Food bacteria is here to stay, but that doesn't mean it can't be minimized
Mark A. DeSorbo
CHICAGO, IL-Zero risk is not a reality.
That's the gist of “Emerging Micro biological Food Safety Issues: Implications for Control in the 21st Century,” a report compiled by 21 scientists at the Institute of Food Technologists (IFT).
The authors of the report say the bacteria that cause food poisonings are not going away, despite gallant efforts to eliminate them. Consumers, they say, should be aware that new germs arrive in imported foods and bacteria already here morph into new and more virulent forms.
“Foodborne illness in the United States is a major and complex problem that is likely to become a greater problem as we become a more global society,” according to the report.
That means there will always be a risk, says Frank Busta, a professor emeritus at the University of Minnesota and one of the authors who penned the IFT report. “And that's very true of every risk in our lives,” says Busta, a past president of the food technologists' organization. “It could be a high risk or it could be a low risk. There is some risk, but no risk is not a reality. Our aim in food-safety programs is to reduce that risk.”
Reducing risk, he says, means setting a public health goal of allowing contamination to be measurable.
“Let's say, hypothetically, that there are 1,000 Listeria (microbes) per gram of food, but we decide we should have no more than a 100 Listeria per gram of food at consumption,” Busta says. “That, to the best of our knowledge, is a non-infectious dose for someone whose immune system is not compromised. Therefore, we are setting a measurable goal of reducing the risk tenfold, but not eliminating it.”
The Listeria monocytogenes bacteria is a pertinent example because the report indicates that it so common in the environment, it is “practically impossible” to keep food entirely free of it.
Listeria contamination, Busta says, is frequently an environmental problem. “It grows on the ceilings, the walls, the floors, and that's why contamination control is extremely important,” he says. “Many foodborne illnesses are the direct result of incomplete or inadequate cleaning.”
Cleaning programs in a food-processing environment may be comprehensive, but they don't mean anything if they aren't executed correctly. “Sometimes organizations don't give enough emphasis to that aspect or pay their personnel enough to do it,” Busta adds. “They need to elevate the cleaning crew to the elite, and pay them the same as their production people. It's that kind of emphasis that gives you a good program.”
Fellow report author Douglas Archer, a professor of food science and nutrition at the University of Florida, Gainesville, agrees.
“There is no such thing as too clean,” he says. “The role of cleaning personnel is critical to the health and the success of the company. Cleanliness is so important in preventing cross-contamination.”
Bantering bacteria colonization
Archer, who served as deputy director for the U.S. Food and Drug Administration's (FDA) Center for Food Science and Applied Nutrition (CFSAN) for 20 years, noted that the IFT report also discusses the importance of learning more about biofilms, stable, hard-to-kill colonies of microorganism that can live and thrive on any surface.
“It's amazing how little we know about biofilms,” he says. “Many of these biofilms can live on stainless steel surfaces and cannot be killed by antibacterial agents. They are impregnable to chlorine and disinfectants.”
Bacteria can not only become resistant to some cleaning agents, but to antibiotics as well, and IFT scientists warn against overusing drugs in livestock, saying that it is causing microorganisms to become impervious and resilient.
“The widespread use of antibiotics in animal production and in the treatment of human illness facilitate the emergence of antibiotic resistance,” the report says. “The selective pressure caused by antibiotic administration causes the microbial populations that harbor the appropriate resistance determinant(s) to flourish. These antibiotic-resistant microbes can make their way into humans through contaminated food or animal-to-human transmission.”
Whether it's within an animal or a clean environment, Archer says “organisms are under stress and can change, and there's no telling if the outcome will be a good thing or a bad thing.”
Scientists also say the increasing use of manure as a fertilizer poses the risk of spreading harmful bacteria to food, either by contaminating irrigation water or by coming into contact with crops.
Manure, which harbors bacteria such as E. coli O157:H7, campylobacter and salmonella, substitutes for chemical fertilizer on organic and conventional crops. In some foreign countries, chicken manure is fed to farm-raised shrimp.
The report also raises concerns about federal regulations on imported fruits and vegetables and the potential for new pathogens getting into the country. According to the report, Cyclospora cayetanensis came to the United States through imported produce and rare forms of salmonella also have been appearing in the country.
