Produce Safety

Produce encounters opportunities for microbial contamination with fecal pathogens during growing, harvest, and distribution, whether through direct exposure to manure or through contact with contaminated water, soil, containers, equipment, or workers. Fresh produce is frequently eaten raw and may not undergo heating or other processing that would kill these pathogenic organisms. Preventing produce from coming into contact with these organisms is the best way to prevent foodborne illness related to fresh produce.

Good agricultural practices, or GAPs, are those practices that help to reduce exposure of produce to disease-causing microbes. GAPs should be focused on the key hazard areas described below. While the following information provides general guidance around these areas, be aware that regulatory requirements (discussed at end of section) set specific requirements for farms with respect to water quality, worker training, and other aspects of production and handling.

Agricultural Water

Water is used in many ways on a farm and is a primary vehicle for the movement of pathogens. Agricultural water can be divided into two categories: preharvest water and harvest/postharvest water. Preharvest water is water that contacts the harvestable portion of a crop and includes any water used for preharvest activities, including irrigation, crop sprays, or frost protection. Harvest/postharvest water is any water used during and after harvest and includes water used for produce washing, commodity movement, cooling, ice making, postharvest fungicide applications, handwashing, and cleaning and sanitizing of food contact surfaces.  In order to manage potential contamination, it is important to understand the risks associated with the source of your agricultural water and how the water will be used during preharvest and harvest/postharvest activities.

Water Source and Microbial Risk

Surface Water: Surface water, including rivers, streams, lakes, ponds, man-made reservoirs, and any other water source that is open to the environment presents the highest microbial quality risk. Water quality from surface water can vary greatly between sites and over time. Some major contamination risks include wildlife, water runoff from upstream livestock operations, and wastewater discharge.  Growers should assess the potential risks to each of their surface water sources.  Water testing (typically for generic E. coli as an indicator of fecal contamination) can be part of this assessment.  Talk to your local extension staff for how best to integrate these tests into your assessments.  Untreated surface water should never be used for postharvest activities.  When using surface water for pre-harvest activities, growers should use their risk assessments to implement the reduction strategies noted in the following section.

Ground Water: Ground water, or well water, poses less risk than surface water for agricultural uses, however hazards such as cracked well casings and leaky septic systems increase the risk that ground water can become contaminated.  Testing ground water for generic E. coli at least annually will help provide one measure that the ground water is of adequate quality to use in harvest/postharvest use (should have no detectable generic E. coli).  Regulatory requirements noted below require additional tests for harvest/postharvest water use.  For preharvest water use, implementing the risk reduction strategies noted below (e.g., use of drip irrigation) may not be necessary for food safety but may have add-on effects such as reducing the spread of plant pathogens and the amount of water used.

Public Water Supplies: Public water supplies are monitored and treated by municipalities and therefore pose the least risk, although water still may become contaminated within your distribution system.

Water Use Risk Reduction Strategies

During growing, all farms should keep potentially high-risk water from contacting the harvestable portion of a crop. Example risk reduction strategies include protecting water sources from potential contamination (e.g., by installing barriers such as berms or vegetative buffers), switching from overhead irrigation to drip irrigation, or increasing the amount of time between application of water and harvest of the crop.

For postharvest applications, risk-reduction strategies include using single-pass water (e.g., spray from a hose, conveyer, or barrel washer) instead of recirculated or batch water (e.g., from a recirculating conveyor or dunk tank). Recirculating water can become contaminated and present a cross-contamination risk, and if it is used it should be changed frequently enough that it remains of adequate sanitary quality for its intended use. Sanitizers labeled for use in produce wash systems can help reduce the risk of cross-contamination in recirculated or batch water and can help reduce the build-up of microbes and biofilms on food contact surfaces. Be aware, though, that sanitizers are pesticides and must be labeled for their intended use and handled and monitored carefully while following your state’s pesticide regulations. In particular, some sanitizers are labeled for use in produce wash water while others are labeled for use on food contact surfaces. In some cases the same product can be used for either purpose, but the concentrations and use instructions are different.

