@ossobuco,
"When food is cooked and left out for more than 2 hours at room temperature, bacteria can multiply quickly. Most bacteria grow undetected because they don’t produce a bad odor or change the color or texture of the food. Freezing food slows or stops bacteria’s growth but does not destroy the bacteria. The microbes can become reactivated when the food is thawed. Refrigeration also can slow the growth of some bacteria. Thorough cooking is needed to destroy the bacteria."
Bacteria Growth
Bacteria simply multiply by splitting in half. Under the ideal conditions, they can double in number every 15 to 30 minutes. This means that one single bacterium could multiply to a million in less than 6 hours.
What do bacteria need to multiply?
Food " Some from of food is a basic requirement for bacteria to grow.
Moisture " Water is required for bacteria in order to absorb food. Dry foods will not support bacterial growth. As well, foods with very high salt or sugar content make bacteria unable to use the moisture present.
Temperature " Bacteria grow best at warm temperatures between 40 and 140°F. This temperature range is what we call the food danger zone.
Air " Most bacteria require oxygen to grow, but not all. There are some exceptions, one type of bacteria being botulism.
Time " When bacteria are introduced to a new environment, they need time to adjust before they start to grow. This time is called the lag phase and last about one hour.
How is bacteria transferred?
Bacteria are carried from one place to another by being carried. This can happened by peoples hands, coughs, other food, utensils, equipment, water, or pests.
Preventing Bacteria Growth
Now that we know how bacteria grow and are spread; we should be able to prevent food-borne illness by following three simple steps.
1. Keep bacteria from spreading by not letting anything that might contain bacteria tough the food. This includes people, dirty equipment, utensils and possibly other foods.
2. Stop bacteria from growing by taking away the conditions that encourage growth. The most effective way is to keep food out of the danger zone. Keep foods below 40°F and about 140°F
3. Finally kill the bacteria. Most bacteria are killed if they are subject to a temperature above 165°F for 30 seconds. This is how we make food safe by cooking. This heat is also how we sanitize dishes and equipment. Certain chemicals (such as bleach) also kill bacteria. Using sanitizing agents is best way to sanitize counter tops and large equipment.
(That was from another site)
And this one deals with putting hot foods into the fridge - I'd forgotten that in the restaurant we usually chilled the pails of soups, etc in sinks full of ice for quite a while.
http://www.ochef.com/648.htm
And here's another one:
Don't be afraid to put hot foods in the refrigerator. The appliance is made to cool down foods. The chilling process will happen more quickly in the fridge, once again giving bacteria less time to grow in the temperature danger zone of 40 - 140 degrees Fahrenheit. If you have a large casserole or dish that needs to be chilled, separate the foods into smaller, shallow (no more than 3" deep), individual containers for faster cooling.
It can take a pot full of hot chicken soup 24 hours to cool to a safe temperature in the refrigerator! Divide and conquer bacteria!
Don't overload the refrigerator. There should be enough space between foods that air can freely circulate around them. This way the temperature will be more even throughout the appliance.
Foods that need refrigeration should be placed in the refrigerator within 2 hours after eating to help prevent bacteria growth. If the ambient temperature is more than 80 degrees Fahrenheit, that time safety zone shrinks to 1 hour. Don't violate this rule!!!