Foods in the freezer — are they safe?
The confusion seems to be based on the fact that few people understand how freezing protects food. Here is some information on how to freeze food safely and how long to keep it.
What Can You Freeze?
You can freeze almost any food. Some exceptions are canned food or eggs in shells. However, once the food (such as a ham) is out of the can, you may freeze it.
Being able to freeze food and being pleased with the quality after defrosting are two different things. Some foods simply don't freeze well. Examples are mayonnaise, cream sauce and lettuce. Raw meat and poultry maintain their quality longer than their cooked counterparts because moisture is lost during cooking.
Does Freezing Destroy Bacteria & Parasites?Freezing to 0 °F inactivates any microbes — bacteria, yeasts and molds — present in food. Once thawed, however, these microbes can again become active, multiplying under the right conditions to levels that can lead to foodborne illness. Since they will then grow at about the same rate as microorganisms on fresh food, you must handle thawed items as you would any perishable food.
Trichina and other parasites can be destroyed by sub-zero freezing temperatures. However, very strict government-supervised conditions must be met. Home freezing cannot be relied upon to destroy trichina. Thorough cooking, however, will destroy all parasites.
Freeze food as fast as possible to maintain its quality. Rapid freezing prevents undesirable large ice crystals from forming throughout the product because the molecules don't have time to form into the characteristic six-sided snowflake. Slow freezing creates large, disruptive ice crystals. During thawing, they damage the cells and dissolve emulsions. This causes meat to "drip" and lose juiciness. Emulsions such as mayonnaise or cream will separate and appear curdled.
Ideally, a food 2-inches thick should freeze completely in about 2 hours. If your home freezer has a "quick-freeze" shelf, use it. Never stack packages to be frozen. Instead, spread them out in one layer on various shelves, stacking them only after frozen solid.
So how can bacteria harm you?
Improperly processed or packed meats and other foods can be contaminated with psychotrophic bacteria and moulds. The bacteria may also be present in unhygienic conditions in refrigerators or freezers. So when you eat foods contaminated with such bacteria, they will grow in your body and exhibit pathogenic conditions. Some bacteria may not be harmful themselves but they release toxins into the food which causes food poisoning. Bacteria such as some Coliforms, Pseudomonas sp., Vibrio sp. and Listeria sp. and moulds such as Penicillium and Cladosporium sp. are all known to survive low temperatures and become harmful once they are inside the human body.
And what do you do to protect yourself from food poisoning?
The following practices can safeguard you and your family from food poisoning (see the links below for details):
The confusion seems to be based on the fact that few people understand how freezing protects food. Here is some information on how to freeze food safely and how long to keep it.
What Can You Freeze?
You can freeze almost any food. Some exceptions are canned food or eggs in shells. However, once the food (such as a ham) is out of the can, you may freeze it.
Being able to freeze food and being pleased with the quality after defrosting are two different things. Some foods simply don't freeze well. Examples are mayonnaise, cream sauce and lettuce. Raw meat and poultry maintain their quality longer than their cooked counterparts because moisture is lost during cooking.
Does Freezing Destroy Bacteria & Parasites?Freezing to 0 °F inactivates any microbes — bacteria, yeasts and molds — present in food. Once thawed, however, these microbes can again become active, multiplying under the right conditions to levels that can lead to foodborne illness. Since they will then grow at about the same rate as microorganisms on fresh food, you must handle thawed items as you would any perishable food.
Trichina and other parasites can be destroyed by sub-zero freezing temperatures. However, very strict government-supervised conditions must be met. Home freezing cannot be relied upon to destroy trichina. Thorough cooking, however, will destroy all parasites.
Freeze food as fast as possible to maintain its quality. Rapid freezing prevents undesirable large ice crystals from forming throughout the product because the molecules don't have time to form into the characteristic six-sided snowflake. Slow freezing creates large, disruptive ice crystals. During thawing, they damage the cells and dissolve emulsions. This causes meat to "drip" and lose juiciness. Emulsions such as mayonnaise or cream will separate and appear curdled.
Ideally, a food 2-inches thick should freeze completely in about 2 hours. If your home freezer has a "quick-freeze" shelf, use it. Never stack packages to be frozen. Instead, spread them out in one layer on various shelves, stacking them only after frozen solid.
So how can bacteria harm you?
Improperly processed or packed meats and other foods can be contaminated with psychotrophic bacteria and moulds. The bacteria may also be present in unhygienic conditions in refrigerators or freezers. So when you eat foods contaminated with such bacteria, they will grow in your body and exhibit pathogenic conditions. Some bacteria may not be harmful themselves but they release toxins into the food which causes food poisoning. Bacteria such as some Coliforms, Pseudomonas sp., Vibrio sp. and Listeria sp. and moulds such as Penicillium and Cladosporium sp. are all known to survive low temperatures and become harmful once they are inside the human body.
And what do you do to protect yourself from food poisoning?
The following practices can safeguard you and your family from food poisoning (see the links below for details):
- Keep your refrigerators clean by wipping up spills immediately, cleaning surfaces thoroughly with hot, soapy water and then rinsing.
- throw out perishable and expired foods that should no longer be eaten. A general rule of thumb for refrigerator storage for cooked leftovers is 4 days; raw poultry and ground meats, 1 to 2 days.
- Verify the temperature of the refrigerator. Refrigerators should be set to maintain a temperature of 40 °F or below.
No comments:
Post a Comment