How Can Dog Treats Last for Months Without Preservatives?

Leave a piece of fresh chicken on the kitchen worktop and you wouldn't dream of feeding it to your dog next week. Yet some dried meat treats can sit on a shop shelf for months without any added preservatives.

What's stopping them from going mouldy?

Often, it's something remarkably simple: the meat has been dried until microorganisms no longer have enough available water to multiply. Drying is itself a method of preservation.

It's not just how much water is in the food

Bacteria and mould need water to grow. But here's the surprising bit: water can still be present in a food without being readily available to them.

Food scientists measure this using something called water activity. It's different from the moisture percentage you might see on a dog-treat packet.

For a sense of the difference, fresh meat has a water activity around 0.99 on a scale ending at 1. Bread is around 0.95. A dry biscuit can be around 0.3. It's one reason a slice of bread can go mouldy while biscuits often last much longer in the cupboard.[1]

Different microorganisms tolerate different levels of dryness. But reduce water activity sufficiently and they cannot grow, even though some water remains. Properly dried meat can therefore have a long shelf life without added preservatives.[1][2]

The important number isn't how dry a treat feels in your hand, or its moisture percentage on the label. It's whether the finished food has been made and kept sufficiently dry, alongside the other food-safety controls it needs.

Does drying actually kill bacteria?

Not necessarily. This is the less obvious part of the story.

A bacterium that cannot multiply isn't necessarily dead. The US Food and Drug Administration warns that drying does not reliably kill Salmonella. It can survive in dry conditions even when it cannot grow there.[3]

That is why making safe dried meat involves more than simply leaving meat to dry. Manufacturers need appropriate raw-material controls, hygienic handling and processing designed to control hazards. The necessary steps depend on the product and how it is made.[4]

So “air-dried” describes a preservation method. By itself, it is not proof that every harmful microorganism has been eliminated.

Can dried dog treats go mouldy again?

Yes. Drying doesn't create a permanent forcefield.

Dried food can take up moisture from humid air. If enough water becomes available again, mould and other spoilage organisms may be able to grow. Opening a bag can increase exposure, although packaging materials differ in how well they keep moisture out.

There's a simple rule for the cupboard: keep dried treats somewhere cool and dry, away from steam, damp shelves and direct heat. Follow the particular pack's storage instructions, keep it closed as directed, and handle the treats with clean, dry hands. Keeping the original label is useful too, especially for the best-before date and batch number.[5]

If treats become damp, grow unexpected mould, or develop an unusual smell, don't feed them. Throw them away. And don't assume that a treat is safe indefinitely simply because it still looks dry.

There isn't one reliable “use within X days of opening” rule for every dried chew. Products differ, and the instructions on the particular pack should come first.

If drying works, why add preservatives at all?

Not every treat is dried to the same extent. Softer, moister treats may need other ways to control spoilage.

And mould isn't the only problem. Fats can react with oxygen and become rancid. Antioxidants, including some used as preservatives, can slow that process. Preventing bacterial growth and preventing fats from going rancid are different jobs.[6]

Added preservatives aren't automatically bad. Equally, a product doesn't necessarily need added preservative ingredients to keep well. “No added preservatives” tells you what's been left out of a recipe, not whether it's been manufactured and stored safely.

At Bounce & Bella, our rule is no grain, no vague derivatives and every ingredient clearly named. A short ingredient list should be exactly that: a clear account of what's in the treat. It needn't be a mystery how the treat stays fresh, either.

Sometimes the answer is simply that drying does the preserving.

Useful next reads

Sources and footnotes

  1. USDA Agricultural Research Service, Water Activity in Food. Explains why moisture percentage differs from water activity, with typical values for fresh meat, bread and biscuits.
  2. Food and Agriculture Organization of the United Nations, Manual on Simple Methods of Meat Preservation, section on water activity. Explains the shelf stability of properly dried meats and why processing conditions matter.
  3. US Food and Drug Administration, Get the Facts about Salmonella. States that drying generally prevents bacterial growth but does not reliably kill Salmonella.
  4. Food and Agriculture Organization, Manual on Simple Methods of Meat Preservation, Section 2. Discusses raw-material checks, hygienic production and careful drying. General dried-meat guidance, not verification of any B&B product.
  5. US Food and Drug Administration, Proper Storage of Pet Food & Treats. Recommends cool, dry storage and retaining original label, lot and best-before information.
  6. FEDIAF, Additives. Explains that preservation controls vary by food type and antioxidants help stop fats oxidising and becoming rancid.