Outbreaks of foodborne illness make news headlines on a regular basis. In the U.S., it is estimated that as many as 76 million people contract some type of foodborne illness each year. As a result, over 325,000 are hospitalized, and about 5,000 deaths occur. Salmonella on tomatoes and cantaloupes, E. coli 0157:H7 on lettuce and in apple juice, hepatitis A on strawberries, and Cyclospora on raspberries have shaken consumer confidence in the safety of fruits and vegetables. Since 1987, the number of produce-associated outbreaks has doubled, raising concern among the produce industry, government agencies, and consumers. Food Safety Begins on the FarmBy Anu Rangarajan, Marvin Pritts, Steve Reiners, and Laura Pedersen, (updated with assistance from Victoria Zeppelin and GAP’s team), Department of Horticulture, Cornell University.
From planting to consumption, there are many opportunities for bacteria, viruses, and parasites to contaminate produce. On the farm, soil, manure, water, animals, equipment, and workers may spread harmful organisms. Produce may be harvested on a farm, processed in one plant, repackaged in another, then stored, displayed, or served by an institution or in the home. Each of these steps is an opportunity for harmful microorganisms to enter the food supply.
How much foodborne illness originates on the farm? No one knows. Are there reasonable steps that a grower can take to reduce the risk that pathogens will contaminate the food produced on the farm? Absolutely.
Clean Soil
The improper use of manure can be a risk factor contributing to foodborne illness. Pathogens such as E. coli 0157:H7, Salmonella, and Campylobacter can be present in manure slurry and soil for up to 3 months or more, depending on temperature and soil conditions. Listeria can survive on vegetables growing in the soil, even though it may not survive in the soil itself. Yersinia can survive in soil for up to 330 days. Composting manure, incorporating it prior to planting, and avoiding top-dressing with fresh manure are important steps that can reduce the risk of contamination while making use of this important source of nutrients. Excluding domestic and wild animals as much as possible from production fields will help reduce the risk of manure (fecal) contamination.Clean Water
When using surface water for irrigation, test quarterly for fecal coliforms, especially if water passes close to sewage treatment or livestock areas. Make sure that water used for produce cooling, washing, dipping, and processing operations is drinkable (potable). Whenever possible, use chlorinated water. Always make ice with potable water.Clean Hands
Attention should be paid to worker hygiene in the field and the packing house. Workers who pick, sort, grade, or pack produce must wash their hands after using the restroom. Hepatitis A outbreaks have been linked to infected workers. Teach workers about microbial risks. Provide soap, clean water, and single-use towels in the field, and insist that all workers wash hands before handling fruits and vegetables.Clean Surfaces
Before harvesting or packing and at the end of each day, clean all bins and work surfaces. Sanitize surfaces using recommended chemicals and procedures (consult local Extension Service for specific recommendations).This is no way to guarantee that everything we grow and consume is free of harmful microbial contamination. This risk can be reduced if preventative steps are taken before produce leaves the farm.
This article appeared in the February 2001 issue of Vegetable Production & Marketing News, edited by Frank J. Dainello, Ph.D., and produced by Extension Horticulture, Texas Agricultural Extension Service, The Texas A&M University System, College Station, Texas.