Food Safety Facts: Mayonnaise and Dressings

Commercially prepared mayonnaise, salad dressings and sauces are “very safe” and “have a remarkable food safety record.”¹ However, despite a large body of evidence to the contrary, there persists a belief among many American consumers that mayonnaise, in particular, is a major cause of foodborne illness.  For more than 60 years, members of the scientific and regulatory communities have conducted research and published articles that document the safety of commercially prepared mayonnaise and salad dressing.  Time and time again, the popular condiment has been exonerated by leading authorities on food safety.  Yet, the American public refuses to give up the myth about mayonnaise and foodborne illness.

Indeed, commercial mayonnaise and spoonable (mayonnaise-like) salad dressings are carefully formulated with highly acidic ingredients and pasteurized eggs and manufactured under rigorous quality control procedures making these products extremely unlikely sources for bacteria that cause foodborne illness.  These commercial products contain pasteurized eggs that are free of Salmonella and other dangerous bacteria.  Acidulents, such as vinegar and lemon juice, create a high-acid environment that slows, or prevents, bacterial growth.  Salt is also an important ingredient in commercial mayonnaise that contributes to the unfavorable environment for microbial growth.   

Where did the “mayo myth” begin? 
Homemade mayonnaise recipes gave birth to the myth that mayonnaise causes foodborne illness.  Homemade mayonnaise recipes almost always call for raw eggs.  But, scientists now know that uncooked shell eggs can sometimes be contaminated by Salmonella bacteria.  Also, homemade mayonnaise, unlike commercial products, may not contain enough salt and vinegar to counteract the growth of harmful bacteria, as the vinegar and salt levels often vary greatly in recipes for homemade mayonnaise.  

Now, it is unsafe food handling and preparation in home kitchens and foodservice operations that pose a greater threat of bacterial contamination of food.  

Many low-acid foods, like chicken, ham or potatoes, are susceptible to the growth of bacteria and are often mixed with mayonnaise.  Mishandled, these foods can create a favorable medium for food contamination.  There are many potential sources of  bacterial contamination in the on-site preparation of “homemade” recipes, including the various ingredients of these recipes and other foods and surfaces in the kitchen that could serve to cross-contaminate.  It is for this reason that the use of commercially prepared mayonnaise and dressing is encouraged for restaurant and home use.  Despite the microbiological safety of commercial mayonnaise, mixing mayonnaise with contaminated ingredients will not assure the safety of these combined mixtures.

Association for Dressings & Sauces (ADS) Reaffirms Safety of Dressing and Sauce Products
Virulent strains of food bacteria, such as E. coli O157:H7, threaten the world food supply confounding health officials and the food industry.  Outbreaks of E. coli over the last several years implicated a number of foods, including mayonnaise and salad dressing.  In its commitment to continue manufacturing safe, wholesome products, the mayonnaise and dressing industry, through The Association for Dressings and Sauces, continually sponsors and publishes research, which verifies the safety of commercial dressing and sauce products, including mayonnaise. 

One such study sponsored by ADS revealed that E. coli O157: H7 dies off rapidly in commercial mayonnaise at room temperature.² However, any foods contaminated through contact with infected raw beef, utensils or food handlers are susceptible.  There is no substitute for safe food handling by the consumer and those responsible for preparing and serving food to the consumer.  Good sanitation practices will greatly minimize the possibility of cross-contaminating all foods with E. coli and other foodborne bacteria.

The Association for Dressings and Sauces is an international association of manufacturers of dressings for salads, mayonnaise, mustard and specialty sauces and their suppliers.

¹Smittle, R.B.  2000.  Microbiological Safety of Mayonnaise, Salad Dressings, and Sauces Produced in the United States:  A Review.  Journal of Food Protection, Vol. 63, No. 8, pgs. 1144-1153.

²Hathcox, A.K., L.R. Beuchat, and M.P. Doyle. 1995.  Death of enterohemorrhagic Escherichia coli O157:H7 in real mayonnaise and reduced-calorie mayonnaise dressing as influenced by initial population and storage temperature.  Applied and Environmental Microbiology.  61:4172-4177.