dog and cat eating from double bowl

Irradiated Pet Food


This article is written by Pet Circle's qualified veterinarian, Dr Gillian Hill, BVSc (Hons)

What is irradiated pet food?
Why is some pet food irradiated?
How does gamma irradiation work?
What is the evidence regarding the safety of irradiated foods?
Which pet foods are irradiated?
Is irradiated food safe for pets?
Further reading

What is irradiated pet food?

'Irradiated pet food' refers to pet food products that have been subjected to a sterilisation procedure by exposure to either electromagnetic radiation (most common - using Gamma irradiation or x-ray ionising radiation), or particle radiation (less common - using electron beam).

Irradiation has been used in the food industry in many countries to extend the shelf life of food by reducing the population of bacteria in the finished product. The option of irradiation is not available as a biosecurity import measure for food for human consumption unless supported by the Australia New Zealand Food Standards Code.

Why is some pet food irradiated?

Australia has some of the most biodiverse environments in the world. Our biosecurity policies are designed to protect these pristine environments, and keep Australia free from harmful pests, diseases and weeds.

Pet food products can pose a risk to our country as they may contain disease agents or pests that are exotic to Australia. Irradiation of pet food products is currently accepted by the Australian Department of Agriculture, Fisheries and Forestry (DAFF) as a "biosecurity treatment for a range of products of animal origin"1, in order to address biosecurity concerns about the product. This is "especially the case where a product does not meet Australia's biosecurity requirements, the product has not been adequately processed or tested to address Australia's biosecurity concerns, or where the manufacturer is unable to provide the department with sufficient information to complete the risk assessment."1

How does gamma irradiation work?

In the pet industry, heat treatment and irradiation are the only options for managing food safety risks. Both treatments have the potential to affect the characteristics of the food, including dose-related effects on certain nutrients, and the production of radio-lytic byproducts.

Gamma irradiation is the predominant type of irradiation used for food treatment. It is a type of electromagnetic radiation originating from either cobalt-60 or caesium-137 (cobalt-60 is the main type in use).

When cobalt-60 decays, it becomes nickel, and emits 2 high energy gamma rays which have great penetrating ability, similar to x-rays. These rays can pass through both high and low density products, including those in their final packaging.

When the gamma rays are absorbed by the food product, the atoms in the product become ionised (transformed to a charged or unstable state), and this results in the breakdown of the chemical bonds within the food. This process affects the DNA of any microorganisms within the food, rendering them non-viable. However, this process can also produce free radicals, and can result in the loss of nutrients in the food.

The macronutrients in the foods (carbohydrates, fats and proteins) have not found to be significantly affected in terms of nutrient value and digestibility by treatment with irradiation. However, some micronutrients, such as vitamins A, E and thiamine, can be particularly sensitive to irradiation, and an increase in the oxidation of the fats in animal feeds has been found where the product has been treated with a dose over 25 kilogray (kGy). Currently, the level of irradiation required for pet food products is set at 50 kGy. Because of this, irradiation as a biosecurity option is not supported by DAFF if the products are likely to make up a significant portion of an animal's diet, such as dry kibble.

It is important to note that the gamma rays are well below the threshold for photonuclear activation of any chemical element, so no radioactivity can be induced in the treated food.

dog eating from white bowl

What is the evidence regarding irradiated food safety?

There have been numerous studies looking into the safety of irradiated foods. Some of these are:

Studies have confirmed the general safety of irradiated food at doses typically used for product for human consumption (i.e. <10 kGy). However, due to the significant reduction in some vitamins, other nutritional factors and increase in lipid oxidation at doses over 25kGy, irradiation of foods that will be consumed as a significant part of an animal's diet (e.g. kibble) is not supported by DAFF.1

Which pet foods are irradiated?

Numerous studies have shown that irradiated pet food is not safe for consumption by cats. The use of gamma irradiation for imported cat foods and treats is therefore no longer offered as an option for importers as of 200913, and in line with this, we do not recommend feeding cats any irradiated food products.

For multi-pet households, care must be taken to prevent cats from consuming any irradiated dog food products.

In approving the import of pet foods, DAFF assesses the risk of those foods based on the country and species of origin of each ingredient, and the processing of those ingredients and the final product.

If the product and/or it's ingredients have been heat treated sufficiently (according to regulations), the import is approved. For those dog food products which do not meet the requirements, importers have the option to irradiate the foods.

If importers choose to irradiate their products, the Australian Standard for the Manufacturing and Marketing of Pet Food requires that the product will be labelled 'must not be fed to cats'.13

Is irradiated food safe for dogs?

Irradiation is a method of ensuring food safety and minimising the potential risk of pathogenic bacteria, viruses and food-borne parasites to your dog. There are currently no studies linking irradiated dog food products to any ill-health effects in dogs. Along with pathogenic bacteria, metals, pesticides, illegal dyes and more, irradiation is being investigated by the US Food and Drug Administration, as one of many potential causes of illnesses in pets relating to jerky treats. At this stage however, their testing has not implicated any specific agent/s as the cause.