Worker Health, Hygiene, & Training

People can easily move pathogens around the farm and onto produce through dirty hands, footwear, and clothing. Good hygiene and regular, proper handwashing can prevent produce contamination. Make clean, well-stocked, readily accessible toilets and handwashing stations available to workers and farm visitors at all times. Ensure that anyone working around produce maintains personal cleanliness and that all employees know how and when to wash their hands.  Ensure that employees and visitors are aware of the signs of foodborne illness and that anyone with illness symptoms does not work around food or food contact surfaces.

Educate your employees with the information they need for their particular job regarding food safety and empower them to make informed decisions about contamination risks. An employee who only harvests produce will need different information than an employee who works full time in the wash/pack area. Ensure that your employees know how to identify potentially contaminated produce or food contact surfaces and know what to do if produce becomes contaminated or if they or another employee is sick.

Postharvest Handling & Sanitation

Good housekeeping in wash and pack areas can help prevent produce from becoming contaminated. Keep postharvest areas clean and organized and encourage workflow that reduces overlap between washed and unwashed produce, containers and equipment. Keep produce handling areas separate from other farm activities such as tractor repairs, pesticide mixing, or employee break areas. Do not store sanitizers where they could spill on produce.  Bacteria thrive and multiply in water, so allow equipment to dry and minimize standing water with good drainage and/or by routinely clearing pooled water. If your packing area is outside, be sure that area drains well. A gravel pad can help with drainage and soil splash. Keep pests from entering produce wash, pack, and storage areas and establish a pest management program, if necessary. 

In addition to general cleanliness, it is important to know how to clean and, when necessary, sanitize tools, equipment, and surfaces effectively. While cleaning and sanitizing should be focused on food contact surfaces—any surface that comes into physical contact with produce—you should also clean “secondary” surfaces that may indirectly contact food or food contact surfaces. 

Cleaning and sanitizing refer to separate actions. Cleaning is the physical removal of dirt and organic matter from surfaces, using water and a detergent. Sanitizing is the treatment of a cleaned surface to reduce bacterial pathogens to a level considered safe as judged by public health entities. A dirty surface cannot be sanitized—cleaning always comes first. Disinfection is a process used to destroy or irreversibly inactivate bacteria, fungi and viruses, but not necessarily bacterial spores. A disinfectant would typically only be used if a surface were known to be contaminated by blood or other bodily fluids. In that case, after disinfecting with a product labeled for disinfection, and if the surface is a food contact surface, the surface should be rinsed with potable water then sanitized again.  This is because disinfectants are strong and can themselves become a food contaminant if not used according to the label.

Soil Amendments

Food safety risks regarding soil amendments generally involve application of raw manure, or other untreated animal-based soil amendments during growing. All animal-based soil amendments can contain pathogenic microorganisms if they are not processed in a way that kills such pathogens. If you use composted manure on your farm, you need to ensure that the manure is composted correctly and fully to be considered mature compost. A mature compost is one that has been thoroughly heated and allowed to age for a long enough time that it is virtually odor-free and is not objectionable to handle with bare hands. FDA specifies 2 processes that have been validated for this purpose:

  • Static composting: a pile must reach a minimum of 131ºF for 3 consecutive days, followed by curing, and
  • Turned composting: a pile must reach a minimum of 131ºF for 15 days with the pile turned at least 5 times, followed by curing.

Other methods may also achieve adequate pathogen reduction but should be scientifically validated. If compost is not matured properly, it should be handled and applied as if it were raw manure. 

