Foodborne illness & produce - EFR 6-18

We think of sauces, meats, eggs and other foods when we think about foodborne diseases. As the following points out, improper handling at different places in the processing of a food can also affect produce.

Excerpted from FOOD CHEMICAL NEWS, February 12, 1996, pp. 4-6

While outbreaks are few, the numbers are going up for foodborne illness associated with fresh produce according to Robert Tauxe, chief of the Foodborne and Diarrheal Diseases Branch in the Centers for Disease Control and Prevention. He was speaking to members of a fresh produce working group of the National Advisory Committee on Microbiological Criteria for Foods.

Tauxe referred to two CDC studies from 1973 to 1987 and 1988 to 1991 which identified- 103 outbreaks affecting 6,082 people. The rate of outbreaks went from 64 in 14 years to 39 in just 4 years. The number of cases also went up from 242 to 614 in the two studies.

Because of a short harvest, short shelf life and rapid turnover of fresh produce, it was possible to identify the source of foodborne outbreaks in less than 50% of the cases investigated by CDC, according to Tauxe. Tauxe reported that Salmonella accounted for 18% of the illnesses, while six other pathogens including Shigella, Staphylococcus aureus, Bacillus cereus and Hepatitis A were all in single digits and totaled 28% of the illnesses.

Melons and tomatoes containing Salmonella and Hepatitis A bacteria made up a large number of the outbreaks reported since 1997, reported Tauxe. Lettuce, apple cider, zucchini and green onions also were associated with recent foodborne outbreaks. Tauxe demonstrated the farm to table process fresh produce undergoes and noted that water posed a potential source of contamination in each step along the way.

Tauxe suggested some relatively simple steps that could be done now to decrease the potential to contaminate fresh produce:

* provide adequate field sanitation including hand-washing stations;

* add "barriers" to growth and survival of pathogens;

* clean dirt off produce;

* use chlorinated water in the processing stage, and

* use ice only from hyperchlorinated water for shipping, or switch to refrigerator trucks.

Tauxe called for some scientific initiatives that could be taken as well:

* Improving surveillance of foodborne outbreaks, including rapid electronic reporting and automated analysis to detect clusters.

* Conducting more applied research, which includes testing the efficiency of washing and decontamination of produce, developing better growth inhibition strategies and conducting surveys of contamination levels of local and imported produce.

At the discussion, Daniel Botts, director, Environmental & Pest Management Division, Florida Fruit and Vegetable Association, offered information that irrigation water is most likely the source of some contamination in fresh produce. Botts stated, "we share your concern and we need to put into practice something to prevent the problem."

Botts added, however, that most irrigation practices currently utilize a subsurface (deep well) or a directed-at-the-base-of- the-plant-type irrigation system. But he acknowledged that "run-off" water and other environmental factors do cause water problems.

He said a HACCP-like program makes sense during the distribution and shipment of fresh produce, but it is difficult to present a single program across all aspects like the growing, harvesting and processing of fresh produce because of the variety of different operations that are out there.

Botts did agree with Tauxe that field sanitation including the proper location and use of field toilets and hand-washing facilities, was an area where improvements were needed. Botts told FOOD CHEMICAL NEWS that the first step toward reducing the risk of contaminating fresh produce during harvesting is educating field workers as to the importance of field sanitation.