Mayonnaise has often been blamed when people become sick after picnics, potlucks, and family barbecues, but the mayonnaise itself is not always the main concern. Commercially produced mayonnaise is generally formulated with ingredients and processing methods designed to help maintain food safety, including pasteurized eggs in many products and acidity that can limit the growth of certain harmful bacteria.
The greater concern can arise after the jar has been opened, particularly when everyday handling habits introduce other foods or contaminants into it or when the product is left outside refrigeration for too long.
