Non-Thermal Preservation Processes
Non-Thermal Preservation Processes
Food Process |
Purpose |
Food Use Examples |
Used at Home |
Benefits |
Drawbacks |
High Pressure Processing |
A process where a food product in a sealed container is subjected to high iso-static pressure, usually via water |
Fruit and vegetable juice, sauces, dips, dressings, hummus, and deli meats |
No |
Food safety; enables taste closer to freshly made |
High cost associated with equipment and packaging; usually requires refrigerated distribution; limited product application due to high moisture requirement of the food product |
Aseptic Filling |
Filling and sealing a food or beverage product in a sterile environment after the product has been sterilized, usually using Ultra-High Heat Treatment |
Dairy beverage products, juices, fruits, vegetables, soups, and RTE meals shipped & sold at room temperature |
No |
Allows perishable products to be packaged, shipped, sold, and stored at room temperature; could improve flavor; reduces loss of vitamin(s) due to a shorter heat treatment |
Very complex and expensive technology to install and operate; requires specialized expertise to ensure food safety requirements are met |
Membrane Filtration (microfiltration) |
A liquid product is passed through multiple membranes with controlled porosity to remove large pathogenic or spoilage microorganisms that cannot pass through the membranes |
Beverages including juices, milk, wine, water, and beer |
No |
Food safety; avoids or minimizes use of heat treatment to extend product shelf-life; less burnt flavor |
Requires significant redundancy in filtration system to ensure product safety; expensive technology, applicable to liquid products only with particles smaller than the microorganisms |
Acidification |
Organic and/or inorganic acid(s) is added to a food product to increase acidity/reduce the pH below a threshold to prevent growth of pathogenic and spoilage causing microorganisms |
Beverages (e.g., fruit and vegetable juice, soda, sports & energy drinks), salad dressings, mayonnaise, salsa, canned fruits and vegetables, dips, and some types of soft cheese |
Yes |
Food safety; requires only low-moderate heat treatment; reduces cooked or burnt taste; and maintains food structure (e.g., salsa) |
Impacts taste and appearance of the food product; high acid content may not be tolerated by some people |
Fermentation |
A process where non-harmful, live microorganisms (e.g., lactic acid bacteria) use sugars in the food product and generate organic acids which increases acidity/reduces pH below a threshold to prevent growth of pathogenic microorganisms |
Dairy products (e.g., cheese, kefir, buttermilk, yogurt, and sour cream), sausages (e.g., salami), sauerkraut, pickled vegetables, tofu, kombucha, soy sauce, wine, vinegar, and beer |
Yes |
Food safety; shelf-life; requires less heat treatment |
Changes protein structure; could impact taste, texture, and appearance; high acid content may not be tolerated by some people |
Refrigeration |
Growth of spoilage and pathogenic microorganisms is prevented or reduced by decreasing the temperature of the food product and then storing the product at a lower temperature for future use |
Meat, cheese, butter & spreads, yogurt, sour cream, dips, sauces, dressings, milk, juice, eggs, fruits and vegetables, salad mixes, and prepared meals (ready to eat) |
Yes |
Food safety; shelf-life; prevents degradation of some vitamins; preserves flavor and texture of the food product |
Causes thickening of some liquid or soft products; some spoilage microorganism can still grow, although slowly, thereby limiting the shelf-life |
Brining/Marinating
|
Salt and/or sugar is added to a food with high water content (e.g., meat, fruit and vegetables) |
Meat, seafood, fruits and vegetables, feta cheese, jams and jellies, and pie fillings |
Yes |
Food safety; shelf-life |
Significantly changes taste and texture of the food product; increases sodium and/or sugar content of the food product |
Freezing |
Food temperature is lowered to below freezing. Subsequent storage at or below freezing temperature prevents spoilage by slowing or stopping microbial growth |
Frozen meat, vegetables, fruits and fruit concentrates, sauces, prepared meals (e.g., pizza), desserts (cakes & ice cream), frozen potatoes, bagels, and breads |
Yes |
Food safety; shelf-life; preserves vitamins; maintains much of the original taste |
Generally, will not destroy micro-organisms in the food. Changes food texture and sometimes taste. |
Modified Atmosphere Packaging/Storage |
Food product is packaged in a sealed container with minimal or no oxygen, via flushing with an inert gas (e.g., nitrogen), followed by another preservation method such as refrigeration for some food products, to inhibit growth of microorganisms. |
Salad mixes, fresh dips and spreads, meat, cheese and dairy products, fresh fruits and vegetables, and some breads |
No |
Shelf-life; reduces deterioration of flavor, color, and vitamins caused due to exposure to oxygen |
Does not inhibit growth of some pathogenic and spoilage causing microorganisms that require minimal or no oxygen; requires additional preservation method to ensure food safety |
Irradiation |
Application of high energy (Gamma rays, X-rays, electron beams) particles or waves to a food product |
Spices, meat, nuts, fruits and vegetables, wheat and wheat flour, salad mixes, potatoes, and food packaging |
No |
Food safety; inhibits sprouting |
Potential loss of vitamin(s); could impact the color of some food products |