While the United States enjoys one of the safest food supplies in the world, the Centers for Disease Control and Prevention (CDC) estimates that one in six people get sick from a foodborne illness each year, with fresh produce accounting for nearly half of these illnesses. Produce encounters many 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 so may not undergo heating or other processing that would kill 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. In New England, buyers are requesting and, in some cases, requiring that growers become certified by a 3rd-party audit program to demonstrate that they are following GAPs. Examples of these programs include the USDA’s GAP and Harmonized GAP audit programs, Commonwealth Quality (CQP) in Massachusetts and Community Accreditation for Produce Safety (CAPS) in Vermont.
In 2011, the Food & Drug Administration passed the Food Safety Modernization Act (FSMA), which focuses on preventing rather than responding to contamination within the food supply. It consists of seven major rules, including the Produce Safety Rule, which sets standards for the growing, harvesting, packing, and holding of produce for human consumption. This rule is the one most likely to impact fruit and vegetable growers. It became final in January 2016. Compliance was phased in for affected growers, depending on their annual produce and food sales. This phasing in process began in 2018, but some portions of the rule are under review. If you are unsure where your farm falls under this rule visit UNH or UMass Extension’s online tool (link is external) or contact your local Extension representative.
FSMA’s Produce Safety Rule is enforced at the state level, and each of the six New England states has its own enforcement model. Responsible agencies are listed below. 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
Efforts to prevent contamination of produce should be focused on the following key hazard areas. Be aware that FSMA’s Produce Rule sets specific requirements for covered farms with respect to water quality and testing, worker training, and other aspects of production and handling. For all other farms, the rules and information about hazards can serve as best management practice recommendations. Refer to the FDA’s Final Rule on Produce Safety or contact your state Extension or responsible regulatory agency for more information.
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 groups: production water and postharvest water. Production water is water that contacts the harvestable portion of a crop and includes any water used for irrigation, crop sprays, or frost protection. 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.
Consider the source of your agricultural water and how the water will be used in order to manage potential contamination. Surface water, including rivers, streams, lakes, ponds, man-made reservoirs, and any other water source that is open to the environment, is subject to the highest 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. Untreated surface water should never be used for postharvest applications and should be monitored carefully when used as production 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. 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. It is important to be aware of the risks to the microbial quality of agricultural water and to keep contaminated water from contacting produce.
Routinely test agricultural water for generic E. coli (an indicator of fecal contamination) to get a measure of its microbial quality. Test both at the source and at the output to test for contamination within the distribution system. Post-harvest water should have 0 CFU generic E. coli per 100 ml sample. For pre-harvest agricultural water, there is currently no specific microbial standard set by FSMA regulations or the USDA GAP audit programs. Some other audit programs may have their own standards. Historically, FDA and USDA have used the EPA's standard for recreational water (a geometric mean of 126 CFU generic E. coli per 100 ml sample) as a basis for pre-harvest agricultural water criteria. Growers should routinely test their agricultural water, aim to keep E. coli levels as low as possible, look for spikes and trends in test results to identify increased risks of fecal contamination, and address those risks. Keep potentially high risk water from contacting the harvestable portion of a crop. Example risk reduction strategies are to switch from overhead irrigation to drip irrigation, or for postharvest applications, use 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 or 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.
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 house. 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 it would 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.
Food safety risks regarding soil amendments generally involve raw manure, or other untreated animal-based soil amendments. 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. Otherwise, it should be used as 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. 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. If you do not have records or certification that compost was properly treated to control pathogens, handle it like 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. 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 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 essential 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 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.