Unless you are in the food and beverage industry, food safety is not usually something that is foremost in your mind. After all, if something edible has gone off, you can see, taste or smell it, right?
Unfortunately, this is not always true of food that has become contaminated with harmful bacteria.
Mr Edmund Toh, culinary director at hospitality school Shatec, said: "Cooked leftover food becomes susceptible to bacteria growth at a temperature of between 5 and 60 deg C, if left in the open for more than four hours."
Given that the average temperature in Singapore is around 31 deg C, bacteria may already be growing on the food even if it does not look, smell or taste bad, he added.
"There are harmful bacteria that do not affect the look, smell and taste of food. Leftovers should be discarded after four hours," he advised.
Unsafe food can contain harmful bacteria, viruses, parasites or chemical substances, and cause more than 200 diseases - ranging from diarrhoea to cancer, said the World Health Organisation, which dedicated its annual World Health Day on April 7 to the issue of food safety.
Given Singapore's warm climate, it is important to make use of refrigeration to store food safely as microorganisms which cause food spoilage and foodborne illness multiply very rapidly at room temperature. Bacteria can grow in perishable food within two hours.
Cold temperatures slow the growth of these harmful bacteria.
Here, we explore some myths surrounding the safety of food storage.
IN THE FRIDGE
Refrigerate perishable food within two hours of cooking or purchasing it. Try not to put very hot food straight into the fridge.
Many people think this is because it would damage the fridge, said Mr Rishi Ram, senior chef instructor from At-Sunrice GlobalChef Academy.
"It's not the fridge they should worry about; the hot food will raise the surrounding temperature and may end up spoiling the other chilled food in your fridge," he said.
"The recommended practice is to cool food down to room temperature before storing it in the fridge."
But take care not to leave it at room temperature for too long.
Mr Toh said: "Allowing the food to cool down completely before storing it may put the food in the danger zone of providing a conducive environment for bacteria growth."
If you do not have time to wait for hot food to cool down before refrigerating it, divide it into smaller portions before popping these into the fridge.
IN THE FREEZER
Freezing keeps food from spoiling till you cook it, but it does not destroy harmful bacteria.
This means you should not be refreezing food that has been thawed at room temperature as the food may actually contain even more bacteria than it did before.
According to the United States Department of Agriculture, you should not refreeze any foods left outside the refrigerator for more than an hour in temperatures of above 32 deg C.
But food that is thawed in the refrigerator can be refrozen, although there may be a loss of quality due to the moisture lost through thawing, it said. Keep this in mind when purchasing frozen food at the supermarket.
"If you intend to buy frozen meat for storage in the freezer, try not to travel too far away from home to buy it," said Mr Ram.
"Minimise your travelling time and pop the food into the freezer the moment you return home. It should still be frozen."
If you get delayed and the meat has started to thaw, you should not refreeze it, he said.
"It is best to cook it immediately or keep it in the fridge to be used within the next three days."
And if you want to freeze freshly purchased meat or fish, do check whether it has been frozen.
"Very often, even meat from the wet market has been frozen and thawed. If that is the case, you should not refreeze it," said Mr Ram.
If you do not intend to cook it immediately, you can store it in the fridge for another two or three days.
"The fish from the wet market, however, is usually fresh and hasn't been frozen before," he said.
"In some cases, chicken or pork sellers may claim their meat comes fresh directly from a farm. If you are very sure that the meat or fish is fresh and has only been chilled before, you can safely store it in the freezer."
IN THE OPEN
Dried and preserved food should be kept at room temperature, instead of in the fridge or freezer.
This is true until a sealed package has been opened. "Once a pre-packed dried and preserved food is opened, transfer the unused portion into air-tight containers and keep them in the refrigerator to maintain their quality," said the Agri-Food & Veterinary Authority of Singapore, which is responsible for ensuring food-safety standards here.
When storing unopened packages, remember to keep them in a cool and dry place, away from heat or direct sunlight.
If you have cooked more than enough rice for the family, do not store the extra portions in the cooker overnight as it may not keep well. Harmful bacteria can grow on it.
Cooked rice should not be stored in the cooker for more than four hours after it is cooked, said Mr Ram.
"Transfer the rice into another bowl and let it cool to room temperature within two hours before putting it into the fridge."
In the next Healthy Spaces column, we will look at food-safety tips.