The secret of your pet food CHAPTER 2 LEVEL1
VNA 1 CHAPTER 2 C Contents 1 Quality control 1.1 Ingredients and process..............................5 1.1.a Ingredient specifications..........................5 1.1.b Ingredient receiving and testing procedures..........5 1.1.c Ingredient handling procedures at the plant..........5 1.2 Suppliers.........................................6 1.3 Product quality.....................................6 1.4 Shelf life..........................................7 2 The process of making pet food 2.1 Dry pet food......................................8 2.2 Wet pet food.....................................10 3 Common pet food ingredients 3.1 Carbohydrate ingredients...........................11 3.2 Fibre ingredients..................................12 3.3 Protein ingredients.................................12 3.4 Fat ingredients....................................13 3.5 Additives........................................14 Summary of key points Self-assessment questions 2
L Learning outcomes By the end of this module, you will be able to: summarise and describe the complex process of producing a pet food explain to the pet owner how the pet food is made explain to the pet owner some of the ingredients in the pet food. VNA 1 CHAPTER 2 3
VNA 1 CHAPTER 2 1 Interesting fact Good quality control practices include internal audits of procedures and systems as well as audits by a third party. Quality control To be able to advise owners on pet nutrition, it is important that you are comfortable with the quality of the food you recommend through the clinic. There is no legal requirement for pet food manufacturers to carry our quality control procedures, so any programmes they implement are unregulated and remain the sole responsibility of individual pet food manufacturers. This means that the quality of pet food can vary enormously. You will need to be aware of these differences in order to make judgements on the quality of a food. QUALITY CONTROL Interesting fact One of the things that can really affect quality is if the ingredients vary. Many pet food manufacturers will substitute one ingredient for another. For example, they might use pork instead of chicken, depending on what is cheap in the market at the time. This means it is less expensive for the company to make the food, which may mean they can sell it at a lower price. Some pet food manufacturers have as many as 24 current formulas for one product. Hill s uses what is called a fixed formula. This means that the ingredients do not vary from batch to batch, even though the price of the ingredients may vary. Some pets are very sensitive to ingredient changes and older pets in particular may not like changes to their food. Hill s only changes a formula to improve it or because a certain ingredient is no longer available or fails to meet the high quality that Hill s demands. Let your client know Some companies go to the expense of studying and implementing world class manufacturing processes (benchmarking); others do very little. Some companies use high-quality ingredients; others purchase the least costly ones. Some companies conduct multiple tests to evaluate the quality of raw ingredients and finished products; others do the minimum of what is necessary. 4
VNA 1 CHAPTER 2 The aspects of a quality manufacturing programme: 1.1 Ingredients and process The keys to making high quality pet food are: controlling raw ingredients understanding the raw ingredients controlling the manufacturing process Interesting fact At Hill s Pet Nutrition, the manufacturing process itself has to comply with Best Operating Practices. This means that every part of the process has to live up to a stringent set of quality standards. QUALITY CONTROL This is achieved by: a. making sure that the ingredients delivered to the plant are of the quality you need This includes checking: the purity of the ingredient the condition the ingredient is in after shipping the composition of different nutrients in the ingredient. b. making sure that ingredients are not damaged at the plant handling procedures need to be designed to make sure that all ingredients are handled carefully and gently ingredients should only be stored for the shortest possible time storage conditions must be tailored to the ingredients and monitored carefully. c. making sure that the quality control and all aspects of processing raw materials are meticulously documented. 5
VNA 1 CHAPTER 2 QUALITY CONTROL Let your client know Hill s requires its suppliers to certify (that is, to put in writing) that their raw ingredients will satisfy Hill s exacting requirements. 1.2 Suppliers Pet foods contain numerous raw materials from many suppliers. Because it is so important to get high-quality raw ingredients, a supplier quality programme is critical. 1.3 Product quality Even after having made sure that the raw ingredients are top quality and that they are handled correctly at the plant, manufacturers still need to check that the product they make has a consistent high quality formula. For this to happen, samples of the products should be taken at multiple stages of the manufacturing process. This way, if anything goes wrong, the problem is immediately identified and located, making it easier to correct. Sampling should occur at the following stages: on receipt of each lot of raw ingredients as the product leaves the extruder or the cooker/mixer as the product leaves the dryer after any topical coating packaging of the finished product. To ensure a consistent product quality, a specific sampling frequency needs to be established. A minimum of sampling every 30 minutes is a good start. Let your client know All meat ingredients used in Hill s pet foods are obtained from animals that have been certified fit for human consumption. 6
