Non-Thermal Preservation Processes

Processes that make the food safe for consumption and extend the shelf-life of a food using alternative technologies without heat to reduce/eliminate/inactivate microbial contamination in the food.

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 Processing & 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