On the farm
On the farm – by David Kingham – Click for details


The Food Source Information Wiki was developed by Colorado State University (CSU), in collaboration with the Colorado School of Public Health (CSPH) and the Colorado Department of Public Health and Environment (CDPHE), as part of the Colorado Integrated Food Safety Center of Excellence. We welcome contributions from individuals or groups working in food production and food safety in the United States. If you would like to request an editor login or have any questions, comments, suggestions, please click here.


Basic and timely information on agricultural production practices for foods suspected or implicated during a foodborne illness outbreak will better equip outbreak responders to determine the cause of the outbreak and contributing factors. This information is vital for preventing further illnesses and outbreaks.


The goal of the Food Source Information Wiki is to provide public health professionals with rapid access to basic information on production practices and food distribution systems for a range of agricultural food products, from farm to fork. By centralizing this information and delivering it in a format that meets the needs of public health professionals, we aim to bridge an important knowledge gap and improve outbreak response nationwide.

Crop-specific information can be found on the individual crop articles on this site. Food safety issues common to most crops are below.

Good agricultural practices (GAPs) are the basic environmental and operational conditions necessary for the production of safe, wholesome fruits and vegetables.
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Food Safety

  • Food safety is a measure of risks to health by food, and safe food is free of biological, chemical, and physical hazards.
  • Foodborne illnesses from disease-causing biological agents (called pathogens) are the most prevalent.
  • Bacteria, viruses, and parasites are the most common pathogens.
  • Pathogens typically contaminate produce following contact with human or animal feces—directly or through tainted water, surfaces, or unhygienic workers.
  • Potential for contamination exists before, during, and after production and harvest, through processing, storage, and transport, and after delivery.
  • Particular areas of concern on the farm include management of water, agricultural chemicals, manure and municipal bio-solids, and activities of people and animals.


Whenever produce comes into contact with water, there is potential for contamination with pathogens. Agricultural water may come from a variety of sources, including groundwater, ponds, lakes, streams, wells, or municipal supplies. Water is used during several steps along the farm-to-table food chain, including: irrigation, application of pesticides and fertilizers, and during rinsing, cooling (including ice), washing, waxing, and transport. Factors which may contribute to water contamination include:

  • current and past land use, especially related to animal production, run-off, or chemicals,
  • animal access and/or distance from growing areas (related to the potential for fecal contamination),
  • well maintenance,
  • management of wash and processing water,
  • routines for the following procedures based on GAPs:
    • testing for microbes,
    • changing water and/or using filtering equipment to maintain safe coliform levels, depending on use,
    • maintaining water at appropriate temperatures, depending on the use,
    • inspecting and maintaining equipment used to ensure water quality,
    • keeping records of all testing and maintenance, and
    • making available an alternative emergency water source such as bottled water or a private source with routine disinfection and testing.

Maintaining record keeping and performing regular testing is often a challenge for farmers, and in a 2010 investigation by the Community Food Security Coalition, only about half of small farmers interviewed test water sources and/or maintain records.

Agricultural Chemicals

Improper use of fertilizers and pesticides may increase the potential for contamination of water and products.

  • Only properly trained, licensed employees who are aware of risks should handle any chemicals.
  • Application must be performed in accordance with manufacturer material safety data sheets and uses approved for the specific crop or situation.
  • Records of use must be maintained, including any equipment used for application or storage of chemicals.
  • If water or products are contaminated with chemicals, supervisors and qualified cleanup personnel should be notified so they can immediately dispose of the product and begin necessary remediation procedures.

Manure and Biosolid Wastes

Improper use of raw or untreated manure and certain biosolids may increase the potential for microbial contamination of produce.

  • Manure must be properly treated, composted, or exposed to UV light to reduce the levels of pathogens prior to application.
  • Appropriate time should be allowed to pass between application to production areas and crop harvesting. Typically application is in the fall, at the end of the season, post-harvest, but if it is done in the spring, it should be at least two weeks prior to planting or a minimum of 120 days before harvest.
  • Lagoons or areas designated for composting or storage of manure or biosolids must be maintained at a distance from crops to prevent outflow or leakage.
  • Growers should have knowledge of local topography and land use in order to assess how their land may be affected by management of these and other processes on adjacent lands or by weather, such as heavy rainfall.


Employees, volunteers, or customers, whenever human beings come in contact with food, there is potential for contamination with pathogens.

