Pet
Food
Review

Shelf Life & Best Before Dates for Dry Pet Foods

When a dry complete dog or cat food is manufactured, the factory usually pop a 12 month best before date on it, which presumably is meant to

1) reassure the customer that the food will keep fresh for that period of time, and
2) let the customer make a choice at the pet shop as to whether the food has been hanging around too long in someone's warehouse.

Canned food is different, as the canning process kills off any spoilage organisms and excludes oxygen which might cause the food to go off.

But why a 12 month BB date on dry food? What confidence can we have that the food willl indeed stay fresh for that length of time?

Well, several things affect the quality of food during storage, and can have an adverse effect on the nutritional quality of the food - and in extreme conditions possibly even cause ill health in your pet!

The main enemies are MOISTURE (HUMIDITY) AND TEMPERATURE and these can cause the food to go off (rancid) or, if the packaging is porous give rise to mould growth on the kibble.

The type of packaging material can also affect quality. Polythene if it does not have perforations incorporated can cause sweating in hot conditions, Paper can tear more easily and allow moisture in.

Both mould and the by-products of rancidity are not welcome in a pet's diet - the chemicals they create may possibly lead to ill health (see this article)!

Now common sense tells us that if you leave chicken fat out of the fridge it doesn't take long to start smelling. The same is true of vegetable oil which has been used in cooking.

So manufacturers have to stop the fat going off and they use chemicals (antioxidants) of one type or another to achieve this end. There are powerful antioxidants such as bha and bht which are so good that you can almost guarrantee that the food will survive most adverse conditions, and there are so-called 'natural' antioxidants (which are also technically chemicals) which are not as strong, seem to be less toxic BUT are apparently less effective at stopping the fats going rancid and the food going off (see article on antioxidants).

So there's the dilemma! Do we accept a food that is perfectly safe from the point of view of rancidity, but contains powerful antioxidants (which some pet owners don't like to see in the ingredient list) OR do we accept a food which is sold as more natural, but may be exhibiting signs of rancidity and might not be quite as healthy as we think!

Our advice is that if you are concerned about the use of powerful antioxidants and prefer to feed foods without them, that you insist that the food you buy has around 8 months left on the Best Before date. That still means it was made 4 months ago and you've no idea how hot or humid the warehouse was in which it was stored, but you are at least using a reasonable level of caution!