I'm an inveterate eater of suspicious foods and am suspicious of most food that I eat. The first action that I take when I pull anything from the refrigerator is to sniff it. I'm still not sure whether to attribute this to rank curiosity or a well-honed survival instinct. It is a knee-jerk rational behaviour to overcome my primal urge to eat weird things.

If I ate much processed food, a simpler way would be to read the use-by dates and defer the use of my senses to someone else's unseen judgment. Over at Slate, Nadia Arumugam, unpacks what Americans mean by use-by and best-before dates on packaged food, which it turns out, is not much at all.

That dates feature so prolifically is almost entirely due to industry practices voluntarily adopted by manufacturers and grocery stores. As America urbanized in the early 20th century, town and city dwellers resorted more and more to processed food. In the 1930s, the magazine Consumer Reports argued that Americans increasingly looked to expiration dates as an indication of freshness and quality. Supermarkets responded and in the 1970s some chains implemented their own dating systems. Despite the fact that in the '70s and '80s consumer groups and processors held hearings to establish a federally regulated system, nothing came of them.

The American system differs between states for different foods (Milk for instance, is governed by twenty different states' rules) and has vendors scrambling for ever more confusing nomenclature - "Sell by", "Best if used by" and "Best if purchased by".

Australia has a much saner system - our food standards mandate that a "use-by" date is the last date when a food can be eaten safely, if stored under the conditions marked on the package. After this date, food can't be sold.

The "Best before" date is the last day when a food can be "expected to retain all of its quality attributes". After the "best before" it is still safe to sell and eat, but qualities such as taste, appearance, odour or texture may have started to decline. Hence the need to sniff at things.

Neither "best before" nor "use by" dates are required for foods with a shelf life of two years or more - they still need a date of manufacture - but the assumption is that you're either not going to be hoarding for longer than this or possibly, that if a food that lasts for two years goes off, it will be readily apparent to the average diner. Canned foods can keep for up to five years when stored in a cool, dry place, as long as the tins remain undamaged which is why they rarely carry a use-by date. Honey has an indefinite shelf life.

The oldest marked food that I could disgorge from the pantry was a three year old tin of golden syrup, and it was not any worse than a more recent jar. It was a stark reminder that I should eat more golden syrup.

Whatever their format, use-by dates are little protection from the worse worse threats to health carried by food. Spoilage bacteria (while not often delicious when uncontrolled) tend to be less of a threat to health than from food contaminants that carry salmonella and listeria. Foods that are well within their use-by dates remain unprotected.