|
Types of Bacteria in Refrigerated Foods There are two completely different families of bacteria: pathogenic bacteria, the kind that cause foodborne illness, and spoilage bacteria, the kind of bacteria that cause foods to deteriorate and develop unpleasant odors, tastes, and textures.
Pathogenic bacteria can grow rapidly in the "Danger Zone," the temperature range between 40 and 140 °F, but they do not generally affect the taste, smell, or appearance of a food. In other words, one cannot tell that a pathogen is present.
On the other hand, spoilage bacteria can grow at low temperatures, such as in the refrigerator. Eventually they cause food to develop off or bad tastes and smells. Most people would not choose to eat spoiled food, but if they did, they probably would not get sick. It comes down to an issue of quality versus safety:
* Food that has been left too long on the counter may be dangerous to eat, but could look fine. * Food that has been stored too long in the refrigerator or freezer may be of lessened quality, but most likely would not make anyone sick. (However, some bacteria such as Listeria monocytogenes thrive at cold temperatures, and if present, will multiply in the refrigerator and could cause illness.)
RAW ROASTS, STEAKS, CHOPS, SMOKED REFRIGERATE IMMEDIATELY IN RETAIL PACKAGES OR WRAP LOOSELY IN FRESH WAXED PAPER OR ALUMINUM FOIL TO ALLOW FOR AIR CIRCULATION. STORE IN COLDEST PART OF REFRIGERATOR. ROASTS: 2-5 DAYS STEAKS: 2-5 DAYS CHOPS: 3-4 DAYS STEW MEAT: 1-2 DAYS SMOKED HAM: 1 WEEK** FRESH PORK: 3 DAYS
FOR FREEZING, WRAP IN ALUMINUM FOIL OR FREEZER PAPER.** BEEF & LAMB: 6-9 MONTHS. FRESH PORK: 2 MONTHS. VEAL: 3-4 MONTHS. SMOKED HAMS: 1-2 MONTHS.**
(personally I don't like to use foil - freezer paper is best.)
Meat Spoilage
Meat is considered to be spoiled when it is unfit for human consumption. A variety of factors can cause meat to spoil including micro-organisms, exposure to air, and improper freezing techniques. Spoiled meat may be inedible due to unpleasant tastes and odors or may be unsafe for consumption especially when micro-organisms have caused the meat to spoil.
Meat Spoilage by Bacteria, Yeasts, and Molds
Although a number of factors may contribute to meat spoilage, the most common cause of meat spoilage is the deterioration of meat caused by micro-organisms (bacteria, yeasts, and molds). Beware! Foods can contain dangerous bacteria and microorganisms but still have a normal appearance. Food which has not been handled or stored properly should not be eaten even if it has no apparent indications of spoilage. See Food-borne Illnesses for more information.
The table below shows some of the common indications that meat has spoiled.
Indication of Spoilage/Cause
Ammonia or sulfur smell, bad odor, tallow or chalky taste. Degradation of proteins, lipids (fats) and carbohydrates caused by bacteria and/or enzymes naturally present in meat. Slime formation, bad odor and rancid flavor, color change (such as grey, brown, or green) Bacterial and yeast spoilage Sticky meat surface Mold spoilage "Whiskers" Mold spoilage Surface colorations such as creamy, black or green Growth of mold colonies Tainting, souring, and putrefacation Anaerobic bacterial spoilage of meat interiors, vacuum packed products, and sealed containers
Other Types of Spoilage
There are factors other than micro-organisms which can cause meat to spoil. They results from improper handling of meat.
Indication of Spoilage/Cause
Oxidative Rancidity (rancid flavor and odor) Oxidation of meat fats due to improperly wrapped meat. Brown or grey discoloration Protein denaturation caused by heat, salts, ultraviolet light, low pH, and surface dehydration Dehydration and discoloration during freezing resulting in dryness of cooked meat, nutrient loss, and sometimes a bitter flavor. Freezer burn and drip which occurs during slow freezing. Absorption of Off-Flavors Storage of meat next to foods such as apples and onions which give off strong odors
|