Preserving

Dr Freeman wrote that preservatives are blamed for causing cancer, kidney disease, pancreatic disease, allergies, hair loss, blindness and immunodeficiency in our pets. Preservatives ensure pet foods keep their long shelf life by preventing fat and other ingredients in the food from oxidising (spoiling), which makes the food not only taste bad, but also unsafe to eat. Canned food requires fewer preservatives than dry food as it is protected from oxidation by its airtight storage.

According to Dr Freeman, pet foods are preserved with either natural or artificial preservatives. Natural preservatives include Vitamin C (ascorbic acid), Vitamin E (tocopherols), oils, rosemary, clove or other spices, just like it was used to preserve foods thousands of years ago.

Some consumers prefer pet foods with only natural preservatives. Vitamin E, vitamin C, citric acid, and rosemary are among the most commonly used natural antioxidants. Mixed tocopherols are a common source of vitamin E in pet foods. Vitamin C is provided by ingredients such as cranberries, blueberries, apples, and some other fruits. Citric acid is also found in many of these, especially citrus fruits. Rosemary is an extract from the plant Rosmarinus officinalis, an evergreen shrub which has anti-oxidant properties.

If you choose to use a dog food containing natural preservatives, keep in mind that they cannot extend shelf life as long as the artificial preservatives can. Consider buying the food in smaller amounts, to make sure that it is used up before it loses its freshness or nutritional value. 

Freeze drying

Freeze-drying—technically known as lyophilisation, lyophilization, or cryodesiccation—is a dehydration process typically used to preserve a perishable material or make the material more convenient for transport. Freeze-drying works by freezing the material and then reducing the surrounding pressure to allow the frozen water in the material to sublimate directly from the solid phase to the gas phase.

Canned Pet Food

Feeding only canned food is another way to avoid artificial preservatives. The canning process is one of the most effective preservation methods available, so no artificial or natural preservatives need to be included in the food itself. Unopened canned food can last for years when stored in a cool, dry environment, although owners should still observe the “best by” dates that are printed on the label. 

The canning process involves placing foods in jars or similar containers and heating them to a temperature that destroys micro-organisms that cause food to spoil. During this heating process air is driven out of the jar and as it cools a vacuum seal is formed. This vacuum seal prevents air from getting back into the product bringing with it contaminating micro-organisms.

From the microbial point of view, it would be ideal to employ very intensive heat treatment which would eliminate the risk of any surviving microorganisms. However, most canned meat products cannot be submitted to such intensive heat stress without suffering

• degradation of their sensory quality such as very soft texture, jelly and fat separation, discolouration, undesirable heat treatment taste and
• loss of nutritional value (destruction of vitamins and protein components).

In order to comply with above aspects, a compromise has to be reached in order to keep the heat sterilization intensive enough for the microbiological safety of the products and as moderate as possible for product quality reasons.

A method was developed for such a balance between food safety and food quality requirements by measuring and quantifying the summary amount of heat treatment to which a canned product is exposed during the entire sterilization process.

Fermentation

Only two types of meat products exist, which are manufactured and normally also consumed without any heat treatment, raw fermented meat products (such as raw ham, dry sausages) and the raw dried meat products (such as biltong, pastirma)

The first step requires creating a favourable environment for the right bacteria to flourish - this means curing the meat and is usually done by salting it are soaking it in a brine.