Is it safe to use mayonnaise in the summer?

Is it a myth that we should avoid using mayonnaise on sandwiches and in salads when they are not refrigerated and during hot months when we go on picnics and hiking?

Last July, the New York Times reported that the acidic ingredients, such as lemon and vinegar, contained in commercial mayonnaise may “actually protect against spoilage.” The August 2000 issue of Journal of Food Protection reported that lactic and citric acids served as natural preservatives by warding off bacteria.

The important safety factor for Europeans

The catch here is that these articles refer specifically to American-made commercial mayonnaises, which use pasteurized eggs and more acids than European ones. And let’s not even discuss homemade ones, for which we cannot control the safety of ingredients used, because they can vary so much.

In Switzerland and France, there is not a wealth of literature available on this subject. However, since most people prefer homemade mayonnaise to the supermarket variety, it is probably advisable to continue to avoid using mayonnaise in summer unless it is kept cool at all times. Better safe than sorry, unless you are a scientist capable of analyzing the acidity and testing that all ingredients are equivalent to those used in the U.S., or of determining the level of bacteria contained in the mayonnaise or mayonnaise-based dish before you eat it.