunity for significant, tangible return on investment due to the reduction in time needed to execute the required protocols. An additional benefit is the immediate availability of higher-quality information that can quickly and accurately provide EM evidence to support batch release and ensure regulatory compliance.

Bob Toal is a director at MODA Technology Partners in Wayne, PA (www.modatp.com) with more than 25 years’ experience in IT systems integration.

References

  1. J. Agalloco, J. Akers, and R. Madsen, “Aseptic Processing: A Review of Current Industry Practice,” Pharmaceutical Technology, 2004.
  2. J. Moldenhauer, Environmental Monitoring–A Comprehensive Handbook, Vol. 1, p. 24, PDA.
  3. J. Moldenhauer, Environmental Monitoring–A Comprehensive Handbook, Vol. 2, pp. 33, 50, PDA.

ESD prevention and protection


September 1, 2008

Compiled by Carrie Meadows

No matter where you sit, stand, or walk, or what you wear in a critical, clean environment, eliminating electrostatic discharge is a top consideration. To eliminate shocking results, here’s a sampling of ESD prevention and protection products.

Static control blow-off gun

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The durable 190 HP (90803-11080) ionization gun is designed for applications with a large coverage area or drying and cooling requirements such as for circuit board applications. The 10 to 1 boost from the venturi also makes the 190 HP a very energy and compressed air efficient static control blow-off gun. The 190 Series guns can be factory rebuilt and guns and power supplies can be replaced separately, resulting in a very low lifetime cost of ownership. The Standard Model T series AC power supply (sold separately) is available in 120-V or 220-V primary and 4-kV output and can support two guns. The Model B series Equal-Ion power unit (sold separately) is designed to be used with the 190 Series static control guns in applications where

New Products


September 1, 2008

Compiled by Carrie Meadows

Ozone generation and purification system

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In pharmaceutical and cosmetics production, purified water forms the basis of all processes. Ozone ensures an effective disinfection of deionized purified water. With the Steritron, ozone is produced by electrolysis from the purified water available. The oxidation potential of the gas destroys the cell wall and membrane of microorganisms without chemically or physically modifying the water. The system’s process generates ozone in highest concentrations–up to 18 weight percent of ozone in oxygen. The electrolytic ozone generator is easy to install, low maintenance, and eliminates operating stops for rinsing cycles. It also removes the need for steam sterilization of the plant distributing purified water. The appliance meets the EC directives for electromagnetic compatibility and is CE compliant.

Christ Water Technology Group
Mondsee, Austria
www.christwater.com

Increased liquid and vapor protection with garment

DuPont’s Tychem® BR garment, certified to NFPA 1994 Class 2, is lighter in weight and less cumbersome than a traditional fully encapsulated suit. It provides increased vapor and liquid protection, is easier and faster to change into, and is more cost-effective than traditional garments. Tychem® BR fabric has been successfully tested against more than 240 chemicals. It provides durability and tear, puncture, and abrasion resistance. The NFPA 1994 Class 2 Standard defines an intermediate level of chemical, liquid, and vapor protection. Class 2 garments are certified for situations where there is an immediate danger to life and health and must be worn with a self-contained breathing apparatus (SCBA). The garment is designed to be used with NIOSH-approved chemical, biological, radiological, and nuclear (CBRN) SCBA respirators.

DuPont™
Wilmington, DE
www.dupont.com

Reusable duct covers

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Keeping duct work clean from the start is the first step in IAQ and being able to reuse a temporary end cap is an economic advantage. Ductcaps’ easy on, off, and back on again design allows the contractor to nest spirals and keep all of them clean with the use of only two Ductcaps. It is also easy to carry the duct by putting some slack in the cover. Ductcaps are now offered in 70-, 80-, and 100-in. versions.

MEZ-TECHNIK GmbH air system products
Reutlingen, Germany
www.ductcap.net

Mat adhesive strips

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Grip Strips are slip-resistant strips that adhere to sponge-backed mats placed on smooth, polished, or painted floors. The antimicrobial polymer is permanently tacky; only a few are needed, even in high traffic areas. The adhesives help keep anti-fatigue mats in place for safety and comfort of personnel. The glue is “active” and becomes more sticky over time. Strips can be cleaned with Simple Green® or a similar cleaner.

Wearwell
Smyrna, TN
www.wearwell.com

Low-linting wipes

LITE WIPES are made with absorbent, low-linting cellulose. Two sizes are available: LW6414 (comparable to Kimwipes® 34155) are 4.5×8.3 in. and are available in 300/box quantities; LW6425 (comparable to Kimwipes® 34256 and 05514) are 15.0×16.6 in. and are available in 140/box quantities. Push-up dispensers are available for the wipes.

