Extruded Kibble
Definition
Commercial dry dog food is usually sold as extruded kibble. Dry dog foods are made from a mixture of ground ingredients, such as meat meal, grain flour, fats, vitamins and minerals. These ground ingredients are mixed together to form a dough-like consistency. The dough is then heated under steam pressure in an extruder barrel at temperatures of 120–160°C. As the mixture is forced out of the end of the barrel it is cut to various shapes. The shapes will have inflated whilst in the barrel due to the high pressure, but return to their original form as the pressure is released. The dry food is now gelatinised (making the starches digestible) and pathogen destroyed. The food is then cooled and coated with an aid to prevent drying out in storage. The moisture level of such a product is around 8–10%.
Expanded Body
The first commercial production of pet food by means of extrusion technology took place in the 1950s by Ralston Purina in the United States. In the 1980s the extrusion technology had become the standard for production of dry dog food world wide. Most of the dry dog food manufacturers in India like Drools, Pedigree (Mars Petcare India) and Purina use twin-screw extrusion technology for manufacturing of dry dog food. The twin-screw extruder is a single step processing system, which mixes, cooks and shapes the dough into required form. Temperatures as high as 120–160°C and pressures of 30–80 bar are developed leading to starch gelatinisation of 75–95% and pathogen reduction comparable to pasteurization.
The kibbles are put through rotary drum dryers to lower moisture content. In this form, they are sprayed with fat and with palatability enhancers (chicken digest, beef digest, or fish digest) to hide the unacceptable taste that the kibbles acquire through the extreme heat that is involved in their processing. All FSSAI certified kibble manufacturers in India test their extruded dog food in NABL accredited laboratories (like CFTRI, Mysuru) for presence of pathogens under Standard 2.2.10. They check for the absence of salmonella in 25g test samples and also check for the presence of presence of aflatoxin which should be less than 10ppb before they can be put in retail.
Quick Facts
| Metric | Value |
|---|---|
| Process Temp | 120–160°C |
| Pressure | 30–80 bar |
| Starch Gelatinisation | 75–95% |
| Final Moisture | 8–10% |
| Shelf Life | 12–18 months |
EXTRUSION VS BAKING VS COLD-PRESS — DOG FOOD FORMATS
| Format | Process Temp | Nutrient Retention | Digestibility | Shelf Life | India Availability |
|---|---|---|---|---|---|
| Extruded Kibble | 120–160°C | Moderate (vitamins added post) | High (75–95% starch gelatinisation) | 12–18 months | Widely available |
| Baked Kibble | 160–200°C | Slightly lower (higher heat) | Moderate-High | 12–18 months | Limited (Canagan, Orijen Baked) |
| Cold-Pressed | 40–80°C | High (lower heat) | Moderate | 6–9 months | Very limited in India |
| Air-Dried | < 75°C | Highest (minimal heat) | High | 18–24 months | Very limited in India |
Related Terms
Faq
Q: Is extruded kibble less nutritious than raw or fresh dog food?
A number of people have tried to express the digestive value of even the best extruded kibbles. The best examples for Drools, Royal Canin and Purina kibbles are approximately 82-88% for protein. This is as opposed to 85-92% for protein from individual, fresh, cooked ingredients. There are no clinical instances of deficiency with even the worst of commercial pet foods under typical feeding circumstances. The vitamins and amino acids that are destroyed in the extrusion cooking process are always 100% supplemented after the cooking process has been completed to ensure that the final product is completely AAFCO-complete.
Key Takeaways
- Cooking dog food at 120–160°C leads to gelatinisation of 75–95% of starch, forming an easily digestible feed base which can also function as a vehicle to kill all pathogens thus forming the major global and Indian dog food format, i.e. dry kibble or extruded feed.
- The coating with digest spray after the processing in the extruder brings back the smell and taste that is lost in starch gelatinization at high temperatures.
- All the kibble manufacturers in India who are FSSAI certified, namely Drools, Mars Petcare and Purina India use Twin Screw Extrusion Technology to make their respective dog foods.
- There is a marginal nutritional difference between the digestible protein content in an extruded premium kibble (82-88% or more) and fresh food (85-92% or more).
