It’s Not Easy Bein’ a Green: Tips on Optimizing Leafy Green Safety

Their peer-reviewed document, “Recommendations for Handling Fresh-cut Leafy Green Salads by Consumers and Retail Foodservice Operators,” appeared in the November 2007 issue of Food Protection Trends, published by the International Association for Food Protection (Des Moines, Iowa).

“The expert panel achieved its goal,” says Larry Kohl, senior director of food safety for the Food Marketing Institute. “Their review of current science led to viable recommendations that are needed by consumers and the retail and food service industries.”

The National Restaurant Association (NRA; Washington, D.C.) has already implemented the recommendations in its ServSafe educational programs for food service workers, according to Donna Garren, PhD, NRA’s vice president of health and safety regulatory affairs. “We have expanded our references on how to handle produce in the back of the house,” Dr. Garren explains. “We stay vigilant with educating all restaurant employees about personal hygiene and cross contamination issues. We also encourage all our members to ask their produce distributors what food safety, audit, and incident management programs they have in place with the growers. Our goal is for all our members to be able to serve leafy greens with confidence.”

Take-Home Message

There are several key take-home messages from the current research, says Christine Bruhn, PhD, director of the Center for Consumer Research at the University of California, Davis, who served on the expert panel.

“Pre-washed salad is probably safer than greens that have not gone through a washing process,” Dr. Bruhn says. “The pre-washing process is so thorough and controlled that if bacteria are where they can be reached by water, they will be washed off. The greens are as clean as anyone can make them due to the process.”

There’s more risk associated with washing pre-washed leafy greens at home or in food service venues than there is with just opening the bag and dispensing them directly onto plates or bowls, says panel member Larry Beuchat, PhD, distinguished research professor with the Center for Food Safety at the University of Georgia in Athens.

“Handling bagged salads provides many opportunities for cross contamination in the kitchen,” Dr. Beuchat adds. “For example, the colander or the water or the hands of the person doing the washing could be contaminated with pathogenic bacteria.”

The second take-home message from current research, Dr. Bruhn says, is that the washing process is not perfect. There can be bacteria in the stem end of the leaves and on the cut surfaces, so washing is not the most foolproof safety step in and of itself. Moreover, in a vat, bacteria can be washed off one leaf and onto another. “The world has bacteria,” Dr. Bruhn says. “Those bugs are going to get into the leafy greens, and sometimes the bacteria are where they can’t be reached. If you want the safest possible product, you need a kill step.”

But a commercially viable kill step is years away, Dr. Gombas says. Irradiation of leafy greens is promising, but it will take time for the FDA to approve a suitable protocol. The FDA has a petition under review to permit the irradiation of multi-ingredient foods, including prepackaged (bagged) fresh produce, for the purpose of controlling microbial contamination. This petition, if approved, would permit the irradiation of prepackaged fresh spinach at specified doses. “But we can’t wait for all that,” Dr. Gombas emphasizes. “It’s critical that research proceeds now in search of a meaningful intervention.”

The third take-home message Dr. Bruhn offers is the importance of proper refrigeration. “Research has demonstrated that E. coli O157:H7 will grow under refrigeration temperatures as low as 50°F,” she says. “Just two or three E. coli cells, multiplying in transportation and storage, can make a susceptible person sick. As few as 10 cells can send them to the hospital. So the retail and food service sectors and their transportation partners need to be extremely careful to maintain proper temperatures during transport and storage, 41°F or less, according to the U.S. Food Code. And consumers need to be mindful of temperature issues once they leave the grocery store with purchased greens.”