Is it time to chuck out sell-by dates?

Half of us throw food away when the label says, while the rest just sniff it and see. The result is confusion, waste – and a booming new market in out-of-date produce.

We've all been there, hovering indecisively before the open fridge, weighing up whether or not to play the culinary equivalent of Russian roulette with the last bacon rasher from that special-offer multipack that's just passed its "sell by" date. Chances are you'll get away with it – waste not, want not, and all that. But then again, what if you take the risk and only find out it isn't safe to eat when you end up sick?

It's a daily dilemma played out in kitchens nationwide thanks to widespread uncertainty about the different date labels on the packaged foods and drinks we buy – advice that can at best seem confusing, at worst contradictory, and which is fast dividing the country.

On the one hand, many of us are increasingly erring on the side of caution, chucking away considerable volumes of still-usable food.

The Department for the Environment, Food and Rural Affairs says British consumers each year throw out 370,000 tonnes of food that has passed its "best before" date, and a further 220,000 tonnes that is close to, but still within, its "use by" date. On the other hand, growing numbers of us are fuelling a burgeoning online trade in food and drinks that are sold at cut prices because they are too close to their "use by" date for high street shops to have them on their shelves.

Just last week, one such online discounter, Approved Foods, announced that its sales for the final week of December were up a staggering 500 per cent year on year. At sites such as Approved Foods and Bargainfoods.co.uk, you can pick up four tins of pinto beans for £1, or a can of tuna for 59p. Or how about four Toblerones for 99p? There's nothing wrong with the foods. They're just coming up to their "use-by" dates or have gone beyond their "best before" dates.

Food shoppers typically fall into one of two groups: they are either chucker-outers or sniff-and-hopers. Which approach is right is muddied by the combined effects of ignorance and the profusion of on-pack advice – which last year led the Environment Secretary, Hilary Benn, to call on food manufacturers to consign to the dustbin date labels such as "sell by" and "display until", retaining only the crucial "use by" date.

For generations, shoppers have relied on gut instinct to determine foods' usability. Date labelling, however, has made us lazy, it seems.

"British consumers have lost the knack of using their own judgement," believes home economist Marguerite Patten, whose oral history contribution on wartime food is part of an exhibition starting at the Imperial War Museum next month.

"In the old days sometimes we got bugs, and perhaps this made us more resilient, but we were good judges by using our sense of smell and sight."

Fresh meat would always be looked at not once, but twice, for the brightness of its colour, which denotes freshness, she explains. Chicken should be smell-free and certainly not slimy to the touch. Fish was sniffed to check it smelled not fishy but of the sea. Jam, if prepared and stored correctly, could last for years.

" 'Display until' is nothing about usability. They should display something until it is unusable. That is one thing food companies could easily change. The current collection of date labels is needlessly confusing," Patten believes.

Caroline Bloor, head of consumer testing at the Good Housekeeping Institute, shares this concern. "There is widespread confusion, and it is leading to needless waste," she says. "A recent survey of Good Housekeeping readers showed that 34 per cent admitted to throwing out food just because it had passed its "sell by" date. Only 11 per cent claimed to use everything they bought."

Smell, colour and texture alone, however, are not sufficiently reliable indicators of a food's usability. This fact was recognised in the early Nineties, when the EU introduced a food labelling directive requiring all food companies to place a "use by" date on perishable goods to indicate product safety, and a "best before" date on non-perishable items indicating when quality is at its best. (Under the same directive, a "best before" date was required on all eggs which, to all intents and purposes, means "use by".)

Almost two decades on and "use by" and "best before" remain the only date labels that consumers should follow, a Food Standards Agency spokesman insists. The "display until" and "sell by" labellings were developed by the food industry solely for internal use, to help manage stock, the spokesman points out.

The period during which a food item is usable – widely, if somewhat misleadingly, referred to as its "shelf life" – is dictated by a variety of factors, including exposure to light and heat, transmission of gases, mechanical stresses and contamination, Julian Hunt, director of communications at the Food & Drink Federation explains. Food companies base their "use by" dates on detailed analysis of different foods' perishability by in-house scientists.

