July 26, 2001

Prairie Fare: And the Verdict Is…

By Julie Garden-Robinson, Food and Nutrition Specialist
NDSU Extension Service

Can you name a food that’s often falsely accused of causing foodborne illness outbreaks? If your first thought was mayonnaise, you’re right.

Even though deli salads and sandwiches containing mayonnaise are linked with outbreaks, mayonnaise is most likely an innocent bystander. It gets its reputation because mayonnaise used to be commonly prepared at home, using raw eggs, which may contain Salmonella.

Commercially, mayonnaise is made in a highly controlled environment. Consisting of oil, eggs, an acid like vinegar or lemon juice and flavorings, commercial mayonnaise products contain up to 82 percent oil. According to legal standards, mayonnaise must contain a minimum of 65 percent oil.

A research study put commercial mayonnaise to the test. The mayonnaise was inoculated with Salmonella and mixed with chicken and ham. Researchers found that mayonnaise, because of its acidity, actually decreased the growth of bacteria. They even kept the mayonnaise-meat mixture at room temperature and saw a decrease in bacterial growth – but don’t try this temperature-defying experiment at home!

The researchers also tried the experiment using reduced-calorie mayonnaise, which contains more water and less oil and vinegar. The lower-calorie version killed fewer bacteria. Some other researchers, however, have shown that certain strains of bacteria can survive the acidic environment of mayonnaise, so the old food safety "laws" still apply.

The semi-protective effect of mayonnaise only goes so far. In salads, the usual culprits leading to foodborne illness issues are contaminated ingredients and temperature abuse.

Foods are not sterile. Always wash your hands and carefully clean fresh produce. When making a salad, start with cold ingredients and refrigerate the finished product immediately. At a picnic on a warm day, for example, perishable foods should spend no more than one hour on the serving table. Allowing mayonnaise-containing salads to stand in warm temperatures can give bacteria the opportunity to grow to levels that could cause foodborne illness. For extra safety, serve the salad in a container over a bed of ice or use an ice-filled cooler to maintain a cold temperature.

To preserve the freshness of mayonnaise, keep it refrigerated. Close the jar quickly after using the product, because moisture, mold spores from the environment and crumbs from foods can lead to spoilage.

Foodborne illness cases carry a high price tag, so prevention is key. Each year in the United States about 76 million people become ill 325,000 are hospitalized and 5,000 die due to foodborne illness according to the Centers for Disease Control and Prevention.

According to the USDA Economic Research Service, between 1989 and 1997 about 42 percent of foodborne illness cases were settled for the plaintiff when the specific bacteria was known. The average court settlement was over $197,000. When the organism wasn’t known, about 22 percent of the cases were decided for the plaintiff, and the award was about $133,000. The top five food items in lawsuits overall were sandwiches, seafood, chicken, hamburgers and oysters. Salmonella was the most common organism named in lawsuits.

Don’t let bacteria spoil your meal. Follow the food safety guidelines. Here’s a colorful main dish salad recipe to try. It has less fat than expected because it includes lower-fat mayonnaise. For extra flavor, try grilling the chicken before dicing and marinating it.

Chicken Salad

Ingredients:
5 skinless chicken breasts, cooked and diced
2 tablespoons vegetable oil
2 tablespoons orange juice
2 tablespoons vinegar
1/2 teaspoon salt
1 1/2 cup light mayonnaise
3 cups cooked macaroni rings
1 1/2 cup seedless green grapes
1 1/2 cup diced celery
1 cup pineapple tidbits, drained
1 cup mandarin orange segments, drained
1 cup cashews (optional)

Procedure:
Combine chicken with oil, orange juice, vinegar and salt. Cover and marinate in refrigerator for several hours or overnight. Just before serving add other ingredients and gently mix. Makes 12 servings. With cashews, each serving contains 380 calories and 20 grams of fat. Without cashews, each serving contains 315 calories and 14.3 grams of fat.

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Source: Julie Garden-Robinson, (701) 231-7187, jgardenr@ndsuext.nodak.edu
Editor: Tom Jirik, (701) 231-9629, tjirik@ndsuext.nodak.edu