Food Focus June 2009

Dinner diving dangers

You’ve probably heard the saying ‘one man’s trash is another man’s treasure’, but a small number of people are taking the saying to unsafe extremes.

“Dumpster diving (also called ‘skipping’) has recently been highlighted with the arrest of three Dunedin students, and it’s a practice we would also strongly advise against,” says New Zealand Food Safety Authority microbiologist Roger Cook.

Dumpster diving involves sifting through other people’s rubbish, mostly commercial skip bins, and taking out what someone considers to be perfectly good and usable merchandise.

Generally, this means appliances and clothes but it can also extend to food – and that’s where it worries NZFSA.

While it might be tempting to make a meal from the food others toss out, because of philosophical reasons or hard economic times, there are serious food safety concerns.

“Anybody who eats food from a dumpster is putting themselves as well as the people they share the food with at risk of foodborne illness,” Roger says.

Why supermarkets throw food away

Supermarkets throw away food for a range of good reasons: food may be past its best by or use by date, damaged or subject to a recall.

Most commonly, the food is past its best by or use by date. Best-before dates relate to food quality – food generally loses some of its quality and taste if eaten after this date. Use-by dates are a marker for food safety – food should not be eaten and cannot be sold after this date.

Sometimes, food will be thrown out before it reaches these dates to clear shelf space for newer products – but that does not mean it is safe to consume once in the dumpster. Use-by and best-by dates are dependent on food being stored in the correct conditions, Roger says.

“If it is stored at 4°C in the cabinet, and you throw it into a dumpster with an external temperature of 20°C, the product starts to spoil and the use by date concept goes out the back door.”

Food may be thrown out because it is bruised or its packaging is damaged, allowing bacteria to grow more easily inside.

Food subject to a recall may also be thrown out so it does not pose a health risk to consumers. In New Zealand, if a decision is made to dispose of a recalled product in a dumpster bin, a Food Act officer will make sure the products are marked so it is clear they cannot be sold. They will also open the food and use a pungent cleaner and/or spray paint on it so it is clearly smelt and seen to be contaminated. Dumpsters holding recalled food are generally locked and taken to a rubbish tip as soon as possible.

Dirty dumpsters

Dumpsters can expose food to a range of physical, chemical and microbiological hazards. Who knows what was last in the dumpster before it was carted to the tip, emptied and then dropped off ready for more waste?

Food for disposal can mix with items such as glass shards. It can also get covered in chemicals like cleaning products or motor oil, which may have been discarded into the same skip.

The confined dumpster conditions create a potential breeding ground for flies and bacteria, which can contaminate food and lead to foodborne illness. Campylobacter bacteria, for example, are found on raw poultry and can grow very rapidly in warm, moist conditions like those inside a dumpster.

“Foods that are eaten raw, like lettuces, may have been sloshed with old poultry juices and become cross-contaminated with Campylobacter,” Roger says. Campylobacter is New Zealand’s leading cause of foodborne illness.

Wrapping offers little protection as it may be permeable to some chemicals or get smeared with bacteria from other food. If people do not wash their hands after handling contaminated packaging, they could transmit the bacteria to other food or their mouths, and make themselves sick.

There’s also no guarantee heating the food will kill any bugs as cooking destroys only some of the bacteria that could contaminate food in the trash. Staphylococcus aureus enterotoxin, for example, is not inactivated by cooking, and cooking has little effect on chemical contamination.

Garbage is not food

Once food is dumped, it is exposed to a range of hazards, including cross-contamination from other items and lack of refrigeration, as well as rats, flies and bacteria.

So although it may be tempting to make a meal out of the food your neighbours or your supermarket throw out, it’s simply not worth the risk.

“While food is in a shop or restaurant, it is subject to the food safety programmes or assurances provided by food hygiene regulations,” Roger says.

“As soon as food is out of these controlled conditions, it’s garbage. You cannot treat it as food.”

What the supermarkets say

New Zealand’s two major grocery store groups strongly advise against retrieving waste from rubbish bins, saying there is a serious risk from cross contamination and potential personal injury. The activity could also constitute theft.

Foodstuffs and Progressive say they are committed to ensuring food waste is kept to a minimum. Both groups donate food where possible, under very controlled conditions.

At Foodstuffs, individual stores gift to charities and food banks where the quality and safety of the products can be guaranteed.

Progressive has in the past gifted food to food banks when there is a printing error or small dent in the product but the food quality and safety is not affected.