Occupational Health & Safety

Produce Safety: From the Ground Up

As mass manufacturing and processing of fresh produce increases due to demand and dietary recommendations to increase fruit and vegetable consumption, so may the risk from foodborne illness.

Momma said "eat your greens," and health professionals agree that the benefits of eating fresh fruits and vegetables far outweigh potential food safety risks. However, more and more Americans are concerned about getting sick from eating fresh produce. In National Public Radio's 2010 National Survey of Healthcare Consumers, approximately 24 percent of respondents indicated fresh produce poses the greatest risk for foodborne illness.

This concern is not surprising, given that in 2007, almost 25 percent of foodborne illness outbreaks were attributable to consuming fruits and vegetables (CDC, 2007). Leafy greens, cut tomatoes, and cut melons pose the greatest risk; they are responsible for 80 percent of the fresh produce outbreaks in recent years (FDA, 2010).

However, food safety risks from microbial pathogens, chemicals, or physical contaminants can be minimized along the chain of custody from farm to fork by implementing Good Agricultural Practices (GAPs) and Good Handling Practices (GHPs, pronounced GYPs). GAP-certified means that the farm operation has received a fee-based, on-site review provided by USDA’s Agricultural Marketing Service (AMS) or a private organization. Foodservice operators, especially those buying directly from local farms, should be familiar with the GAPs principles. The Food and Drug Administration's GAPs are based on eight principles, beginning with the source of water used for irrigation and washing freshly harvested produce.

Microbial pathogens that cause foodborne illness, such as Listeria spp. or Cryptosporidium, can be found in contaminated water. The quality of water needed depends on its intended use. Agricultural water, or water used for growing plants, may be of lower quality than drinking water (also known as potable water). Techniques such as drip irrigation help to minimize contact between the water source and the plant, but surface ponds or other water sources used for drip irrigation should be tested for fecal coliforms and generic E.coli.

It is important to recognize test results can vary from season to season, or even hour to hour, so consider when water is sampled for testing. For post-harvest washing, it is recommended to use water that is safe for human consumption. Water from a properly constructed, capped well should be tested at least annually for fecal coliforms to ensure it is safe for drinking. Documentation of the test results should be kept as part of the producer’s food safety plan. Municipal water sources do not have to be tested.

Principle two is proper manure use and handling. Microbial pathogens, such as E.coli O157:H7, often are found in animal manure. Farms using manure as a fertilizer should follow best practices to ensure pathogens are destroyed. Properly composted manure reaches temperatures between 130and 160 degrees F for five to 15 days (Cornell, 2003). This process should be documented as part of the farm’s food safety plan in the event records are needed to prove safe handling. If raw manure is used, it should be incorporated into the soil at least two weeks prior to planting or 120 days prior to harvest, according to Cornell University's National Good Agricultural Practices Program guide (Food Safety Begins on the Farm, 2003).

Employee Safety, Sanitation, and Training
Principles three, four, five, and six (worker health and hygiene, sanitary facilities, field sanitation, and packing facility sanitation) involve the safety and sanitation of workers and facilities. Recommendations to address these are similar to the standard operating procedures required by foodservice establishments.

Farms should supply toilet and handwashing facilities located near field harvesters or packing house employees. Reusable harvest containers should be cleaned after each load is delivered and before using again in the field. If harvest containers are stored outside, they should be cleaned and sanitized before being used to transport fresh produce. Procedures should be in place to prevent pest infestation, including birds, insects, and rodents, as these can contaminate product and packing containers. Household pets, such as dogs and cats, also should be excluded from growing and packing areas. Enclosed packing sheds provide additional control. Packing materials should be food grade and stored away from potential contamination by environmental and human elements.

All farm employees should be trained in safe food handling procedures, including handwashing and product handling. Gloves used by workers for planting or harvesting should not be worn for packing of washed product. This training should be documented.

Just think of all the ways workers could contaminate food in a production kitchen or manufacturing plant. Apply these thoughts to harvesters, and it becomes easier to understand how produce could become contaminated before it leaves the farm. If produce is sold as raw agricultural foods, farm workers are considered food handlers. Applying and documenting worker and facility safety and sanitation procedures helps ensure buyers that produce was grown and harvested according to GAPs.

Principle seven addresses transportation and involves the movement of produce from the farm to the end user and/or consumer. During transportation, produce should be held at temperatures recommended by post-harvest production guidelines for quality and safety. Monitoring temperatures during transport is also recommended, particularly because harvesting of many fresh produce items occurs in the hot summer months.

The University of California at Davis (UC Davis) Postharvest Technology Center provides produce fact sheets that inform growers and handlers of best produce handling practices (http://postharvest.ucdavis.edu/) along with many other valuable resources. Transport vehicles should be clean and free from potential cross-contamination sources, such as leaking refrigeration units or items previously transported. Produce should be loaded and unloaded carefully to prevent contamination or damage. If the outer skin of produce is broken, it becomes more susceptible to microbial contamination.

Finally, principle eight is traceability. Each entity along the supply chain should have the capability of tracking produce one link forward and one link backward. In other words, where did this product come from, and where did it go? This chain of custody must be maintained in the event of a food recall. Without it, the impact of a foodborne illness outbreak could be greater. Farms should maintain harvest records, including date of harvest, field identification, and names of harvesters. Produce distributors and cooperatives should maintain contact names of suppliers and customers, batch or lot identification, packing time if applicable, and provide tracking information if produce is commingled. Commingling produce from different sources into one pack or case interferes with traceability.