1.4 Shelf life Shelf life is defined as the amount of time a product maintains its nutritional, microbial, physical and sensory integrity. In other words, a product s shelf life is the time it can be guaranteed to provide high-quality nutrition, with no microbes, without crumbling and with optimum good taste. The expiration date printed on the packaging designates the end of this period. The main cause of diminished shelf life in dry products is oxidation. There are certain things that can be done to reduce the amount of oxidation in pet food: using the freshest possible ingredients (this means that less oxidation has taken place before the ingredient is used) producing the food under carefully monitored conditions using the right packaging materials. VNA 1 CHAPTER 2 Because many things can affect shelf life, such as different storage conditions and physical impact when transported, it is important that shelf life should be evaluated using a number of different tests. Average shelf life is 12 18 months for dry products and 24 months for canned products. QUALITY CONTROL Interesting fact Hill s tests its finished food in a number of ways: samples of every batch are checked for their smell and their appearance the products are analysed chemically to make sure that the level of nutrients is still correct cans and bags are checked to make sure that they are sealed and airtight samples of every batch are stored, so they can be reexamined should any unforeseen problems appear food is fed to dogs and cats to check its suitability, both in owners homes and in Hill s own kennels palatability checks are carried out. In Europe alone, Hill s works with 35,000 individual results per year. 7
VNA 1 CHAPTER 2 2 The process of making pet food Most pet owners feed their pets a ready-made diet. This means that the market is filled with a huge variety of pet foods. Pet foods vary in quality, but most of the premium brands provide the pets with a well-balanced, complete and palatable daily food. THE PROCESS OF MAKING PET FOOD (Above) From start to finish, producing high quality pet food is a complicated process that requires attention to detail. (Right) The same steps are used in bread baking and extrusion cooking. Dry mix hopper Extruder motor 2.1 Dry pet food Mixing Kneading Proofing Shaping Raising Cutting Preconditioner Extruder Knife Assembly The easiest way to look at how dry pet food is made is to compare it to how you make bread. Bread is made in a series of steps and this is also how dry pet food is made. Step 1 Getting all the ingredients together: Ingredients are usually received in large bulks that are then stored until they are needed Some ingredients need to be ground before they can be part of the pet food. Grinding typically makes the ingredient easier to digest and promotes a better and more consistent type of dry food. (Above) Preconditioner. Notice the mixing and conveying paddles that initiate starch gelatinisation and move the dry mix forward. Step 2 Mixing the ingredients: This takes place in the dry mix hopper and the preconditioner. 8
Step 3 Kneading the dough, rising, cooking: This takes place in the extruder barrel Extruders are machines with a screw that propels, mixes and cooks the material. The extruder operates on the principle of friction, which heats and cooks the mixture. Step 4 Cooking and cutting: The final stage occurs when the dough-like material is forced through the openings of the die, which determines final product shape. The die is also the final cooking point in the extruder When the material is forced through the die it resembles a long rope. A knife on the surface of the die is used to cut this rope into smaller pieces, creating the kibbles The material is hot when it passes through the die and when it comes into contact with the cooler air outside the extruder it expands up to 50%, giving the dry pet food its familiar, porous texture. Step 5 Drying and cooling: The kibbles are hot when they come out of the extruder and therefore need to be dried and cooled. This takes place in a dryer. Step 6 Coating: In a similar way that some sweetened breads are glazed after having been cooked, dry pet food may be coated. After this process, the dry product is packaged and sealed, ready to be sold. Interesting fact Good mixing of all the different dry ingredients is essential to making a good quality, consistent pet food. If the ingredients are not mixed properly, it may result in an unequal distribution of essential nutrients or a lack of key ingredients in a product. (Above) Various die inserts. The shape of the die will determine the shape of the dry kibble pieces. The dies shown here will produce oval, round, triangular or fish shaped pieces. VNA 1 CHAPTER 2 THE PROCESS OF MAKING PET FOOD 9