"The point about 'use by' is that it's about the micro-biological apects of food, which you simply can't tell by opening the packet and smelling its contents," Hunt says. "You can't smell salmonella or listeria, but if you're not careful both can make you very ill."

A recent FSA study revealed a rise in the potentially deadly disease listeriosis due to people consuming chilled ready-to-eat foods – products such as pre-packed sandwiches, salads, cooked sliced meats, smoked salmon, soft cheeses and pates – that have been in their fridges too long. The findings highlight the potential risks involved in both our ignorance and our habits of going on gut instinct.

"Most people are conservative and cautious about the usability of food, and rightly so, because when it comes to food safety no food company is willing to take a risk," Hunt adds. But it is the industry's understandable tendency to err on the side of caution that, others suggest, further blurs the whether-to-chance-it-or-not debate.

Take "freeze on day of purchase". While many fresh products carry this instruction, WRAP, the government-backed Waste & Resources Action Programme, advises that such products can be safely frozen right up to their "use by" date.

"The key to the usability of any product is ensuring you store it according to the manufacturer's advice," WRAP campaigns director Doreen Macintyre explains. "Perishable products labelled 'freeze on day of purchase' can be safely frozen right up to their 'use by' date, so long as they've been stored correctly."

And how about "consume within two days of opening"? In this case, although the experts readily concede that most – if not all – of us do chance it sometimes, with dairy products especially, they are reluctant to endorse this behaviour, just in case. Bloor points out: "If chilled in a fridge properly, you might find an item opened is still usable beyond this time. But you should still be careful because you won't know – nor will you be likely to be able to tell – the extent to which that product has degraded."

Although smoking or curing food traditionally extended its shelf life, current official advice is that such processes mean those foods have been in the manufacturing system longer, which, in turn, will bring forward their "use by" date.

This point is readily endorsed by Patten. "While there is a possibility that some manufacturers are overly cautious nowadays, you really don't want to be taking a gamble on the freshness of certain products, like meat, because of the risk to your health in making the wrong judgement," she stresses. "Although people are confused, it really is quite simple: only the 'use by' date relates to food safety and so to people's health."

The dating game: What's safe to eat

Use by: It is a legal requirement that this date is carried on all perishable products (dairy, fish and meat). "Use by" dates are set by food company scientists who calculate the perishability of every product by examining, for example, how quickly bacteria grows on a food. These studies must be backed up with published data on similar foods.

Best before: The only other date label required by law, "best before" is carried by non-perishable, cupboard- storable goods and denotes the period during which food is at optimum quality. After the "best before" date a food may lose its flavour or texture. It is not a label that relates to the safety or otherwise of consuming a product.

Eggs: are the one exception to the rule.The EU directive that enshrined the "use by" and "best before" labelling requires eggs to carry a "best before" date. However consumers are advised to treat that guidance as the date eggs should be used by. This is because eggs can contain salmonella bacteria, which could start to multiply after this date, the UK Food Standards Agency explains. It is illegal to sell eggs beyond their "best before" date.

Display until, sell by: Neither of these two date labels was ever intended as a guide to the shopper and consumer. Both were created by the food industry to make retailers' stock rotation easier. After recent calls by Environment Secretary Hilary Benn for both to be dropped, a food industry working party will publish its response next month.

Freeze on day of purchase: This label is carried by many packaged fresh meats and fish. However freezable food can in fact safely be frozen up to its "use by" date, as long as it has been stored correctly in the fridge since the day of purchase, WRAP advises.

Suitable for freezing: Many foods not marked as suitable for freezing can in fact be frozen quite safely. Although the structure of some foods that are high in water content, tomatoes, for example, changes at low temperatures, they can still be frozen for use in soups or sauces at a later date. According to WRAP's Love Food Haste Waste campaign, also freezable are: left-over cream, hard cheese and wine (for cooking); and milk, yoghurts and eggs (beat then freeze, or freeze yolks and whites separately with a pinch of sugar or salt).

Getting the most from your fridge: Fresh salad and vegetables stored in the fridge keep longer in sealed bags or plastic boxes. For safest food storage, the temperature of your fridge should be kept at below 5C at all times, the Food Standards Agency advises.