News Release

Report addresses safety problem in preharvest stage of food production

Peer-Reviewed Publication

American Society for Microbiology

WASHINGTON, D.C. – February 07, 2005 – Food in the preharvest stage is more vulnerable to contamination than food in the processing and packaging stages of production, because of environmental variability and our inability to control it, according to a new report released by the American Academy of Microbiology. The report, "Preharvest Food Safety and Security," points out that recent outbreaks of a number of foodborne illnesses have been linked to contamination occurring in the preharvest stage of food processing. The report recommends creating an accessible international database of genetic sequences for known foodborne pathogens along with new and improved tools for detecting and cataloging pathogens on the farm.

The report is based on the findings of a colloquium convened by the AAM in Perthshire, Scotland, in December 2003. Scientific professionals with expertise in veterinary medicine, agriculture, plant science, food safety, and microbiology met to discuss current practices in preharvest food safety, problems posed by pathogens on the farm, research needs in the field, and communication and education priorities.

"No matter how meticulously food is handled, prepared, or cooked, pathogens acquired during preharvest cannot always be inactivated," according to Colloquium Co-Chair, Richard E. Isaacson, Ph.D., of the University of Minnesota. Many foods have a higher risk because they are consumed raw, as was the case recently in Pennsylvania where 650 fell ill and 3 died from an outbreak of hepatitis A from contaminated green onions that originated in Mexico.

Elimination of all foodborne pathogens is impossible, but the goal of preharvest food safety is to reduce the risk of foodborne illnesses by minimizing the number of pathogens in food and the frequency, extent, and distribution of such contaminants in the preharvest phase. The report recommends systematic surveillance, detection methods, risk assessment, and trade issues as the areas that should be emphasized to ensure safety during all stages of food production. "We need to take into account the risks that pose the biggest threats to the greatest number of people, which include pathogenic viruses in the production of shellfish, parasites from free range meat and poultry, and bacterial foodborne pathogens introduced by humans and animals," according to Colloquium Co-Chair, Mary Torrence, D.V.M., Ph.D., of the U.S. Department of Agriculture.

Colloquium participants discussed establishing implementation guidelines for the best management practices at the farm. These guidelines will minimize the contamination of livestock that produce pathogens that cause disease in humans. The report also recommends establishing specific criteria to measure the efficiency of preharvest intervention strategies. Communicating to the public and educating them about preharvest food safety is essential. "The public should be more informed about preharvest food safety while understanding that zero risk is unattainable, according to the report."


To read a fully copy of the report and recommendations please visit the Academy online at or contact the American Academy of Microbiology at

The American Academy for Microbiology (AAM) is the honorific leadership group of the American Society for Microbiology. The mission of AAM is to recognize scientific excellence, as well as foster knowledge and understanding in the microbiological sciences. For more information about the American Society for Microbiology, contact Barbara Hyde at 202-942-9206 or visit

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