What do "use by" and "best-before" dates really mean?

Should you throw out that unopened packaged cheese because has passed its use-by date? 

Next time you’re about to throw food in the rubbish, you should double check the dates on it first. 

Food safety experts say some labelling is confusing – and you could be throwing out food that is actually still perfectly safe to eat.

Today is World Food Safety Day (who knew?) an annual call for the production and consumption of safe food for the benefit of people, the planet and the economy. 

It aims to draw attention and inspire action to help prevent, detect and manage foodborne risks.

 

Dr Alison Jones, a food technologist from the University of New South Wales School of Chemical Engineering, says that food labelling can be confusing and stresses the fact that use-by and best-before dates are very different.

 

“Food manufacturers are responsible for determining the type of date marked on their products to help give consumers a guide as to how long the food product will last before it deteriorates,” she says.

 

“This is particularly important in determining the quality, nutrition and microbiological safety of food.”

 

A use-by date indicates that the safety of the product cannot be guaranteed after the displayed date. Food should not be eaten after its use-by date, and it is illegal for retailers to sell food after its use-by date for health and safety reasons (something many supermarkets ignore).

Foods which display use-by dates are commonly those where the health and safety of the food cannot be guaranteed after a certain date, and often where the spoilage is not clearly discernible before consumption, for example, fresh pasteurised milk, chilled ready-to-eat foods or deli meats. 

Best-before dates indicate that the product may suffer some loss in quality after the displayed date - but may still be safe to eat. That’s provided its packaging is intact and/or it has been properly stored since food can spoil prematurely if it has been subjected to factors including temperature abuse, physical damage, broken packaging, high humidity.

Most foods which display a best-before date should still be safe to eat for a little time after, and retailers can still sell food after the best-before date provided it is still fit for human consumption.

Foods that commonly carry best-before dates are those which do not support the growth of pathogens or, in the case of fresh meat for example, where a later process such as cooking will destroy any bacteria that might be present.

Examples of foods that usually have a best-before date are shelf-stable foods such as retorted canned products and pouches, low-water activity foods such as confectionary, tea, freeze-dried coffee, sugar, salt, cereals and dried fruits. Other examples include acidic fermented products such as yogurt or sauerkraut or frozen products.

If products require special storage conditions in order for the date markings to be effective, then manufacturers can provide specific storage condition statements on the packaging. This is compulsory in the case of a use-by date where specific storage is essential for the health and safety of the product – so it’s important to keep an eye out for these.

So how long is a food still safe to eat after its "best before" date?

That very much depends on the food – the best advice is to look for signs of deterioration, spoilage and/or damage such as mould, slime, rancidity, off-flavours or odours, staling, gas-production or broken packaging.

As a consumer, you should also follow any of the manufacturer’s specific storage instructions to ensure the best-before and use-by dates are effective.