“Certainly, you can grow produce that is free of pathogens in developing countries. It's just a matter of sanitary practices and the quality of water that is used for irrigation,” Michael Doyle, a University of Georgia microbiologist who assisted in the study told The Associated Press.
The FDA inspects less than two percent of imported fruits and vegetables, while major supermarket chains, worried about new outbreaks of salmonella and other bacteria, have started requiring domestic and foreign produce suppliers to be inspected by private firms.
From field to, er, digestion
According to the report, better monitoring of foodborne illnesses is needed to spot trends and identify causes. For example, doctors too often treat patients for food poisonings without reporting the illnesses to public health authorities or ordering tests to determine the exact causes. This lack of reporting could mean that government agencies and food companies may not be aware of new pathogens or dangerous products.
To fully combat that problem, Busta recommends another approach other than the industry slogan of providing safe food “from farm to fork.” Although he admits the humor in his recommendation, Busta says that viewpoint must be broadened to provide safe food from “field to flatulence.”
“If we have new nasty organisms coming up, we have to consider how we clean, how we eat, how we change what we eat and is the population susceptible,” he says. “We may be ill for some other reason that makes us susceptible. A person receiving chemotherapy treatments has to be careful about how their food is prepared. Various things can knock out our immune system, and as a result of that, we are far more susceptible. You have to involve the whole process, including the human being and the organisms within their digestive tract.”
|Early times||Heating||Cooking foods kills many foodborne pathogens.|
|1770s-1800s||Canning/thermal processing||Significant discoveries in response to industrialization forces and Napoleon’s armies’ need for less dependence on local provisions.|
|1890s||Pasteurization||Thermal treatment of raw milk to prevent milk from transmitting pathogens.|
|1920s- 1930s||Safe canning/processing parameters||Calculation of product heat penetration curve and initial microbial contamination level to determine minimum time-temperature combination for commercial sterility.|
|1940s||Freezing||Mechanical quick-freezing methods to preserve while maintaining quality.|
|1950s||Controlled atmosphere packaging||Reduced oxygen levels, increased concentrations of carbon dioxide or selective mixtures of atmospheric gases to limit respiration and ethylene production, delay ripening and decay and increase refrigerated product shelf life.|
|1960s||Freeze drying||Rapid deep freezing followed by sublimation of water by heating the frozen product in a vacuum chamber. Best know applied to coffee to preserve delicate aroma compounds and maintain flavor and color.|
|1940s-1990s||Aseptic processing and packaging||High-temperature, short-time sterilization of food product independ-ent of the container, container sterilization and filling of product in sterile atmosphere, resulting in increased food quality and nutrient retention.|
|Irradiation||Non-thermal process to kill pathogens, insects and larvae, inhibit sprouting and delay ripening with and food spoilage.|
|1990s||Carcass spray treatments (e.g. water, acid), steam vacuuming, steam pasteurization||Carcass decontamination interventions to meet biological perform-ance criteria.|
|High-pressure processing||Food subjected to specified pressures and temperatures to preserve food while maintaining quality.|
Changes in how foods are processed-such as leaving out salt-can inadvertently lead to new safety problems by making food more hospitable to bacteria, or by causing the bacteria to evolve into hardier forms.
The report cites how yogurt manufacturers started replacing sugar with an artificial sweetener, which led to the growth of the bacteria that causes botulism. The sugar was removing water from the yogurt, making it difficult for the bacteria to grow. Yogurt was then reformulated to eliminate the problem.
“There are a lot of complicated factors resulting in foodborne illness,” says Jenny Scott, senior director of food safety programs for the National Food Processors Association (NFPA; Washington, DC). “You can focus in on one aspect, but things change. You think you are licking them, but something else pops up.”
To Busta and Archer, however, new things that pop up are the direct result of a human being.
“We, the human being, are two of the three factors in foodborne illnesses,” Busta says.
Archer says outbreaks and illness are preventable and are most likely caused by “a lapse in human performance.”
“It comes down to someone simply made a mistake and did not observe basic food-safety principles,” he adds. “Just getting people to was their hands would reduce foodborne illness by a huge percentage.”
The IFT's report, “Emerging Micro biological Food Safety Issues: Implications for Control in the 21st Century,” is available on the organization's Web site at www.ift.org.