My wife bought some beef mince (ground beef) from a shop. It looked red.

When she fried it, it give off an aroma of vinegar. Is it spoiled?

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    I've never had a vinegar smell come from good beef mince (ground beef for those in the US). I don't know what could cause it but I would throw it away and warn the store. – GdD Sep 30 '14 at 8:06

The smell indicates a safety problem. There is no reason to add vinegar to meat (unless you bought already marinated meat, but 1) marinating mince is so unusual, the chances of finding premarinated mince are against zero, and 2) this would have been declared on the label.

The likely source for the smell is bacterial fermentation. Many bacteria produce acetic acid as a waste product (this is how vinegars gets to smell like vinegar). While the vinegar producing bacteria usually colonize other types of food, and meat tends to support bacteria producing other odors (the ones known as rotting meat), strange things can happen, and this smell is a big red flag. Especially with mince meat, which supports much more bacterial growth than a slab of whole meat (bacteria live on the surface only, more surface=more bacteria).

it looked red

This doesn't matter. The color of meat is not a reliable indicator for food safety. First, meat exposed to air quickly gets an unappetizing shade of green or grey. Second, because customers are known to turn up their noses at greenish meat, butchers can just package it under a special atmosphere, or just bathe it in chemicals which prevent discoloration, so it always stays red. Third, while meat does indeed change its look when it rots, this happens rather late in the process. Gas production (smelly or not) will come much earlier, and you should discard it at that point.

  • Mince, before used-by, was bought from a normal shop in Japan (can't buy from two shops now). We didn't get significantly sick from this- I have a lot of food sensitivities so I get a gas a lot. – user2617804 Oct 1 '14 at 1:25
  • It doesn't matter if you got sick from it or not. "Safe" is about a chance of getting sick, not the certainty that you will get sick. It's like running with scissors, most kids who do it don't stab themselves. As for "before use-by", this is indeed good, but assumes standard storage conditions. If something went wrong anywhere in the supply chain, bacteria can still grow. But I'm glad to hear that everything ended well this time. – rumtscho Oct 1 '14 at 5:50
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    OP says the vinegar smell was detected when it was fried. If it was bacterial fermentation, shouldn't the smell be detected before frying? – Nav Dec 30 '18 at 9:31
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    @Nav the matter is far too complicated to be making simplistic predictions when something should and should not happen. It is entirely possible that there was acetic acid present before the frying - maybe the cook didn't notice it before, maybe there was wrong communication between the cook and the OP, maybe the smell was faint and only got noticeable once heat made it more volatile... The food safety rule is: if you cannot prove that a symptom is harmless, your food automatically becomes unsafe. – rumtscho Dec 30 '18 at 10:56

Probably. Beef should have a faintly sweet meaty smell. An acidic or vinegary smell is never good. I'd chuck it and/or take it back and get a refund, providing it was still supposed to be in date.

With any question of food safety, you have to make the trade off between your willingness to contract food poisoning and the cost of the item involved. Minced beef would cost, perhaps, £5 tops? Which would you rather, lose £5 (assuming you can't get a refund) or spend a few days in bed/in the bathroom being violently ill?


If the meat is not spoiled, the reason might be that the animal was stressed before killing: The smell can be from lactic acid or its decomposition products.

Other reason, yet not very probable, is that the animal was underfed and suffered from catabolic condition - this could be the case with a milk cow.

Or perhaps the meat was just stored in a wrong temperature: Minced meat gets very fast spoiled when the cold chain breaks.

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