Meat & Poultry
Red Meat naturally changes colour when it gets exposed to oxygen, particularly minced meat which generally has a larger surface area. The colour of uncooked meat can range anywhere from cherry red to a more brownish hue on the outside, and its interior from a grey-brown to a purplish colour. As such, it can change colour according to how long it has been stored for but this doesn’t mean that the meat has spoiled. Check if the meat has a sticky or slimy surface or gives off a sour odour, as these signs indicate that it has already gone past its edible stage.
The same applies for poultry, if it has a sticky or slimy surface and has a sour odour, it has spoiled. Fresh, uncooked poultry should be a pinkish colour, if it appears to be greyish in colour, it shouldn’t be consumed.
Fish & Shellfish
Fish should appear shiny and firm with moist flesh. For whole fish, bulging eyes and reddish gills indicate a fresh catch. Check the freshness of the fish by applying pressure to it. The flesh should be firm and should not cave in or become mush when pressure is applied. It should also smell clean and mild. If its odour has hints of ammonia or it smells overly fishy, the fish has begun to spoil.
Shellfish such as prawns and scallops can generally be identified in the same way as fish; check for slimy surfaces and an overly fishy odour. Fresh Scallops for example should be slightly pink and have a sweet smell. Cooked seafood should not have any yellowish or greenish discolouration.
Potatoes possess and outer skin which helps to prevent them from oxidising early. The exposed, browning part is usually harmless and the oxidation process can be slowed down by refrigeration.
When potatoes start to turn green, it may be time to throw them out. The green colour is caused by an increase in alkaloid levels when the potato is exposed to the light. A small tinge of green is generally harmless but when the potato becomes increasingly green and starts to taste bitter, it should no longer be consumed.
Fruits & Vegetables
In general, bruising, wilting, the discolouration of leafy greens and the scarring of fruits are usually fine as the aging process starts from the moment the plants are harvested. Remedy the scarred and bruised parts by simply removing these damages portions of the fruit or vegetable.
Fruits and vegetables are prone to soft rot as a result of bacteria invading their tissues. The fruit or vegetable should be carefully examined and the rotted parts should be removed before cooking or eating. Fruits should also be closely inspected for moulds and yeasts, which are toxic to the body. It is better to be cautious and discard fruits which are growing mould rather than risk eating them.
Dairy & Eggs
The natural expiry date of pasteurised milk can be checked be smell. If the milk smells sour, it has begun to spoil. If the milk has started to curdle and become lumpy, it is definitely time to throw it out.
When refrigerated properly, cheese has a long shelf life and many cheeses taste better as they age. However, it is advisable to check cheese that may have been open for a long period of time for mould before consuming.