How Pet Food is Made
Manufacturing pet food comes in a variety of forms, such as wet (can, pouch, tray), dry (extruded or baked), and complementing snacks. Depending on the format, different components and processing techniques are employed.
Wet pet food manufacturing
The components for wet foods are combined and cooked inside the can, tray, or pouch. The food in the container stays sterile until it is opened or until the product has reached the end of its shelf life. These goods can be in the form of mousse, bread, or bits of sauce, jelly, or gravy.
Many of the ingredients used in the manufacture of pet food are described as animal (or fish) derivatives or byproducts. These ingredients are the parts of the animal surplus to the requirements of the human food industry. Examples of by-products include liver, kidney, lung and various meat by-product meals.
Pet foods may also use ingredients legally defined as meat (muscle meat). These ingredients are also most commonly found within the human food chain. In wet pet foods, by-products arrive at the factory in a fresh or frozen state. They may be chopped and added to the recipe mix directly or finely minced, mixed with dry ingredients such as cereals, formed into ribbons and diced into chunks of various sizes and shapes.
Other ingredients are included such as oils and fats, vitamins, minerals, cereals, pasta, grains, or vegetables. Water is also frequently added as an ingredient to facilitate processing and to give the food its final form and texture.
Ingredient weighing and preparation
Ingredients are carefully selected according to a pet food manufacturer’s specific recipe, which is formulated
to deliver complete and balanced nutrition for cats and dogs and also to meet other requirements of the product such as the variety, age range or size range. Once the ingredients for a specific recipe are mixed they enter the can, pouch or tray.
For some forms of wet food, a mix of water, thickening agents and flavours may be added to form a gravy or jelly during the cooking process.
Sealing and cooking
The can, pouch or tray is then sealed and enters a cooking process. The temperature and length of cooking are carefully controlled in order to prevent spoilage over the shelf life of the product, as well as to optimize the taste and protect the required nutritional content.
Cooling and labelling
After cooking products are cooled. Cans are labelled. Information on tray and pouch products is usually printed upon the packaging itself.
Storage and distribution
Individual containers are packed into boxes or trays and stored in warehouses before being dispatched to
Dry pet food manufacturing
Making a dough out of dry and wet materials produces dry pet food. The dough is heated under pressure and then forced through a die cutter during the extrusion process, which creates the kibbles. Size and form of the kibble can vary depending on the product requirements. The kibbles are spray coated after drying and cooling. Other methods of producing dry foods, including baking, besides extrusion, are also possible.
Ingredient selection and sourcing
Many of the ingredients used in the manufacture of pet food are described as animal (or fish) derivatives or by-products. These ingredients are the parts of the animal surplus to the requirements of the human food industry.
In dry pet foods, animal derivatives are commonly used in a meal form (such as chicken meal, poultry by-product meal) where meat and animal derivatives are cooked, the fat removed and the remaining material dried to create a dry meal.
By-products may also be used in fresh or frozen form. Many of the other ingredients such as cereals, grains, and vegetables used in dry pet foods come in dry form and are milled or ground prior to mixing. A recipe is also likely to include oils and fats, vitamins and minerals required to ensure the product delivers all the essential nutrients.
Ingredient weighing and preparation
Ingredients are carefully selected according to a pet food manufacturer’s specific recipe, formulated to deliver
complete and balanced nutrition for cats and dogs. Dry ingredients are ground and sieved where required and then mixed.
Cooking and cooling
The dry mix is combined with wet ingredients, water and steam in a preconditioner, which hydrates the powders, creates a dough and starts the cooking process. The dough then enters a machine known as an extruder, which cooks the dough under pressure. At the end of the extruder the dough exits under pressure through a die plate creating ribbons of pre-specified shape that are then sliced into the pre-specified size using a rotary cutter.
After extrusion and cutting the kibbles are air dried in an oven to remove moisture and then cooled. Reducing the moisture content is an important step in maintaining freshness and preventing food spoilage.
When baked, the dough is rolled out and cut into shapes, then baked in an oven (similar to cookies or biscuits).
After drying and cooling, kibbles often enter a revolving drum where they are evenly coated with a mix of flavours to enhance taste, and preservatives to prevent spoilage through the shelf life of the food. Flavours or other coatings may also be sprayed on baked foods as they exit the oven.
Packs are filled according to the declared weight and the packaging is appropriately sealed to prevent contamination.
Storage and distribution
Packages are stored in boxes or wrapped on pallets and stored in warehouses ready for distribution to customers.
Complementary care and treats manufacturing
Treats for cats and dogs come in a variety of forms. In the EU, the majority are termed complementary as they are designed to complement main meal complete and balanced pet foods. In the US, the same products are generally identified as “treats” or “snacks.” In either case, they should therefore only make up a small percentage of the daily calorie intake.
Feeding recommendations on some pet food manufacturers’ products suggest feeding no more than 10% of
required daily calories. Here are some of the most common ways to make treats for cats and dogs:
- Extrusion: This method involves mixing ingredients to form a dough that is pumped into an extruder. The dough may be a combination of meat and animal derivatives and dry ingredients such as wheat
flour or potato starch that when extruded produced strip like treats. Alternatively, ingredients may
be based on rice flour and wheat starch that when combined provides a chewy, spongy texture ideal
for products that help clean teeth.
- Biscuit baking: The primary ingredient in this process is usually wheat flour. Wheat flour is combined with vitamins, flavours, water and preservatives to make a soft dough. The dough is then cut into the required shapes and sizes before baking in an oven.
- Injection molding: Here ingredients are mixed together before being injected into a shaped mould. After cooling the treats are released from the mould. Moulds are usually used to create specific sizes and shapes of chew.