High-Tech Conversions
East Windsor, CT
www.high-techconversions.com

Durable flooring with fast-curing sealant

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Stontec TRF is a flooring solution for the pharmaceutical and biotech industries. The versatile flooring can be laid over concrete, wood, brick, quarry tile, or metal. Its durable, stain-resistant surface is suited for pharmaceutical production and laboratories, washdown areas, corridors, and other high-traffic areas. Vinyl flakes meld into the high-performance epoxy bonding coat. A fast-curing, UV-resistant urethane sealer resists sun damage and discoloration. The quick cure time–as little as 4 hours for foot traffic–keeps shutdown time to a minimum.

Stonhard
Maple Shade, NJ
www.stonhard.com

Particle-free cleanroom labels

UltraTape Industries, a division of Delphon Industries, has added cleanroom labels to its product line. The same strict cleanroom standards used to manufacture the company’s existing tape products are used for its new line of labels. Available in a variety of substrates and adhesive options, labels are particle- and residue-free and are appropriate for use within the most critical environments. UltraTape manufactures adhesive tapes and labels for the semiconductor, pharmaceutical, aerospace, medical, and electronics industries.

UltraTape Industries
Salem, OR
www.cleanroomtape.com

Airborne particle counters

The ELITE™ Sensor Technology has been incorporated into several Lighthouse products, including the REMOTE 2000 Series airborne particle counters. The REMOTE 2000 Series design combines a dual-mirror patented optical system and the ELITE™ Sensor Technology resulting in a small, accurate, and reliable 0.2-μm sensor. The airborne particle counters integrate seamlessly into large facility monitoring and management systems. Using Pulse, 4

Back to school days


September 1, 2008

It seems hard to believe, but summer is already winding down. Days are getting shorter, and the kids are heading back to school. It’s also the time when we in the contamination control industry start gearing up again, after a short hiatus, for our own form of continuing education–the fall conference and exhibition schedule.

Fall and Spring are the seasons of conferences for just about every industry, and since contamination control technology crosses over into so many high-technology professions, it’s always particularly busy for all of us.

The value of attending educational conferences and presentations is unquestionable, however. It’s where the very latest information across a wide spectrum of interest areas and perspectives can be found and where there is an opportunity to connect directly with the experts. It’s also where we have an opportunity to see and learn firsthand about new products and systems, with top-level experts on hand to answer questions and listen to our concerns.

Still, it’s not easy these days to physically get to all of the conferences and shows we’d like to. Travel costs are enough of an obstacle, let alone the time factor, and with greater and greater demands being placed on everyone’s time, this is perhaps the most daunting challenge.

It is precisely for these reasons that CleanRooms is offering our first ever virtual conference and exhibition. To be held on October 21 from 8:00 a.m. to 6:00 p.m. US Central Time, the “CleanRooms Worldwide eVent” will allow you to see and hear top-level presentations, ask questions of the speakers, visit the booths and engage in discussions with product and technology suppliers and their representatives in a trade-show environment, and converse or network in a social atmosphere with professional colleagues old and new–and all without ever leaving your own work space.

Today’s online technology has really advanced dramatically to be able to efficiently and seamlessly deliver this fully interactive environment anywhere in the world that has access to the Internet. But you really need to experience it for yourself to appreciate it fully. And why not?–it’s completely free to register and attend.

Check out the CleanRooms Worldwide eVent advance conference program and exhibitor list now posted at www.cleanrooms-worldwide.com. You can also get just a taste of the environment by viewing the virtual event demonstration video. We’ve scheduled the show hours to make it possible to spend at least a couple of hours regardless of your global location. So plan to take just a bit of your valuable time to visit the show on October 21. And yes, you can pre-register online as well. I, and other CleanRooms staff members, will be there at the CleanRooms booth. Please stop in.

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John Haystead,
Publisher & Editor

By George Miller

If nothing else, the recent Salmonella Saintpaul outbreak from contaminated jalapeño and serrano peppers demonstrates that food trace-back in the global supply chain requires a combination of resources, coordination, and speed. It also requires a strategic balance of proactive and reactive tactics.

But another requirement is persistence of effort, during both outbreak and non-outbreak times, especially in encouraging the public to seek medical help when people get sick.

“Education of the public is perhaps the most important tool in fighting food-borne illness at the global level,” says Rob Donofrio, M.S., Ph.D. candidate, director for microbiology at NSF International (Ann Arbor, MI), an independent, not-for-profit organization that writes standards for food, water, and consumer goods protection.

He adds that sick people are the most timely data points in a trace-back investigation. By August 14, the victim count had reached 1,423. Yet even when victims go to a hospital, days will already have passed since they ingested the affected food, and memories of food eaten and ingredients used will be fading.

