It depends on the food. Potentially hazardous food (eggs, milk, meat, chicken, fish, etc.) should not be unrefrigerated for more than 2 hours, but less time is better. Butter and margarine and many condiments will be OK for a longer period of time. When in doubt, throw it out.
You can freeze many foods. Some foods can be salted. Canning or putting it into jars can keep many foods fresh. You can also pickle or brine some foods. Some foods keep well if you just seal them into plastic.
all and any foods should not be kept longer than 3 days before canning/jarring.
This food should not be left out. Cooked foods should be cooled quickly for cold storage. It can only take a hour for cooked foods to be contaminated.
the body can be kept for a least 6 days before it starts to rott and the body turns purple and blue.
It depends on where you are. Heres a list of how long different records should be kept. I think this is in the UK
Fish can be kept in the fridge for up to 2-3 days before it goes bad.
30 minutes
Food left out of the refrigerator is okay to eat for about 2 hours. If the temperature is under 80 degrees. The longer a food stays in the danger zone the more risk you take eating that food. Foods should either be kept hot or kept cold before eating to be really safe.
Breastmilk can be safely kept out of the fridge for up to 4 hours before it needs to be discarded.
Precooked foods should generally be kept in the refrigerator for 3 to 4 days. If you need to store them for a longer period, it's best to freeze them, where they can last for 2 to 6 months, depending on the type of food. Always ensure that precooked foods are stored in airtight containers to maintain quality and prevent contamination. Additionally, reheat them to at least 165°F (74°C) before consumption.
MRI films are kept as long as necessary, especially if you see the same doctor. You can have records transferred and then your new doctor will have them. They are consistently kept on record for years before they are not needed.
Most food used at fast food restaurants is frozen, so it is not actually fresh. How long it is frozen before it is used is not known. After food are cooked, there is a hold time for how long it can be kept under the warming lights. Foods like lettuce that cannot be frozen usually contain preservatives to make it look fresher longer, but it is not known for how long.