Store-bought mayonnaise contains pasteurized eggs and acidic ingredients that hinder bacterial growth, but unwashed utensils and open air can easily introduce contamination after opening.
Keeping mayonnaise safely chilled at or below 40°F (4°C) is essential, as perishable foods left out at room temperature for over two hours can become hazardous.
Homemade mayonnaise carries higher risks due to raw egg ingredients, making pasteurized eggs and immediate refrigeration crucial for preventing foodborne illness.
Checking for altered smells or textures, avoiding cross-contamination, and returning jars promptly to the refrigerator ensure your mayonnaise stays safe and enjoyable.