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What Pathogenic Bacteria Need to Grow
Bacteria
will begin to grow and multiply when they are comfortable in their
surroundings. It will double every 20 minutes if its surroundings are
perfect.
Most
bacteria grow where there is oxygen (Aerobic "with oxygen") and some can only grow when
there is no oxygen (Anaerobic
"without oxygen").
Bacteria need a combination of things in their surroundings to grow:
- Temperature - Bacteria grow best in
the temperature range between 4ºC and 60ºC. Temperature below
4ºC, and temperature between 60ºC and 74ºC, will not
kill bacteria, but it will not allow them to multiply enough times to
cause an illness. In order to kill pathogenic bacteria you need
temperatures above 74ºC. Temperature is the easiest factor to
control in order to prevent bacterial growth.
- Protein - Pathogenic bacteria and spoilage
bacteria grow best in high protein food such as poultry and seafood.
- Water - Pathogenic bacteria need water in order to
survive. Food can be changed in order to reduce the amount of water.
Food can also be salted, dried, smoked, have sugar or pectin added.
Lower water will not kill bacteria, but it will not allow them to grow.
- pH (the measure of the level of acid)
- Pathogenic bacteria need a neutral
environment to survive. The level of acid can range from 0 to 14. Tap
water has a pH of 7 (neutral), vinegar has a pH factor of 3 (acidic),
bleach has a pH factor of 13 (alkaline). Low or high pH factor will not
kill
pathogenic bacteria, but it will not allow them to grow.
Most disease causing bacteria grow best at pH of 5 to 8.
- Oxygen - Some pathogenic
bacteria can only grow where there is oxygen, while other pathogenic
bacteria can only grow where there is no oxygen. You should be aware of
those bacteria that grow without oxygen in canned and jared products
and those that need oxygen in other food products.
- Time - Pathogenic bacteria need enough time in
order to multiply. The number of bacteria will reach dangerous levels
very quickly in a short period of time in perfect conditions. Keep in
mind that bacteria can reproduce every 20 minutes in perfect conditions.
By sufficiently eliminating or changing one
of the criteria, bacterial growth can be prevented or delayed.
Related Links:
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What
Consumers
Need to Know |
To
avoid the possibility of foodborne illness, fresh eggs must be
handled carefully. Even eggs with clean, uncracked shells may
occasionally contain bacteria called Salmonella that can
cause an intestinal infection.
Consumers play a large role in this prevention strategy. In
fact, the most effective way to prevent egg-related illness is by
knowing how to buy, store, handle and cook eggs—or foods that contain
them—safely.
Safe Handling Instructions: To
prevent illness from
bacteria: always keep eggs refrigerated, cook eggs until yolks are
firm, and
cook foods containing eggs thoroughly.
Following these instructions is important for everyone but especially
for those most vulnerable to foodborne disease—children, the elderly,
and persons with weakened immune systems due to steroid use, conditions
such as AIDS, cancer or diabetes, or such treatments as chemotherapy
for cancer or immune suppression because of organ transplants.
Eggs that have been treated to destroy Salmonella—by in-shell
pasteurization, for example are not required to carry safe
handling instructions.
Buy Right
- Buy eggs only if sold from a
refrigerator or refrigerated case
- Open the carton and make sure that the eggs are clean and the shells
are not cracked.
- Refrigerate promptly.
- Store eggs in their original carton and use them within 3 weeks for
best quality.
Keep Everything Clean
Before preparing any food, remember
that cleanliness is key! Wash hands,
utensils, equipment, and work surfaces with
hot, soapy water before after they come in contact with eggs and
egg-containing foods
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