The recent news that UK supermarket chain Morrisons are going to scrap the use-by date on their own brand milk has set many people thinking about what's in their fridge. Can you trust your nose to tell you if the milk is off - and what about some other food hygiene issues? Máirtín Mac Con Iomaire from TU Dublin joined the Drivetime show on RTÉ Radio 1 to talk to Sarah McInerney and Cormac Ó hEadhra about the sniff test. (This piece includes excerpts from the conversation which have been edited for length and clarity - full discussion above).

"I think what's going on here is that milk that has been stored consistently in the fridge can last a number of days longer than what would be traditionally on the use by date", explains Mac Con Iomaire. "Now, naturally milk that has not been correctly stored can go off before the used by date so just because something as a use by date doesn't mean that actually you could use til that time.

"If you've left milk out in the heat or left out in this direct sunlight or something like that, it'll soon curdle. But equally, if it's been stored correctly and it's been in the fridge, it'll last a lot longer. I suppose the issue here is about confidence in linking people back to where their food come from and having an understanding about food and understanding that food can last a bit longer."

Mac Con Iomaire explains that it's not really a risk to public health. "There's a difference between food spoilage, microorganisms as such, which actually cause food to go off and pathogenic microorganisms, which actually cause you to be ill. They're separate issues. Morrison's have done this already with their yogurt and they've done it with some other products that don't really provide that risk because most of these products have been pasteurized already or homogenized. Morrisons have tested this and I think the food regulatory authority or whatever in England are happy enough with what they're doing."

What about mouldy bread, asks Ó hEadhra? Say, sandwiches with mould still on the bread (to the clear consternation of his co-host)? "What you're getting down to there is arguments here about how we've become so hygienic. We used to be associated with a certain amount of dirt. The stuff would fall on the ground, you'd pick it up, whatever, and that would harden you and you'd get used to it.

"We're not saying now that the good people of Ireland should all down mouldy sandwiches. If you are looking at something, look and think about the environment. Think about sustainability and actually ask yourself 'does this really need to be thrown out or actually is this okay to be eaten for another day or two?'