Etiket Arşivleri: Freezing Food

The Basics of Freezers and Freezing Food

The Basics of Freezers and Freezing Food

IS A FREEZER A LUXURY – Freezing versus Canning


• Easy and fast

• Holds color, flavor and nutrients

• Suited to more foods than canning

• Safe and convenient

• Cost of freezer is an initial high cost, plus electricity to run
• Cost of materials for freezing food can be low especially plastic zip-loc are used versus rigid containers

• No additives required

• Freeze leftovers, extra baked goods, casseroles

• Take advantage of meat and vegetable specials and bulk buying, resulting in considerable cost saving

• Wild game storage (eg. ducks, geese, deer, caribou, moose, elk) are hunted in the fall. Freezing of this ensures a food supply for the rest of the year. Same goes for wild berries


• More technical knowledge

• Takes time

• Discoloration, alteration in flavor and nutrients can be lost if canning liquids not utilized in soups and or gravy

• Manitobans like our dill pickles and canned tomatoes, jellies and relishes

• Can be unsafe if proper processing/canning procedures aren’t followed

• Cost of initial canning equipment is costly, especially pressure cooker, but last a long time
• Jars and lids have to be replaced

• Canned goods require salt and/or sugar, vinegar which is especially important to avoid for individuals on special diets

• Not possible with canning

• Limited to mainly vegetables

• Meat would have to be pressure cooked and therefore is not usually recommended

Freezers can be very cost-saving as it allows bulk and special sales buying. Ensures storage of extra food to
maintain food source during storm days. Canned goods are costly to ship as you are paying for tin and liquid the product is stored in. Frozen products are usually just in light weight plastic type bags or containers. Store bought or home preserved frozen or canned produce are preserved using prime quality produce. A problem with buying fresh produce especially in northern communities is that the quality has deteriorated with long distance shipping. Just a few days in transit causes “fresh” produce to lose significant amounts of all important nutrients. What this means, is that frozen vegetables can be superior (especially in winter) to many of the fresh produce we buy as well as a great cost saving. Good comparisons are broccoli, cauliflower, green beans and strawberries.

Freezing Food

Freezing Food
The frozen food industry was born in the 1920’s
Clarence Birdseye produced the first frozen fish
The industry continued to grow and develop with the growth of such technology as fast-freezing equipment, home freezers, and the microwave oven
The 1950’s brought on the TV dinner revolution
The Science of Freezing
Foods that are free of microorganisms when frozen will remain so, since most microorganisms can’t grow at such a low temperature
Freezer Burn
Caused by the loss of moisture from food when the food is exposed to air
Culprit: Loose packaging, fluctuation in freezer temperature
If not packaged properly, even foods that do freeze well can experience a damaging effect
Foods that are freezer burnt often have a brown or grayish color, look very dry, and have a fuzzy gray or white spots that look like icy mold
Commercial Freezing
Rapid Freezing Process – Limited changes in color, texture, size and flavor
Also, helps foods resist freezer burn
Ice crystals are smaller causing less damage to food cells
Commercial Freezing
Immersion freezing food is submerged directly in non-toxic refrigerant to cause quick freezing
Most packaging is opaque because many foods lose flavor when exposed to light
Home Freezing
Storage containers and wraps used for frozen foods at home must be moisture proof and airtight to maintain quality
Even if it is properly maintained it has a 6-12 month period before it starts to deteriorate
Foods with high water content, including grapes, pears, salad greens, lose shape and texture when frozen
Be sure to label and date all packages!!
Is a commercial process that combines freezing and drying to preserve foods.
First food is frozen; then its treated to remove the solvent from dispersed or dissolved solids.
In most food, this means removing the water.
Technical name: lyophilisation.
During freeze-drying, water in the form of ice is removed through sublimation – occurs on the surface and continues inward.
Wet clothes on the line during winter example.
By the time the ice at the very center has sublimed, up to 99% of the food’s moisture has been removed.
The result is dried food.
Flash frozen or frozen very quickly – a special, low-pressure chamber. It is then held at or below freezing temperature.
The low temperature keeps the water frozen, and the low pressure speeds the rate at which ice crystals in the food escapes as water vapor.
Using Freeze Dried Foods
Foods could be stored for months even years
Must be protected in airtight packaging
Examples are fruit in cereal and chicken in instant soup
Makes foods extremely light – should be reconstituted.

Packaging Food
Suitable containers
Safety – needs to be non-toxic and provide a sanitary, protected environment
Food quality – must provide protection from light, odors
Convenience – open easily, resealable, and able to pour easily are a +
Expense – lower packaging means lower cost for manufacturers and the result is a lower cost to consumers!
Environmentally safe – recyclable containers!
Marketing appeal – attractive to the consumer!
Packaging Food
Modified-atmosphere packaging
Called MAP – This process creates a specific gaseous environment for a food product to lengthen shelf life.
Used mainly for ready-to-eat products with extended shelf lives.
Bags of lettuce, baby spinach, and baby carrots use this technology in stores!
Packaging Food
Aseptic packaging
Used for beverages and liquids that have been aseptically treated – extremely high temperatures and contain several layers of material.
Containers are not recyclable.
Example: Drink boxes!
Packaging Food
Edible films/wraps
Additional film added to apples – Wax
Trends in packaging
Edible films
“Smart” packaging that tells the consumer a number of things – if the temperature has ever risen enough above the proper temperature the the contents of the package may be unsafe to consume
“Intelligent” packaging that tells the consumer whether or not the contents are spoiled and may not be safe to eat. Ex. A dot that may change colors
One third of the world’s food supply is still degraded or destroyed by pests, bacteria, and the resulting spoilage.
Irradiation – food is exposed to a controlled amount of radiation (transfer of energy in the form of waves) for a specific time to destroy organisms that would cause spoilage.
Radura Symbol – Page 462
The FDA (Food and Drug Administration) regulates irradiation as an additive.
Delaney Clause – states that no substance shown to cause cancer in humans or animals may be added to food in any amount.
The FDA approves food for irradiation on a case-by-case basis.