Requirements for Processors
Buyers are driving the GAP certification requirement of farms. If a farmer wants to sell blueberries to a national distributor or supermarket chain, he or she may be required to be GAP-certified by the buyer. Even buyers who purchase locally from small farms may require the farmer complete a GAP self-inspection. According to Dr. Cathy Strohbehn, an Iowa State University Extension specialist, GAP-based checklists have been developed by Iowa State to encourage growers and buyers to create on-farm food safety plans. More information, including presentations and publications that can be used in the development of an on-farm food safety plan necessary for GAPs review, can be found at www.iastatelocalfoods.org.

GAPs and GHPs are a proactive, voluntary food safety program in place for produce shipped directly from the farm to the market. In contrast, fresh-cut processors are required to implement HACCP (Hazard Analysis Critical Control Point) programs and conduct microbiological testing. Fresh-cut processors also may implement GAP requirements for fresh produce purchased from farms. Sales of fresh-cut produce have increased steadily in recent years. For example, supermarket sales for precut apple slices were up 13 percent in 2010 (UC Davis, 2011). FDA requires that fresh-cut processors follow the regulations outlined in the 2008 Guidance for Industry: Guide to Minimize Microbial Food Safety Hazards of Fresh-cut Fruits and Vegetables found at http://www.fda.gov/food/guidancecomplianceregulatoryinformation/guidancedocuments/produceandplanproducts/ucm064458.htm. Further, FDA was charged with developing specific growing and handling regulations for fresh produce as part of the 2010 Food Safety Modernization Act. These proposed regulations are expected to be released in 2012.

As mass manufacturing and processing of fresh produce increases due to demand and dietary recommendations to increase fruit and vegetable consumption, so may the risk from foodborne illness. Once produce is cut, conditions for microbial growth are ideal. The plants' natural barriers are broken down, and more simple nutrients are available to promote the growth of microorganisms that may be present. While the fresh-cut industry strives to mitigate foodborne illness through GHPs and produce applications or processes such as chlorine, ozone, and natural substances, almost 42 percent of the foodborne illness outbreaks in 2008 were related to fresh-cut produce (FDA, 2010).

In 2012, school meal programs will receive new meal pattern guidelines from USDA as part of the initiative to combat childhood obesity. Increasing the variety and amount of fresh fruits and vegetables served to children is just one of the expected requirements. Due to the large numbers of children, including the high-risk population of children in pre-kindergarten programs, USDA began research and training to ensure school foodservice operators have the knowledge and resources to handle fresh produce safely.

In 2011, USDA announced Kansas State University was selected to establish the Center of Excellence for Food Safety Research in Child Nutrition Programs. The center will provide research in produce safety, in light of increased fresh fruits and vegetables served in the National School Meals Programs. The center's director, Dr. Kevin Roberts, and Dr. Jeannie Sneed, head of the Department of Hospitality Management and Dietetics, are working with food microbiologist Dr. Kelly Getty to determine the efficacy of reducing microbial pathogens and extending the shelf life of fresh produce by applying substances such as produce washes and ozone to fresh produce in school foodservice operations.

Seeking a Produce 'Kill Step'
The produce and fresh-cut industry have focused a tremendous amount of energy in research aimed at growing, harvesting, and processing fresh fruits and vegetables safely. Researchers at Kansas State aim to provide recommendations for kitchen operators in the safe handling of produce after purchase. Foodservice operators and consumers today are seeking a produce "kill step" like the one provided by cooking raw meat, poultry, or eggs to the recommended safe internal temperature.

Fresh produce is often consumed in the raw form, so there is no step that destroys all potential microbial pathogens. Currently, the 2009 FDA Food Code requires produce to be rinsed under running, potable water prior to serving. Leafy greens, cut tomatoes, and cut melons should be held at or below 41 degrees F during holding and serving.

The USDA Food and Nutrition Service Office of Food Safety, in conjunction with AMS, began providing a week-long immersion course called Produce Safety University in 2010. According to Brenda Halbrook, director of the Office of Food Safety, the course is offered by invitation only to child nutrition professionals at the state and local levels. Participants are trained in selected topics, such as basic GAPs and GHPs, produce quality and receiving, applying GAPs and GHPs in school gardens, procurement, and safe handling of produce in foodservice kitchen facilities. The participants are encouraged to train others to extend the knowledge.

Although the week-long Produce Safety University course is not available to everyone, the FNS Office of Food Safety has worked with partners to make related resources available to the public. Videos and fact sheets on produce safety topics were developed in partnership with AMS and the National Food Service Management Institute at the University of Mississippi and are available at www.nfsmi.org/producesafety. The FNS Office of Food Safety also partnered with the School Nutrition Foundation to offer a four-part webinar series on produce safety in schools during school year 2011-2012. The first two webinars were held in fall 2011, and the recorded archives are available at www.schoolnutrition.org/schoolgardens and www.schoolnutrition.org/producepurchasing.

Billions of dollars are generated each year from the fresh produce industry, in addition to all of the health benefits from consuming five to nine servings of fruits and vegetables daily. By taking proactive steps in developing, implementing, and documenting food safety plans from the farm to the fork, risks from eating fresh produce could be greatly diminished. The associated costs for food safety programs, including GAPs and GHPs, are far lower than the potential price of loss of life or litigation down the road if an outbreak occurs. So listen to your momma and eat your vegetables -- just make sure you take steps to increase their safety.

This article originally appeared in the February 2012 issue of Occupational Health & Safety.

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