There is a great deal we don’t know about the manufacturing of pet food. As example, pet parents have long questioned if the manufacturing process destroys or lessens the nutritional value of the pet food. Here are the highlights of a recent study that shows what we don’t know could be harming our pets.
Cooking time and temperature is something I’ve tried to learn from pet food manufacturers, but few of them provided me answers. Many claimed this information was “proprietary“. A new study – Tran, Q.D., et al., Effects of drying temperature and time of a canine diet extruded with a 4 or 8mm die on physical and nutritional quality indicators. Anim. Feed Sci. Technol. (2011), doi:10.1016/j.anifeedsci.2011.03.009 – proves cooking time and temperature could indeed alter a pet food’s nutritional quality.
Kibble pet food is commonly produced by extrusion. Simply put, extrusion is the process of shaping and pressure cooking the kibble by forcing mixed raw ingredients through a die. Extruded kibble must them be dried to remove excess moisture on the kibble surface and interior. “Pet food companies mainly use extrusion cooking technology to produce dry pet foods because of a combination of benefits including better pasteurization, maintenance of nutritional value, flexibility and density control.” Kibble pet foods are “commonly produced at a moisture level between 200 and 300 g/kg and must be dried afterwards to reduce moisture content to less than 60 – 90 g/kg in order to increase shelf-life of the final product.”
This study and previous studies cited in this paper have shown “heat damage to lysine” content of pet food. Lysine is an essential amino acid. AAFCO (Association of American Feed Control Officials) require an adult dog food to contain 1.80 grams per 1000 kcal of lysine and requires an adult cat food to contain 2.08 grams per 1000 kcal of lysine.
“Since drying efficacy depends on the surface area of a kibble, a 4 and 8mm extruder die opening during extrusion were examined. The hypothesis tested was that drying temperatures of 120 ◦C will cause minor and acceptable lysine damage in extruded canine diets.”
But this study did NOT find minor or acceptable lysine damage – in fact, this study showed more than decreased lysine was a concern. “In the present study, the contents of amino acids lysine and proline in the 4mm kibbles were significantly decreased by the high drying temperature.” As well, “High extrusion temperatures may increase the pro-oxidant transition metal concentration, particularly iron, due to the metal wear on extruder parts (Lin etal.,1998).” And “most unsaturated long-chain fatty acids were observed to be decreased in the 4 and 8 mm kibble dried at 200 ◦C.”
In conclusion, this report states “Drying can significantly affect the nutrient content of pet foods. At high drying temperatures (160–200◦ C), lysine damage occurs with reactive lysine decreasing faster compared to total lysine. No other amino acids were affected by drying temperature in the present study except for proline in the 4 mm kibbles, which was increased by drying temperature of 200 ◦C. In addition to amino acids, most unsaturated long-chain fatty acids were observed to be decreased in the 4 and 8 mm kibble dried at 200 ◦C. The drying of extruded pet foods can affect the nutrient composition especially at high drying temperatures. Drying pet foods below 160 ◦C minimizes the negative effects of the drying process on nutrients.”
This study of pet food did not discuss extrusion temperature and time – only drying time and temperature. Until further research is provided on varying extrusion techniques, we do not know if this would alter or damage the nutritional quality. Below you will find a list of pet food manufacturers that provided cooking information. Please note, this is the only information they provided based on our questions (sent prior to this study) of cooking time and temperature.
Addiction Pet Food
Dehydrated food cooked miximum 15 minutes, dry food approximately 17 minutes, can food approximately 1 to 2 hours.
Artemis Pet Food
Cooking information: the heat varies from 100 degrees Celsius to 138 degrees Celsius (212 F to 280 F) between cooking and drying phases and the time varies from 2 to 4 minutes during cooking and 5 to 15 minutes during drying.
Azmira Pet Food
Cooking information: Depending on which formula, it is cooked in accordance with USDA-APHIS requirements to reach: 70C for at least 30 minutes; 75C for at least 5 minutes; or 80C for at least 1 minute.
Blue Seal Pet Food
Cooking information: “some of this information is proprietary”; wet foods are processed at 160 degrees F.
Chicken Soup Pet Food
Dry foods are cooked between 240 to 300 degrees, no information of time provided; canned foods cooked for 80 minutes at 250 degrees.
Diamond Pet Food
Dry foods are cooked between 240 to 300 degrees, no information of time provided; canned foods cooked for 80 minutes at 250 degrees.
Eagle Pack Pet Food
Cooking temperature is 260 degrees F; no cooking time provided.
Felidae Cat Food
Dry pet food is extruded around 210 degrees, and the extrusion process takes around 3 to 4 minutes the product is then moved to the drying process where it bakes at an average of 250 degrees for around 30 minutes. Can Pet Food cooking temperature is about 250 degrees, with approximately a 104 minute cook time.
Fromm Family Pet Food
Dry foods are cooked at 255 F for 50 seconds.
Holistic Select Pet Food
Cooking temperature is 260 degrees F; no cooking time provided.
Life’s Abundance Pet Food
Dry food is cooked at 212 F for 15 seconds.
Mulligan Stew Pet Food
Can food cooked for 50 minutes at 220F internal temp gets to 190F; Kibble cooked for 15 minutes at 220F internal temp gets to 190F.
Natural Planet Organics Pet Food
Food is extruded at 350 degrees F.
Nature’s Logic Pet Food
Dry food cooked at 220F to 250F for a few seconds; canned cooked from raw state for about 45 minutes at 275F.
Nature’s Variety Pet Food
Pet Food cooking: Kibble temperature is a minimum of 180 degrees F for 55 seconds to 1 minute 45 seconds. The product is then transferred to the dryer for 18-23 minutes at temperatures ranging from 200 to 280 degrees. Canning 15-20 minutes at 210F; will vary depending on the product being canned.
NutriSource Pet Food
Food is extruded at 350 degrees F.
Petcurean Pet Food
Dry foods are cooked at 90 degrees F for two minutes.
Pure Vita Pet Food
Food is extruded at 350 degrees F.
Red Moon Pet Food
Dry food is cooked at 90 degrees F for a minimum of ten minutes.
Science Diet Pet Food
The dry pet foods are heated to about 194°F (90° C) during the cooking-extrusion process (would not reveal cooking time for dry food) and canned foods are heated to about 248°F (120°C) for at least 20-30 minutes.
Taste of the Wild Pet Food
Dry food is steam cooked at a minimum of 250 degrees F for 2 minutes, then dried for 30 minutes at 250 degrees F.
Honest Kitchen Pet Food
Meats and eggs are dehydrated above 120F and vegetables, fruits, herbs and grains are dehydrated below 104F.
Wellness Pet Food
Dry foods are cooked at 260 degrees F; no cooking time provided.
Wysong Pet Food
Pet food cooking information: Canned diets are cooked at 247 F for 70 minutes. Our dry, extruded diets are cooked at 180 degrees F for seven seconds.
Wishing you and your pet(s) the best,
Susan Thixton
Pet Food Safety Advocate
Author, Buyer Beware
Co-Author Dinner PAWsible
TruthaboutPetFood.com
PetsumerReport.com
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