Human Pathogens and Fresh Produce: Prevention and Damage Control: Introduction to the Colloquium

Abstract

A few years ago, food safety in fresh produce was discussed primarily in terms of pesticide residues. The assumption was that human pathogens just weren’t found on fresh fruits and vegetables, at least not in the United States and Canada, where potable water and chemical fertilizers are used for most production. Suddenly, the produce industry found itself caught up in a new definition of food safety, that of the human disease-causing pathogens, that have plagued the dairy and meat industries. The assumption has been that the pH of fruits and vegetables generally is too low to support the growth of human disease-causing pathogens (Beauchat, 1996). The outbreaks of Escherichia coli O:157:H7 in nonpasteurized apple juice and cider, and the growth of Salmonella on tomatoes (Lycopersicon esculentum Mill.), indicate the need for more vigilant attention to production and handling practices. While the incidence of food pathogen outbreaks in fresh produce is still very low compared with that in other foods, the media attention focused on each new event sparked a new wave of consumer fear about the safety of agricultural commodities. Where did these organisms come from? Several theories have been advanced. One is that microbes have evolved to more pathogenic forms or to forms that can now survive under conditions that previously checked growth, like refrigeration and acidic substrates (Thayer and Reykowski, 1999). Changes in production practices and increased numbers of people handling the same produce may be other factors (Thayer and Reykowski, 1999). The United States and Canada supposedly have the safest food supply in the world. Certainly, this remains true, but the amount of negative publicity surrounding an outbreak can be devastating for both the individual producer and the industry as a whole. The intent of this colloquium is to better understand how these outbreaks occur, how illnesses are documented and traced back to a source, and how steps can be taken at the grower level to minimize the potential for contamination of fresh produce by pathogens causing disease in humans.