Employees, and anyone participating in the harvesting or handling of food, should have basic training in food safety, sanitation, and hygiene, including:

  • having good knowledge of hand washing techniques and washing hands prior to managing food and immediately after using the restroom, taking breaks, or engaging with animals,
  • being familiar with signs and symptoms of infectious disease and reporting to supervisors any illnesses or injuries that may be a risk for contaminating of food, and
  • not working if they have had diarrhea, symptoms of infectious diseases, or open wounds, which could contaminate food with blood or bodily fluids.

Some farms also have unique relationships with the public, such that people (other than trained employees) participate in food production, harvesting, sorting, packing, and transport. Others may allow customers into fields and orchards as part of U-pick operations, or they may have events, such as harvest festivals, or agri-tours—corn mazes, petting zoos, or pony rides where visitors are allowed to interact with livestock or other animals.

GAPs to minimize risks of contamination include:

  • keeping logs of all field visitors and maintaining visitor policies,
  • having clean, well supplied, regularly maintained/serviced, and accessible toilet facilities, with toilet paper, a sewage disposal system, and hand washing stations with soap, potable water, disposable paper towels, and lined and enclosed garbage containers, and
  • posting instructions reminding visitors to wash their hands (in the languages they speak).

Other policies to minimize hazards include prohibiting eating, smoking, and use of glass containers in any areas where product is handled and maintaining a log of illnesses, injuries, and any first aid provided to employees or visitors.

Animals: Wildlife, Livestock, and Domestic

Measures such as physical barriers and sound and odor repellents can be used to restrict animals from entering crop production areas, and hunting and human patrolling may be necessary to control some wildlife. Also, harvested products should be covered.

If visitors are allowed to bring dogs to the farm, policies should prohibit dogs from entering any areas where they could contaminate food, including crop production areas and food processing or storage areas.

Equipment, Storage, and Transport

Produce may be contaminated through contact with equipment and/or containers used during harvest, processing, storage, or delivery—including machinery, knives, tables, brushes, buckets, bins, boxes, pallets, and other containers. To minimize risks of product contamination, all of these items and all storage areas should be properly maintained in good repair, free of dirt and debris, and cleaned or sanitized between uses and on a scheduled basis. For larger containers, rooms, and vehicles such as trucks or trailers, this also includes surfaces such as floors, walls, and ceilings. Other GAPs include:

  • repairing damaged or worn out containers or, if they cannot be adequately repaired or cleaned and disinfected, they should be discarded,
  • avoiding contamination from any cleansers or pesticides used to control vermin such as mice or insects or from residues from previously stored or transported items,
  • maintaining adequate climate control as needed using, water, ice, or forced air to preserve optimal produce quality during storage, depending on the food,
  • keeping chilling equipment clean and sanitary,
  • maintaining records of crops held in storage before distribution.


Some products require processing, and steps must be taken to prevent contamination, including the maintenance of proper canning temperatures, pH, concerns related to water or additives used in processing, and containers and equipment, including jars and packing materials.

Record Keeping and Traceability

Should a food item become the suspected source of an illness outbreak, farm operators should have a protocol for tracing it back to its source, including documentation that enables them to trace the path of any product through the distribution channels from the farm field or orchard to the delivery location. GAPs include:

  • creating and maintaining farm maps and
  • keeping records of all produce grown and delivered—including:
    • crop/variety
    • location grown
    • date harvested
    • harvested by
    • locations stored
    • delivery date
    • transported/delivered by
    • transport conditions
    • delivery location


  • Grower’s Manual: A Template for Grower Cooperatives [Internet]. Leopold Center for Sustainable Agriculture; 2011 Oct. Available from: http://col.st/17cmWBN
  • Guide to minimize microbial food safety hazards for fresh fruits and vegetables [Internet]. U.S. Department of Health and Human Services, Food and Drug Administration, Center for Food Safety and Applied Nutrition (CFSAN); 1998 Oct. Available from: http://col.st/17crvMH
  • Markley K. Food Safety and Liability Insurance: Emerging Issues for Farmers and Institutions [Internet]. Community Food Security Coalition; 2010 Dec. Available from: http://col.st/17cnHeh
  • Jolly D, Lewis C. Food Safety at Farmers Markets and Agritourism Venues: A Primer for California Operators [Internet]. University of California Davis, Department of Agriculture and Resource Economics and UC Small Farm Center; 2008 Jul. Available from: http://col.st/17crkRe
  • Michigan State University Extension, Michigan Agricultural Cooperative Marketing Association Inc. Good Agricultural Practices (GAP) Assistance Manual [Internet]. 2011 Apr. Available from: http://col.st/17crVTf