Explain how to maintain foods at proper temperature after purchasing it.

Refrigerate foods quickly. Cold temperatures keep most harmful bacteria from growing and multiplying. Bacteria grow most rapidly when food is in the danger zone between 40 and 140 degrees F.

Perishable foods that are kept at unsafe temperatures can support the growth of bacteria. Therefore, do not keep perishable food at room temperature for more than two hours. Do not leave out food for more than one hour if the room or outside temperature is 90 degrees F or hotter. This rule also applies to take-out foods and leftovers from home, a restaurant, or a Meals on Wheels delivery.

Shopping

Buy foods labeled "Keep Refrigerated" only if they are stored in a refrigerated case in the store.
Buy frozen foods only if they are frozen to the touch in the store.
Shop for refrigerated and frozen products last. Pack them together. If it takes more than one hour to get home, use a cooler to transport them home.
Within two hours (or one hour if it is hotter than 90 degrees F outside), refrigerate, freeze, serve, or reheat cooked foods.
When returning from the grocery store, store groceries inside the car and not in the trunk of the car. The trunk of the car, especially during the summer months, can sometimes reach temperatures over 100 degrees F.

Storing

Set your refrigerator between 34 and 38 degrees F to keep food safe. Use a refrigerator thermometer to check the temperature of the refrigerator. The thermometer should be placed in the warmest location of the refrigerator, which is usually towards the front of the unit.
If raw meat, chicken or seafood juices spill in your refrigerator, clean them up with soapy water, then rinse, and sanitize with a solution of one cap of unscented bleach per gallon of warm (not hot) water. The sanitizing solution does not need to be wiped off.
Keep your freezer at 0 degrees F or colder. Defrost your freezer when the ice builds up. Foods do not last indefinitely in a refrigerator or freezer. Use up foods quickly.
Be sure that you have enough refrigerator or freezer space for your foods. Cool air needs to circulate to keep food safe.
Do not store perishable foods in the refrigerator door. Put them on the shelves in the main part of the refrigerator. The temperature of foods stored in the door can increase when the refrigerator is opened.

Emergencies

If a refrigerator or freezer stops working, keep the doors closed. If the refrigerator/freezer will be off for a long time, another cold storage location must be found, such as in a neighbor's home, a school, or a church.
Refrigerated foods -- Foods will stay cold for four to six hours. Open the door only to add bags of ice. When the refrigerator is working again, check the temperature to see if it is still 40 degrees F or colder. Perishable foods which have been kept above 70 degrees F for more than two hours should be thrown out.
Frozen foods -- Foods in a full freezer will stay frozen for about two days. Foods in a half-full freezer will stay frozen for about one day. Cover the freezer with blankets, but be sure to keep the air vent uncovered. When the freezer is working again, check the temperature to see if it is still 0 degrees F or colder. Freeze foods that have ice crystals.