Planning for Prevention: Fresh Produce Safety from Pre-Planting through Production

by Shari L. Plimpton, Ph.D.
April 2004

In my travels around Ohio as a food safety educator, I enjoy the privilege of visiting a variety of fresh produce farm operations from orchards to muck crop growers. Occasionally I am greeted by a grower who wants to focus our consultation on the packinghouse. I will grant that most growers have reason to be proud of their efforts to handle produce safely postharvest. However, while it is true many elements of a safe produce growing operation originate within the packing house, we are missing some of our best opportunities to prevent foodborne illness if we ignore pre-plant and production practices.

When food safety educators present Good Agricultural Practices and Good Handling Practices (GAPs and GHPs,respectively), we all emphasize and repeat (to the point of boring the audience) that fresh produce food safety is based on Prevention, Reduction, and Education. I like to emphasize prevention based simply on common sense: the less likely microorganisms and other hazards are present on the produce, the less likely they will be able to slip through defenses in the packinghouse.

When looking for opportunities to reduce your risk from pre-planting through production look hard at the following potential risk areas:

• Manure/fertilizer use;

• Water (including spray and irrigation methods);

• Worker Health and Hygiene;

• Pesticide Management; and

• Animal and Pest Control.

Consider each of these basic areas in terms of potential for contamination as you review your pre-planting and production practices. Pathogenic microorganisms (the ones that can make people sick) tend to come from soil, fecal (animal or human) contamination, humans, rodents, or insects. Also, keep things in perspective and recognize that we are looking for practical ways to minimize risk. Total elimination of the risk is not practical; therefore, it is not our goal.

Manure can be a source of contamination, although, it is obviously not a concern for all growers. If you are using manure, recognize that you are handling a potential source of contamination which, when managed properly, will pose little risk to fresh produce. Composting, incorporation, and timing are the keys to using manure safely. Composting is preferred since high temperatures and aerobic conditions will kill most pathogenic microorganisms. Preferably, apply manure in the fall or at least two weeks before planting. At the minimum, allow 120 days from the time manure is applied to the date of harvest.

If you don’t use manure, do not assume your risk from fertilizer use is non-existent. Be aware of whether the fertilizer you are using includes any form of municipal biosolids. If so, get certification of the treatment process and a statement of guarantee that the waste has been processed in such a way as to eliminate the potential for pathogenic contamination.

Water is one of the more important potential vectors for contamination of fresh produce. First consider your source of water and the water quality. Surface water sources (lakes, ponds, streams, rivers, etc.) are a particular concern as are reservoirs of rainwater. Wells should be evaluated for potential leaks that may result in siphoning and backflow, as well as, the potential for surface water contamination. Testing water for coliforms (recommend <100 cfu/ml) and E. coli (recommend negative) as indicators of pathogenic contamination is an option to consider. Also, consider the risks that may be associated with fertilizers or sprays as a result of mixing with water. Black flow valves are critical to preventing chemical, as well as, microbial contamination and maintaining the quality of your water source. Treatment method of the water with chlorine or another type of sanitation method should be considered if you detect the risk of microbial contamination.

The other area of evaluation I like to emphasize is worker health and hygiene, including the use of sanitary facilities. Human contamination is a possibility usually through sprays workers have inadvertently contaminated or unsanitary practices in the field. Encourage workers to report health problems, and have alternative work available for those who are sick and could come in contact with the produce in the field. Also, make clean, sanitary facilities available very near the field and include some way for workers to wash their hands and provide single use towels.

Training and education are our most powerful tools for preventing contamination from workers. Free worker training videos are available for Ohio growers via the Ohio Specialty Crop Risk Management Initiative. This Initiative is being cooperatively managed by Mid American Ag and Hort Services (MAAHS), the Center for Innovative Food Technology and Ohio State University Extension ABE Center in partnership with the United States Department of Agriculture's Risk Management Agency. Supervisory emphasis on sanitary worker practices and the use of posters as reminders help to reinforce food safety training. Free, laminated posters about proper hand washing and use of field sanitation are also available for Ohio growers by contacting MAAHS.

Finally a few words about pesticide management and pest control. Following the requirements for use and documentation for pesticide use is normally adequate for managing pesticides safely. It is simply important to remember that pesticides are a potential hazard and should be carefully managed to avoid contamination. Excluding animals and pests from the field is critical toward your bottom line just as it is for food safety. Animals and insects both are potential carriers of some foodborne illnesses.

Once again, we are recommending managing for preventing and reducing the risk as much as is practically possible. Each operation is unique and should be reviewed to determine the potential risks for foodborne illness in each of the critical areas discussed above.

Consultation for GAPs, developing food safety programs, and passing third party audits is available through CIFT. You can reach us by calling Shari L. Plimpton at 614-314-4627 or emailing us at foodsafety@eisc.org.

Good Agricultural Practices Articles...

• ABCs of GAPs

• Cleanliness is Next to Food Safety

• The Distant Sound of Drumming

• The Efficient Use of Chlorine and Other Sanitizers in Postharvest Fruit and Vegetable Operations

• The Elements of Produce Food Safety Programs

• GAPs in Organics: Fresh Produce Safety from Pre-planting through Production

• Handling Your Food Safety Risks

• Its Not All in the Bag

• Passing a Third Party Food Safety Audit

• Pest Patrol for Fruit and Vegetable Growers

• Planning for Prevention: Fresh Produce Safety from Pre-planting through Production

• So, Just How Clean is Your Water

• Sustaining Healthy Soil

• The Value of a Food Safety Plan

• Water, Water Everywhere

• Worker Hygiene Keeps Produce Clean