USDA has developed a third-party audit certification program for food safety on the farm. The major areas of concern on the farm include worker hygiene, water quality, manure and compost management, sanitation, traceability, and animal/livestock issues. In New England, some buyers are requesting and, in some cases, requiring that growers become certified in Good Agricultural Practices (USDA GAP or Harmonized GAP). GAP contains several levels of certification and individual buyers may request one or more levels. Levels include general farm questions, field harvesting and packing, packing shed, storage and transportation, and traceability. To become certified a grower needs to attend a GAP training program (consult Extension or your state Department of Agriculture), develop a farm plan which reflects all the levels that the grower wishes to become certified in, and successfully complete a third-party audit. The UMass website which contains the GAP and Harmonized GAP training materials can be found at http://ag.umass.edu/agriculture-resources/gap-manual or search for "UMass GAP."
Massachusetts has also developed a 3rd-party-audit sustainability standard known as Commonwealth Quality (CQP). CQP contains a food safety component that includes all of the major areas of GAP. Certain wholesale buyers will accept CQP as an alternative to GAP or Harmonized GAP. CQP also provides growers a food safety certification program to satisfy retail customer needs for food safety compliance. See www.thecqp.com
Following Good Agricultural Practices (GAP) is necessary to prevent microbial contamination of fresh produce, and to assure continued consumer confidence in fresh, local food. The following is adapted from the Cornell University pamphlet called Food Safety Begins on the Farm at http://www.gaps.cornell.edu/documents/edumat/FSBFEngLOW.pdf. These are the steps that farmers can and should take to minimize pathogen contamination during the production and harvest of fresh produce.
Select Your Produce Fields Carefully. Review the land history for prior use and possible applications of sludge or animal manure. Choose fields that are upstream from animal housings. Know what the upstream uses of surface water are, and test water quality as needed (for coliform bacteria in particular). Prevent runoff or drift from animal operations from entering produce fields by using sufficient separation, adequate buffer plantings, or other means.
Use Manure Properly. In the fall, if applying manure to planned vegetable ground, do so preferably when soils are warm (over 50º F), non-saturated, and cover cropped. In spring, incorporate manure at least two weeks prior to planting. Whenever possible, incorporate manure. Do NOT harvest produce within 120 days after fresh manure application. Keep records of all manure and fertilizer application rates, source, and dates. Avoid root / leafy crops if manure is applied in spring. Instead, plant field crops like small grains or perennial forages where manure is applied in spring.
Absolutely do not sidedress food crops with fresh solid manure or slurry manure or manure 'tea' or any mulches containing fresh manure. However, it is OK to sidedress with mature composts or compost teas. A mature compost is one that has been thoroughly heated, turned several times, and allowed to age for a long enough time that it is virtually odor-free and is not objectionable to handle with bare hands.
Exclude Animals. NO grazing of livestock should be permitted near produce fields. Minimize wild and domestic animal traffic in produce fields by use of fences, scare devices or other means.
Assure Irrigation Water Quality. Municipal drinking water is low risk. Potable well water is minimal risk if the well casing is maintained and livestock are excluded from the active recharge area. Surface water is higher risk and warrants more intensive testing. Test surface water quarterly or at regular intervals during the growing season (beginning, mid or high draw, and at harvest). Be especially sure to test your irrigation water if the source passes near livestock or sewage treatment. Maintain records of your water tests. Filter or use settling ponds to improve water quality if needed. Use potable water for crop protection sprays. Where feasible, use drip irrigation to reduce crop wetting and minimize risk. If applying overhead irrigation, try to do so early in the day so that leaves dry quickly.
Maintain Cleanliness During Harvest. Check that all harvest containers are clean and in good repair. High-pressure wash and sanitize harvest bins prior to the harvest season and clean bins daily during harvest. Remove excess soil from bins in field. Ensure that packing containers are not overfilled and protect produce adequately from bruising and damage. Avoid standing in the bins during harvest to reduce pathogen spread by shoes. Minimize bruising of produce during harvest. Remove excess soil from produce in the field.
Promote Worker Hygiene. Teach all your workers about microbial risks and the importance of good hygiene. Provide and maintain clean restrooms in or near the field and in food handling areas. Supply soap, clean water and single-use towels for hand washing, and enforce their use.
Promote Cleanliness at U-Pick. Invite customers to wash their hands prior to entering your fields. Provide clean and convenient restrooms. Supply soap, clean water and single-use towels, and encourage their use.
Keep Produce Cool. Cool produce quickly to minimize growth of potential pathogens. Use ice made from potable water. Store produce at appropriate temperatures to maintain good quality. Do not overload coolers.
Post-Harvest Handling. Use potable water for all produce washes. Maintain clean water in dump tanks by sanitizing and changing water regularly. Chlorinate wash water and monitor chlorine levels. Maintain 150 ppm of chlorine in the water for leafy vegetables and up to 500 ppm for other crops if conditions warrant. (Note: organic growers will have to dilute this water to 4 ppm prior to draining it in order to meet national standards, check with your certifier). Maintain water pH at 6.0 to 7.0 to assure that the chorine is effective. Provide a final rinse if using less than 100 ppm chlorine. Avoid tank water temperatures that are more than 10°F cooler than the temperature of the produce you are washing (so the produce won't absorb wash water into its tissue). Clean and sanitize loading, staging, and all food contact surfaces at end of each day. Take the steps necessary to exclude all animals, especially rodents and birds from the packing house. No smoking or eating should be allowed in the packing area.
Transportation and Refrigeration. Check and clean out trucks prior to loading them. Sanitize the truck if animals were previously hauled. Pre-cool vehicles prior to loading. Ensure that refrigeration equipment is working properly.
A practical GAPs self-assessment for farms, with worksheets that can be printed out, is at: www.gaps.cornell.edu/farmassessmentws.html. A very detailed self-audit for growers is at: http://onfarmfoodsafety.org/wp-content/uploads/ucdavis-food-safety-audit.pdf. The Guide to Minimize Microbial Food Safety Hazards for Fresh Fruits and Vegetables from the US Food and Drug Administration is at: http://www.fda.gov/downloads/Food/GuidanceComplianceRegulatoryInformation/GuidanceDocuments/ProduceandPlanProducts/UCM169112.pdf.