In the fall, if applying manure to land in food production, do so preferably when soils are warm (over 50ºF), non-saturated, and cover-cropped. The rest of the year, incorporate manure whenever possible. Maximize the time between application of manure and harvest—a good guideline is the National Organic Program Standard of a 90-day interval for crops that do not touch the soil and 120 days for crops that do. Keep records of all manure and fertilizer application rates, source, and dates. Avoid planting root or leafy crops if manure is applied in spring. 

Never side-dress food crops with fresh solid manure, slurry manure, manure 'tea' or any mulches containing fresh manure. However, it is ok to side-dress with mature compost. If you do not have records or certification that compost was properly treated to control pathogens, handle it as if it were raw manure and observe the suggested 90/120-day application interval.

Wildlife, Domesticated Animals, & Land Use

Animals on farms can pose food safety concerns because they can carry certain human pathogens (e.g., Salmonella, Listeria, and E. coli) and can spread those pathogens through fecal matter directly to produce in fields, or indirectly through water sources or by contaminating food contact surfaces. Avoid grazing livestock near produce fields and keep pets out of production areas. Assess risks posed by livestock on adjacent land. It is impossible to exclude all wildlife from produce fields but minimize wild and domestic animal traffic by use of fences, scare devices or other means. Consider berms to prevent runoff entering a produce field. Have a plan for how you will manage fecal contamination when it happens. Never harvest produce that is or that you suspect to be contaminated with animal excrement.

Farm Food Safety Plans & Traceability

Accurate recordkeeping and documentation of practices are important for ensuring that the risk management strategies described above are done consistently and effectively. There are many recordkeeping templates available through resources such as the Produce Safety Alliance or other Extension programs. A farm food safety plan can help you to compile relevant food safety documents such as risk assessments, standard operating procedures, training information and record keeping logs that can help you identify areas on your farm that pose the greatest risk and address them. A food safety plan may also be required by buyers or third-party food safety audit programs.

Your plan may include a traceability program to help you track your produce one step forward and one step back within the distribution chain in order to quickly respond in the case of a foodborne illness incident. Tracking produce requires the definition of a “lot” or distinct and limited portion of a crop and a code for identifying that lot. Lot codes should be a unique code for the identifying characteristics of a lot—for example, the crop and variety name, field or block of origin, and the harvest and packing date. This code will help you identify a particular lot once it has been sold in case you wish to remove your product from the market for any reason, as well as describe it with important information that may help in the case of an investigation. 

Produce Safety Regulatory Requirements

In 2011, Congress passed the Food Safety Modernization Act (FSMA), which focuses on preventing contamination within the food supply. It required FDA to set rules that apply to different sections of the food system, including the Produce Safety Rule, which sets standards for the growing, harvesting, packing, and holding of produce for human consumption.  The Produce Safety Rule includes a set of requirements to address the hazards listed above.

FSMA’s Produce Safety Rule is enforced at both the federal and state level, and each of the six New England states has its own enforcement model.  Contact the agency in your state for more information on food safety regulations and best practices, and your responsibilities under FSMA:

Connecticut: Connecticut Department of Agriculture
Maine: Maine Department of Agriculture, Conservation and Forestry 
Massachusetts: Massachusetts Department of Agricultural Resources
New Hampshire: New Hampshire Department of Agriculture, Markets, and Food
Rhode Island: Rhode Island Department of Environmental Management
Vermont: Vermont Agency of Agriculture, Food & Markets

You can also refer to the FDA’s Final Rule on Produce Safety or contact your state Extension for more information on the FSMA Produce Safety Rule standards.

Food Safety Audit Programs

In New England, buyers are requesting and, in some cases, requiring that growers be certified by a 3rd-party audit program to demonstrate that they are following GAPs. Examples of these programs include the USDA’s Basic GAP and Harmonized GAP audit programs, as well as state-specific programs, including CGAP (Connecticut), Commonwealth Quality or CQP (Massachusetts), RI GAP (Rhode Island), and Community Accreditation for Produce Safety or CAPS (Vermont).  Your state extension office would be a good source of information about the options available to farmers in each New England State.