Food Safety and Fresh Produce

Reprinted with permission from the Council for Agricultural Science and Technology
Appearing in Food Protection Trends, February 2004: 90-91

Recent outbreaks of food-related illnesses have increased many people’s concerns about the safety of fresh fruits and vegetables—regardless of whether the cause is hepatitis A, Escherichia coli (E. coli), or some other foodborne microorganism. These concerns already had increased during the past decade when, due primarily to an increased awareness of the health benefits fresh produce provides, people in the United States were eating more of these foods. Consumers in the United States expect to have a multitude of fresh produce available year round. To supply this demand, the produce industry has developed a distribution system to move both domestic and foreign produce to the dinner table.

The recent outbreak of hepatitis A in Pennsylvania, which killed three people and sickened more than 600, has raised new concerns about the safety of this supply and distribution system. The source of the outbreak was identified as green onions (scallions). As the story unfolds, can this tragic outbreak teach any valuable lessons about the safety of our food supply chain? Should other fresh produce items be avoided?

It is useful to remember that pathogenic (disease-causing) microorganisms are not part of the natural microorganisms found on or in fresh produce. Therefore, any disease-causing microbes present on fruits or vegetables are there because of inadvertent contamination, which can occur when produce comes in contact with dirty water, equipment, or storage containers; unsanitary human handlers and food preparers; and/or pests. Contamination can occur in the field or at any point in the food supply chain from production to table.

The fresh-produce processing industry uses various tools to decrease microbial contamination on products. Sanitary operating procedures common to the entire food processing industry include pest control, facility sanitation, worker hygiene, and temperature control. Fresh-produce processors often take specific steps to clean fruits and vegetables, including high-pressure washes, scrubbing, trimming, and peeling. Many processors, especially in the fresh-cut produce industry, also use sanitizing washes or dips to clean produce. These dips rely on chlorine or other sanitizers to kill harmful microbes. All the treatments, when properly applied, will substantially decrease—but may not eliminate—microbial contamination.

Consumers can take several actions to decrease their risk from disease-causing microbes on fresh fruits and vegetables. Because most microbial contamination is present on the skin or outer layers of produce, washing and peeling are effective ways to lessen the number of harmful microorganisms present.

• Wash produce with clean water before eating. (Household soaps and other cleansers are not recommended; they may not be effective in killing or removing pathogens and may leave harmful residue on the produce that poses a greater risk than any microbes potentially present.)

• Scrub firm produce, such as melons and cucumbers, with a produce brush during washing.

• Cut out damaged or bruised areas before eating.

• Control temperature of produce to prevent microbial growth.

• Refrigerate fresh produce that requires cool temperature (below 45°F, 7°C).

• Avoid leaving cut melons at room temperature for more than two hours.

• Wash hands and food preparation surfaces often.

• Avoid cross-contaminating ready-to-eat foods with raw meat, poultry, or seafood.

These techniques are highly recommended to enhance the safety of fresh produce, but may not be sufficient to remove all pathogens present. This is especially true for leafy greens and other hard-to-wash produce. The only sure way for consumers to eliminate harmful microorganisms in fresh fruits and vegetables is through cooking. Heating fruits or vegetables to a temperature of 160°F (71°C) or greater is enough to kill the pathogenic microorganisms that may be present. Of course, no one wants a cooked green salad. But folks who are particularly susceptible to foodborne illness—children, the elderly, and those with compromised immune systems—may want to avoid higher-risk fresh, uncooked produce.

Another lesson that may be lost in the clamor surrounding these events is that real health benefits come with a diet rich in fresh fruits and vegetables. But there also are real food safety risks and it is important to manage these risks, especially for particularly susceptible individuals. Consumers should be aware of outbreaks as they occur, heed official warnings, and follow good food-handling practices. With a little caution and common sense, we all can keep following Mom’s advice about eating fresh fruits and vegetables.