Why does cat food stink? This is an interesting question and one that a lot of web surfers ask when looking for an answer through good old Google. People also ask whether they can leave wet cat food out overnight or whether they can leave wet cat food out all day. The answer to both these questions is a profound no.
The first topic is whether we are talking about dry or wet cat food. But before I discuss that issue we have to realise that what stinks to us may be an attractive smell to a cat. To a cat, cat food does not stink (unless it is off). When you read answers to the question in the title people are judging the smell using human criteria. Obviously we can’t do that. I presume that the pet food manufacturers spend a lot of money trying to make their food smell nice to cats. The reason why people judge the smell on human criteria is because they are anthropomorphing their cat. I don’t blame people because cats are family members. Manufacturers support this; they try and make their cat food look attractive to humans and sometimes they describe their pet food in human terms.
The next issue worth discussing is the difference between wet and dry food. The smell from dry cat food is more or less stable. It doesn’t change that much during the time that it is in the cat’s bowl. To me it smells like dry cat food! It smells like the sort of food that a cat would like. That is because it is designed to be liked by cats.
Wet cat food is another story entirely. It is unsuitable for free-feeding. Once opened wet cat food develops an unpleasant smell for humans and their cats. In fact I would go so far as to say that it smells horrible if it is left out in warm weather for an hour or more. I can’t time it exactly but something like that and the food becomes unusable. It needs to be disposed of in a sealed container of some sort to prevent the smell permeating the kitchen and adjoining rooms. Some veterinarians would say that it should not be left out for more than about 20 minutes.
When wet cat food is placed into a cat’s bowl it smells okay to me. It does not smell like human food but it smells all right as cat food; something similar to dry cat food in fact.
Opened cans or pouches of wet cat food should be covered and stored in the fridge. Ideally it should be warmed up to be fed to your cat. I never use cans, only pouches. I don’t think you can store an opened can. It should all be used in one go.
The interesting question that I have is why wet cat food that has gone off smells so horrible. It must be something to do with the chemicals or the ingredients which are in the food. Perhaps it is because some raw ingredients are contaminated with e.g. pesticides on grains or drugs in the dead animals used for cat food. I don’t know. I find the smell disturbing because to me it is indicative of ingredients that are not particularly healthy. I am unable to find out exactly why, on a scientific basis, it smells so awful so quickly.
On an associatd topic, the book on veterinary medicine1 that I have also suggests that cats fed from pop-top cans have a five times greater risk of hyperthyroidism. Apparently the tops contain bisphenol which is a diglycidyl ether. This may be the contributing factor. It appears that research indicates that cats fed on a diet of 50% canned food (wet cat food) have a 3.5% increased risk of hyperthyroidism. That is the first time I have read about that medical issue. It needs more research from me. Can someone add to that statement?
Note 1: Cat Owner’s Home Veterinarian Handbook 3rd edition.