how long does mayo last after opening Hello. Welcome to solsarin. This post is about “how long does mayo last after opening“. Mayonnaise Mayonnaise, colloquially referred to as “mayo”, is a thick, creamy sauce or dressing commonly used on sandwiches, hamburgers, composed salads, and French fries. It also forms the base for various other sauces, such as tartar sauce, fry sauce, remoulade, salsa golf, and rouille. Mayonnaise is an emulsion of oil, egg yolk, …