07/13/2014 10:50 EDT | Updated 09/13/2014 05:59 EDT

Don't Trust Your Nose to Detect Rotten Food

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Food aromas are cherished memories. You probably still fondly remember the amazing smell of apple pie or steak from the backyard barbecues of your childhood. While we enjoy smells we like, we also rely on our olfactory prowess to save us from eating spoiled food. In fact, for many the sense of smell is our first line of defense against eating bad food -- but how much can we rely on our sense of smell?

Smell is perhaps the least appreciated of all our senses but the sense varies greatly between people. One large study showed that almost one out of every five people has a significant problem detecting smells. Women have a generally better sense of smell than men. Other factors like poor self-perception, head trauma, and pregnancy can also affect our ability to smell.

Everyone's sense of smell deteriorates with age. I was horrified when my elderly grandmother happily drank spoiled milk since she was unable to detect the sour smell. Did this put her at risk of getting food poisoning?

Not really -- according to US Department of Health -- many of the pathogens that cause food poisoning do not affect the taste, look, or smell of food in any way. Although your sense of smell may raise alarm bells, it will usually fail to warn you of food contaminated with truly nasty pathogens that cause serious illness.

Until 1998, the Food and Drug Administration resorted to a "sniff and poke" method to determine the quality of meat in slaughterhouses. It was only after the arrival of modern food safety control systems that this technique was discarded. Poking and sniffing can definitely identify signs of decay and food spoilage, but it cannot ascertain presence of much more harmful pathogenic agents. Bacteria in spoiled food imparts an unsavoury odor that makes your meal smell very unappetizing but experts say that, despite this unpleasantness, this food is not very harmful if consumed. On the other hand food contaminated by pathogenic bacteria or viruses often smell absolutely divine but can be very dangerous if eaten.

Of course, this does not mean that we should go ahead and eat food that smells off but it does mean that we should not assume that food that smells okay is safe to eat. Each year millions of people fall victim to food borne diseases and many of these illnesses are caused by our tendency to rely too much on our sense of smell.

Next time you're wondering if that food in your fridge is spoiled, don't pay too much attention to the smell -- just toss it out if it's expired.


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