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  A Publication of UVM Extension's Vermont Vegetable and Berry Program

Minimizing Microbial Food Safety Hazards

by Vern Grubinger
Vegetable and Berry Specialist
University of Vermont Extension
Adapted from: US Food and Drug Administration voluntary guidance to individual growers, packers, and shippers of unprocessed or minimally processed or raw fresh fruits and vegetables

Agricultural Water: Identify source and distribution of water used. Be aware of current and historical use of land. Review existing practices and conditions to identify potential sources of contamination. Consider practices that will protect water quality. Maintain wells in good working condition. Consider practices to minimize contact of the edible portion of fresh produce with contaminated irrigation water. Where water quality is good, risk is low regardless of irrigation method.

Processing Water: Maintain water quality, such as by periodic testing for microbial contamination, changing water regularly, and cleaning  and sanitizing water contact surfaces. Antimicrobial chemicals may help minimize the potential for microbial contamination to be spread by processing water; levels of antimicrobial chemicals should be routinely monitored and recorded to ensure they are maintained at appropriate levels. As organic material and microbial load increase, the effectiveness of many antimicrobial chemicals will decrease. Filtering recirculating water or scooping organic material from tanks may help reduce the build-up of organic materials.

Cooling Operations: Maintain temperatures that promote optimum produce quality and minimize pathogen growth. Keep air cooling and chilling equipment clean and sanitary. Keep water and ice clean and sanitary. Manufacture, transport, and store ice under sanitary conditions.

Manure: Properly treated manure can be an effective and safe fertilizer. If manure is used as a fertilizer, it should be managed to minimize microbial hazards. Use treatments to reduce pathogens in manure and other organic materials. Treatments may be active (e.g., composting) or passive (e.g., aging). Manure treatment and storage sites close to fresh produce fields increase the risk of contamination. Consider factors such as slope and rainfall and the likelihood of runoff into fresh produce production areas. Use barriers or physical containment to secure storage and treatment sites. Protect treated manure from being re-contaminated. When purchasing treated manure, get information about the method of treatment. Maximize the time between application of manure to production areas and harvest. Use of raw manure on produce during the growing season is not recommended.

Animal Feces: While not possible to exclude all animal life from fresh produce production areas, many field programs include elements to protect crops from animal damage. Domestic animals should be excluded from fields and orchards during the growing and harvesting season. Ensure animal waste from adjacent fields, pastures, or waste storage facilities does not contaminate fresh produce production areas. Where necessary, consider physical barriers such as ditches, mounds, grass/sod waterways, diversion berms, and vegetative buffer areas.

Control of wild animal populations may be difficult or restricted by animal protection requirements. However, to the extent feasible, where high concentrations of wildlife are a concern, consider practices to deter or redirect wildlife to areas where crops are not destined for fresh produce markets

Worker Health and Hygiene: Infected employees who work with fresh produce increase the risk of transmitting food borne illness. Train employees to follow good hygienic practices. Establish a training program directed towards health and hygiene that include basics such as proper hand washing techniques and the importance of using toilet facilities. Become familiar with typical signs and symptoms of infectious diseases. Offer protection to workers with cuts or lesions on parts of the body that may make contact with fresh produce. If employees wear gloves, be sure the gloves are used properly and do not become a vehicle for spreading pathogens. U-pick and road-side produce operations should promote good hygienic practices with customers that encourage hand washing, provide toilets that are well equipped, clean, and sanitary and encourage washing fresh produce  before consumption.

Sanitary Facilities: Poor management of human and other wastes in the field or packing facility increases the risk of contaminating fresh produce. Be familiar with laws and regulations that apply to field and facility sanitation practices. Toilet facilities should be accessible to workers, properly located, and well supplied. Keep toilets, hand washing stations, and water containers clean and sanitary. Use caution when servicing portable toilets to prevent leakage into a field Have a plan for containment in the event of waste spillage.

Field Sanitation: Fresh produce may become contaminated during pre-harvest and harvest activities from contact with soil, fertilizers, water, workers, and harvesting equipment. Clean harvest storage facilities and containers or bins prior to use. Take care not to contaminate fresh produce that is washed, cooled, or packaged. Use harvesting and packing equipment appropriately and keep as clean as practicable. Assign responsibility for equipment to the person in charge.

Packing Facility: Maintain packing facilities in good condition to reduce the potential for microbial contamination. Remove as much dirt as practicable outside of packing facility. Clean pallets, containers, or bins before use; discard damaged containers. Keep packing equipment, packing areas, and storage areas clean. Store empty containers in a way that protects them from contamination.

Pest Control: Establish and maintain a pest control program. Block access of pests into enclosed facilities. Maintain a pest control log.

Transportation: Proper transport of fresh produce will help reduce the potential for microbial contamination. Good hygienic and sanitation practices should be used when loading, unloading, and inspecting fresh produce. Inspect transportation vehicles for cleanliness, odors, obvious dirt and debris before loading. Maintain proper transport temperatures. Load produce to minimize physical damage.

Traceback: The ability to identify the source of a product can serve as an important complement to good agricultural and management practices. Develop procedures to track produce containers from the farm, to the packer, distributor, and retailer. Documentation should indicate the source of the product and other information, such as date of harvest, farm identification, and who handled the produce. Growers, packers and shippers should partner with transporters, distributors and retailers to develop technologies to facilitate the traceback process. Once good agricultural and management practices are in place, ensure that the process is working correctly. Without accountability, the best efforts to minimize microbial contamination are subject to failure.

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