In line with Australian standards and regulations, at Pet Circle we do not sell any irradiated food products for cats, or any irradiated complete and balanced dog foods.

We recommend limiting the amount of treats to no more than 10% of your pet's daily calorie intake (whether irradiated or not for dogs) to ensure that their overall diet remains complete and balanced. Keep treats as just that - a treat for good behaviour, a well-deserved reward. Shop from our range of Australian-made dog treats and cat treats for treats that align with Australian standards of food-safety and manufacture.

Further Reading

How To Spot A Good Pet Food

Australian-made Pet Products

What are the Best Pet Treats?

How Much Should You Feed Your Pet?


1Department of Agriculture. 2014. Gamma irradiation as a treatment to address pathogens of animal biosecurity concern. Department of Agriculture, Canberra. Accessed 4 April 2023

2World Health Organization. 1994. Safety and nutritional adequacy of irradiated food. World Health Organization. Accessed 4 April 2023

3Grossweiner 2009. Direct action of Ionising Radiation. Accessed 4 April 2023

4Child G, Foster DJ, Fougere BJ, Milan JM, Rozmanec M. 2009. Ataxia and paralysis in cats in Australia associated with exposure to an imported gamma-irradiated commercial dry pet food. Aust Vet Journal. Accessed 4 April 2023

5Caulfield CD, Kelly JP, Jones BR, Worrall S, Conlon L, Palmer AC, Cassidy JP. 2009. The experimental induction of leukoencephalomyelopathy in cats. Vet Pathol.𝔯_id=ori:rid:crossref.org𝔯_dat=cr_pub%20%200pubmed. Accessed 4 April 2023

6McDowell ME, Raica N, Jr. 1962. Review of the United States Army's irradiated food wholesomeness program. Accessed 4 April 2023.

7Joint FAO/IAEA/WHO Study Group on High-Dose Irradiation (Wholesomeness of Food Irradiated with Doses above 10 kGy). 1999. High-dose irradiation : wholesomeness of food irradiated with doses above 10 kGy : report of a Joint FAO/IAEA/WHO study group. World Health Organization. Accessed 4 April, 2023

8Joint FAO/IAEA/WHO Expert Committee on the Technical Basis for Legislation on Irradiated Food, World Health Organization, Food and Agriculture Organization of the United Nations & International Atomic Energy Agency. 1981. Wholesomeness of irradiated food : report of a Joint FAO/IAEA/WHO Expert Committee. World Health Organization. Accessed 4 April 2023

9Cassidy JP, Caulfield C, Jones BR, et al. 2007. Leukoencephalomyelopathy in Specific Pathogen-free Cats. Veterinary Pathology. Accessed 4 April 2023

11Duncan ID, Brower A, Kondo Y, Curlee JF Jr, Schultz RD. 2009. Extensive remyelination of the CNS leads to functional recovery. Proc Natl Acad Sci U S A. Accessed 11 April 2023

12Radcliff AB, Heidari M, Field AS, Duncan ID. 2020. Feline irradiated diet-induced demyelination; a model of the neuropathology of sub-acute combined degeneration? PLoS One. Accessed 11 April, 2023

13Standing Council on Primary Industries, Pet Food Controls Working Group. 2012. Managing the Safety of Domestically Produced Pet Meat, and Imported and Domestically Produced Pet Food. Accessed 11 April, 2023

14Department of Agriculture, Fisheries and Forestry, PIMC Pet Foods Controls Working Group Report. Enclosure 5, Accessed 11 April 2023.

15Department of Agriculture, Fisheries and Forestry, PIMC Pet Foods Controls Working Group Report. Enclosure 9, Accessed 11 April 2023.

16Department of Agriculture, Fisheries and Forestry, PIMC Pet Foods Controls Working Group Report. RSPCA Position Statement. Accessed 11 April 2023.

17Ian J. Tinsley, Jesse F. Bone, Edward C. Bubl. 1970. The growth, reproduction, longevity, and histopathology of rats fed gamma-irradiated carrots. Toxicology and Applied Pharmacology. Accessed 11 April 2023.

18V. Chalam Metta, M. S. Mameesh, B. Connor Johnson. 1959. Vitamin K Deficiency in Rats Induced by the Feeding of Irradiated Beef, The Journal of Nutrition. Accessed 11 April 2023.

19Ravinder Sialy, R.N. Chakravarti, C.R. Nair & B.D. Gupta. 1976. Effect on the Reproductive Functions of Female Rhesus Monkeys of Feeding Irradiated Wheat Flour and Potato Diet, International Journal of Radiation Biology and Related Studies in Physics, Chemistry and Medicine. Accessed 11 April 2023.

20Caulfield CD, Cassidy JP, Kelly JP. 2008. Effects of gamma irradiation and pasteurization on the nutritive composition of commercially available animal diets. J Am Assoc Lab Anim Sci. Accessed 11 April 2023.