During ServSafe MN training there are many times we discuss stories of food poisoning incidents blamed on tainted mayonnaise in potato salad, on sandwiches or in dips. There seems to be strong belief that mayo is highly volatile and extra precautions need to be taken if it is used in food production. If you investigate further, you’ll find that it’s not that mayonnaise that has caused a food borne illness, but other ingredients that have not been prepared to ServSafe MN standards.
ServSafe MN Training and the Mayonnaise Myth
Commercially produced mayonnaise is loaded with acids and preservatives and will generally not spoil even if it’s not refrigerated. Refrigeration of mayonnaise is generally recommended, but it’s more necessary because of diner’s taste preferences, not that it creates a food-safety hazard if it is kept at room temperature. There are even some unverified claims that adding mayo to dressings, dips and cold sauces can extend the life of those products due to the acids and preservatives in commercially produced mayonnaise.
Just to be clear, we are discussing commercially processed mayo. If you make your own mayonnaise in your restaurant, chances are you will be using raw eggs and will not be adding as much acid and preservatives as your standard store bought mayo. If you make your mayonnaise in house, we strongly recommend that you treat it as a volatile food product and keep it under refrigeration at all times.
If it’s not the mayonnaise that causes food-poisoning, then why do common dishes that contain mayonnaise make people ill? Ingredients such as cooked potato, pasta and vegetables are not shelf-stable items. Cooked potato dishes are in fact highly susceptible to bacteria growth. Leaving a potato or pasta salad at room temperature for an extended period of time will create a health hazard for anyone that consumes it. Many potato salads also contain cooked eggs, and eggs are also incredibly susceptible to bacteria if not refrigerated properly.
We have also heard mayonnaise blamed for food poisoning incidents that have occurred as a result of eating at a buffet style event. These illnesses can essentially be tracked to cross contamination that occurs during the course of preparation or service. If a utensil is dipped into another dish on the buffet, or the mayo spreader comes into contact with meat proteins and then is returned to the mayonnaise dish, it is likely the mayonnaise has been contaminated by some sort of bacteria. While that mayonnaise itself may not need refrigeration, any bacteria that have been introduced into it will grow at room temperatures.
No matter how you use mayonnaise in your establishment, ServSafe MN training recommends you should take care to avoid cross contamination and be diligent that every ingredient in your recipe is handled properly.