Globalization impacts food safety standards in the United States

Multifaceted strategies may be necessary to combat the increased risks.

Issue: July 2008

BOSTON — Increased reliance on food sources outside of the United States could lead to an increased incidence of foodborne illnesses, according to research presented in a symposium on globalization and food safety at the 108th General Meeting of the American Society for Microbiology, held here recently.

Less than 1% of food that comes into the United States is visually inspected and less than 0.5% is actually handled and tested, according to Michael Doyle, PhD, Regents Professor of Food Microbiology and Director, Center for Food Safety at the University of Georgia in Griffin.

Such a small percentage is perhaps due to the fact that there are only 80 FDA employees inspecting all imported food products coming into the country, according to Lee-Ann Jaykus, PhD, of the department of bioprocessing, and nutrition sciences at North Carolina State University in Raleigh. Factor in that much of the food is coming from developing countries with poorer standards for safety and inspection than the United States and the result is what many researchers fear: that foodborne infections may increase in the coming years as a consequence of increased globalization of our food supply.

Efforts to combat this problem need to start at the source and be maintained through the farm-to-table continuum. Presenters at the symposium discussed the necessity of surveillance methods to detect outbreaks, epidemiological investigations, traceback to the source of contamination, institution of control measures and multidisciplinary, multinational investigative teams that can attempt to identify and address potential food safety problems before they become public health issues.

Robert Tauxe, MD, MPH, deputy director, CDC Division of Foodborne, Bacterial and Mycotic Diseases, said that “contamination can occur at any point during the production process of food.” He cited multiple incidences in which the source of contamination was identified, including an outbreak of cyclosporiasis that was associated with raspberries from Guatemala. There was also a similar illness in children in Guatemala linked to unsafe drinking water. The investigation took months to develop. “The source of contaminated food may not be immediately obvious,” Tauxe said.

Alejandro Castillo, PhD, associate professor in the department of animal science and member of the graduate faculty of food science at Texas A & M University in College Station, agreed. “By the time you detect an outbreak, study it, trace it back to the source and conduct on-site investigations, there is no evidence left,” Castillo said. “All they have to determine what happened is records. When we conduct such investigations, we should not expect to find a smoking gun.”

Even when the source is immediately obvious, or perhaps especially when the source is immediately obvious, it is still difficult to solve problems and institute controls. Both Doyle and Jaykus cited aquaculture practices, specifically in Asian countries.

“We have seen a problem with chicken and shrimp farming in Thailand,” Doyle said. “The chicken coops sit over the water above the shrimp farms. The shrimp are being fed by chicken manure falling from above.”

U.S. organizations cannot possibly control all such practices. Jaykus surveyed data on seafood imports finding that one of the biggest concerns at the moment is salmonella contamination of seafood. Despite the low inspection rates, an alarming percentage of shrimp coming into the United States is contaminated with salmonella.

“And that is just the product we are testing,” Jaykus said. “Who knows what is the microbial status of seafood not being tested?”

Challenges

“They do not have the regulations or the inspections that we have in this country. It becomes an issue of equivalence of safety. Products coming from these countries are produced and processed using standards that are not necessarily equivalent to those of the United States,” Jaykus said in an interview with Infectious Disease News.

One safety issue Jaykus discussed was the presence of veterinary drug residues in seafood. “We are finding microbial antibiotic resistance in the seafood coming into the United States,” she said. “The genes involved in these drug-resistant microbes tend to be somewhat promiscuous in that they can jump from one species of bacteria to another. We may be setting ourselves up for a gradual dissemination of antibiotic resistance in a wide population of bacteria.”

On a larger scale, Jaykus discussed global climate change as having a huge influence on food contamination, particularly that of seafood.

Castillo focused a large portion of his presentation on contamination of produce coming from Mexico, where the United States has some degree of control over food safety procedures. But even where food safety programs are in place and strictly applied, contamination can occur. Castillo discussed incidences of E. coli and salmonella that stemmed from Mexican cantaloupes. They were grown and harvested in accordance with specifications, and testing showed them to be free of these contaminants; however, during washing and packing they became contaminated and then shipped again following specifications but potentially containing pathogens. Similar scenarios may have led to repeated outbreaks that led to the closure of U.S. borders for the Mexican and Honduran cantaloupe.

Investigation

Donald Schaffner, PhD, extension specialist in food science and professor at Rutgers, The State University of New Jersey, stressed the importance of mathematical models in monitoring and predicting cross-contamination and potentially hazardous foods. He cited an instance in which graphs of pH levels helped determine the rate at which salmonella grows and another instance in which a graph helped determine the temperature at which Clostridium perfringens germinates.

Schaffner focused largely on food production and contamination factors, but he was quick to note that mathematical models can be predictive in the area of public health as well.

“The real reason for developing certain models in the first place was to understand how important delays are in the public health system and how important those delays are in making a decision to issue an advisory,” he said. “Mathematical models on the total number of exposures in a given outbreak, the number averted by advisory, the number that are symptomatic, the number that are asymptomatic, the number of people who do not seek treatment, the number of confirmed cases, the day at which the advisory was issued, the day of last exposure and the day the incident was over — all can be helpful in aiding clinical practice and treatment.”

All of the experts, in one way or another, echoed his sentiments.

“The best source of information is outbreak investigations,” Tauxe said.

However, all also agreed that the overwhelming nature of the problem of food contamination has made it difficult to have a complete understanding of the food-related outbreaks happening around the world.

Responsibility

All presenters agreed that the bulk of the responsibility for instituting food sanitation standards falls on the United States, in spite of the overwhelming challenges. The FDA recently released a Food Protection Plan Progress Report as a follow-up to the Food Protection Plan of 2007.

The objective of the plan is to provide a framework for enhancing the safety of the food supply coming into the United States.

In the progress report, FDA officials said they are working with Chinese officials to establish a bilateral mechanism to help ensure imported products meet standards for safety and effectiveness by building quality into the process from the start.

Improvements in screening for and detection of contaminants in food coming from abroad are being put into place. This includes an increase in food inspection personnel at the federal and state level. The FDA also plans to develop more effective ways to respond to and investigate outbreaks. – by Rob Volansky

For more information:

Schaffner D. Fighting microbial innumeracy: life as a predictive microbiologist.

Doyle M. Global issues associated with the microbial safety of food.

Tauxe R. The epidemiology of food safety and its global impact.

Jaykus L, Castillo A. Microbial food safety and seafood.

All presented at: The 108th General Meeting of the American Society for Microbiology; June 1-5, 2008; Boston.