Food preservation
Food preservation uses physical, chemical, or biological methods to slow spoilage and maintain food safety or quality during storage.
Water activity: The amount of water available for microbial growth and chemical reactions in a material. Drying and adding salt or sugar preserve food by lowering available water.
Canning: A method that seals food in containers and heats it to destroy dangerous microorganisms. Low-acid foods require carefully controlled canning to prevent botulism.
Food microbiology: The study of microorganisms associated with food, including their roles in spoilage, fermentation, and disease. Microbial growth is a central target of many preservation methods.
Minimal processing: Food handling that makes limited changes while retaining qualities close to those of fresh food. It favors freshness over the long storage stability achieved by stronger preservation.
Thermal processing: The use of heat to reduce microorganisms or enzymes in food. Heating can destroy hazards and spoilage organisms, with intensity determining shelf stability.
Pickling: Preserving food in an acidic liquid, often vinegar, or through acid-producing fermentation. Acidity makes pickling useful for vegetables and other foods that tolerate sour flavors.
Food spoilage: Undesirable changes that make food unacceptable in flavor, texture, appearance, or safety. Preservation aims to delay these changes, though quality loss and safety risks differ.
Ultra-high-temperature processing: A brief treatment at very high temperature used to make packaged foods commercially sterile. It offers room-temperature stability but can alter flavor more than gentler methods.
Refrigeration: The removal of heat to keep materials at low temperatures. Cold storage slows microbial growth and many reactions that cause food to deteriorate.
Food drying: The removal of moisture from food to reduce its water activity. Dried foods become lighter and less hospitable to many spoilage organisms.