During a trace-back investigation, technology tools come into play when stool samples from sufferers become available for use by investigators in identifying the contamination culprit.

“The detection techniques are there,” says Donofrio. “But the time required to get a DNA fingerprint still includes the time it takes to grow the organism.”

Spreading the word

Once investigators find what they believe may be the beginnings of an outbreak, they need to inform other members of the health-care community to spread the word and identify similar cases. In the U.S. investigators activate PulseNet–a national network of public health and food regulatory agency labs coordinated by the Centers for Disease Control and Prevention (CDC). PulseNet encompasses state and local health departments as well as federal agencies. So its labs, expertise, and database capabilities are available to trace-back investigators at all levels: national, state, and local.

PulseNet investigators perform standardized molecular subtyping (DNA fingerprinting) of food-borne disease-causing bacteria using pulsed-field gel electrophoresis (PFGE). PFGE helps investigators distinguish strains of organisms such as Escherichia coli O157:H7, Salmonella, Shigella, Listeria, and Campylobacter.


Figure 1. Starting in April and through August 14, CDC has identified 1,423 persons infected with Salmonella Saintpaul (increased from the 1,401 shown here), with the same genetic fingerprint identified in 43 states, the District of Columbia, and Canada.
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The effort can get expensive, says Donofrio. So the states that are able to make such investments–$70,000 to $100,000 for a riboprinter; $30,000 to $50,000 for electrophoresis gear, plus people to run the equipment and analyze results–will have a decided advantage over those unable to do so, who must ship samples to federal facilities and await results before resuming an investigation.

Lucky Minnesota

Minnesota is one of the lucky states having such equipment, according to Kirk Smith, food-borne disease supervisor at the Minnesota Department of Health. The department has staff members “who have the expertise to interpret lab results, and who just happen to be good at detective work,” he says.

Smith and his team tracked the state’s Salmonella Saintpaul outbreak from its first appearance in Minnesota, sharing information with CDC and FDA, and eventually confirming that they were working on the same outbreak.

The Minnesota team traced the outbreak to a Texas distribution facility and eventually to the Mexican farm, with federal investigators apprised and involved via FoodNet, CDC’s Foodborne Diseases Active Surveillance Network.

“We have more people focused on food-borne illnesses than other states,” says Smith, in part because of its relationship with CDC. “As a member of FoodNet, we get money from CDC to use on our own resources, as well as using its resources.”

Minnesota employs a centralized trace-back system that starts when the clinical lab sends Smith’s office DNA-fingerprinting results, usually complete within two or three days of receiving stool samples. “Then we start interviews, and we continue conducting them on a real-time basis, as soon as we can reach victims.”

Smith places great importance on the interviews. “If you don’t collect the information right away, it’s that much harder to get because people forget,” he explains.

In the Minnesota Salmonella Saintpaul trace-back operation, Smith’s lab received 10 isolates between June 23 and 27. “That’s a lot,” he notes. “We usually don’t get 10 in a year.”

Restaurant identified

Smith’s team began interviewing victims. A victim from the second interview, conducted on July 29, identified the restaurant later found to be the cause of Minnesota’s outbreak. “It’s a Mexican restaurant in the Twin Cities, a table-service restaurant,” Smith says. (The name of the restaurant was not released at press time.) He started a full-blown investigation on July 30.

“We asked people what they ate, which menu items, which ingredients they remember, and whether any ingredients were added or removed,” he says. “Then we find and interview people who ate at the same restaurant around the same time, both those who got sick and those who didn’t.”


Figure 2. An automated immunoassay instrument is one tool FDA chemists use to detect cell surface antigens of Salmonella on food products. Photo courtesy of FDA.
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Investigators then visited the restaurant, checking the meals and appetizers served on the day in question. They determined the ingredients used in what the victims ate, and then got the restaurant’s vendor invoices for its purchase of those ingredients. It turns out that the restaurant used the contaminated jalapeño peppers primarily as a garnish.

A hot trail

Following the source of an invoice, Minnesota investigators visited a Texas distribution facility–Agricola Zaragoza Inc. of McAllen, TX, a big produce warehouse used by several distributors–where they found the “smoking pepper.” Agricola issued a recall on July 21 for peppers distributed since the end of June.

From Texas, the pepper was traced to a packing facility in Nuevo Leon, Mexico, and then to a farm in Tamaulipas, Mexico. A second contaminated product was found at the packing facility and traced to another farm in Tamaulipas.

Further investigation at the first farm led researchers to believe that contaminated irrigation water, produced via runoff after the farmer used animal manure as fertilizer, or contaminated water used to rinse or clean peppers, was most likely the source.

“There are more outbreaks that we don’t solve than we do,” says Smith. “Most clusters involve three to ten reported illnesses. But when they get this big, we tend to solve them.”