VNA 1 CHAPTER 2 2.2 Wet pet food Wet pet food exists in various forms. Canned wet food is the most common but there has been a recent increase in the popularity of products packaged in tin foil containers or pouches. Such products are often more costly and do not necessarily have any additional nutritional benefits. However, some owners find them appealing despite the added cost. Canning is a process that is dependent on time and temperature. The ultimate goal is to sterilise the contents. This takes place because of: High process temperatures Vacuum conditions in the cans. Pre-heater zone Air cooling zone The canning process is a continuous flow: THE PROCESS OF MAKING PET FOOD Feed leg Can Feed Can discharge Bring up leg (in water) 80 100ºC Steam chamber 116 129ºC Bring down leg (in water) 80 100ºC Cooling leg 18 25ºC (Above) Diagram of tower layout. Cans enter the feed leg, where they are brought up to temperature, then enter the sterilisation leg (steam chamber), and finally the bring-down leg, to go through the cooling process. 1. Wet mix Generally, meats require grinding before canning and sterilisation to ensure a consistent texture and a consistent nutrient mix. 2. Dry mix The wet mix is blended with pre-ground grains, starches, gums, and vitamin and mineral premixes. 3. Steam and/or water: Steam and/or water is added to the mixture. The entire mixture is heated under pressure to specific temperatures (25 85ºC) to gelatinise starches and begin the gentle cooking of protein. 4. Poured into cans: The mixture is poured into a can and steam is injected over the product just before sealing. This displaces the air and after the can is sterilised and cooled, water vapour condenses and contracts, creating a relative vacuum. 5. Sealed and sterilised: The can is sealed with a lid. After sealing, the cans are taken through a machine that conveys the cans into a tower layout. The cans advance through the various legs of the process in a continuous loop, transitioning from water to steam and back to water again. This preserves the food and achieves commercial sterility. Commercial sterility = free from pathogens This means that the canned product does not need antioxidants or preservatives. Sterility is maintained due to the vacuum in the cans. 6. Cooling 7. Labelling and packaging 10
3 Common pet food ingredients In order to make a pet food that is consistent and nutritionally adequate, it is essential to start with ingredients of high quality. Here we will look at the following ingredients VNA 1 CHAPTER 2 CARBOHYDRATES FIBRE PROTEIN FAT We will also take a quick look at the common additives used in pet food. It is important to remember that animals require nutrients, not ingredients. Sometimes pet foods are marketed on ingredient stories that have consumer appeal but this does not ensure the proper mix of nutrients. Ingredients are the means to achieve the nutritional and palatability goals of a product. 3.1 Carbohydrate ingredients The most typical source of carbohydrates is grain. The most common grain ingredients are: Let your client know Both Science Plan and Prescription Diet are made solely from ingredients of such high quality that they can be called, passed fit for human consumption. COMMON PET FOOD INGREDIENTS Maize Grain sorghum Oat Rice Wheat Barley Let your client know Hill s Pet Nutrition ensures consistent quality of ingredients in batch after batch, so all products have the same high quality. 11
VNA 1 CHAPTER 2 Grains primarily add energy to the food, but are also a source of many different nutrients (protein, fat, fibre, minerals, and vitamins). For example, maize is a good source of linoleic acid and also provides essential amino acids and fibre. Rice has a higher digestibility and a lower phosphorus content and still provides valuable fibre. No one carbohydrate is best for every situation, and combinations are often explored to achieve the desired nutrient profile. 3.2 Fibre ingredients Fibre ingredients contain crude fibre between 18 and 80%. Typical fibre ingredients used in pet foods are: THE PROCESS OF MAKING PET FOOD Clinical note Cellulose and peanut hulls are considered more efficient for diluting calories than beet pulp or soy mill run. Soy mill run and beet pulp are considered useful for maintaining gastrointestinal health. Cellulose Soy mill run Wheat bran Beet pulp Peanut hulls Oat fibre Various fibre types can be used to provide distinct functions in pet foods. No single fibre source or type can optimally deliver all the benefits that fibre can provide in pet nutrition because fibres vary from rapidly fermentable to more slowly fermentable. Beet pulp, citrus pulp and soy mill run are good sources of more rapidly fermentable fibre, while cellulose and peanut hulls are a good source of slowly fermentable fibre. Interesting fact Pet food ingredients, including muscle meat, are by nature byproducts. Some of the by-products used in pet foods are ingredients that are considered human-grade, like pork and beef liver, tripe and spleen. Many by-products, like liver, offer superior palatability over muscle meats when used in cat and dog foods. 3.3 Protein ingredients Typical dry protein sources used in commercial pet foods: Poultry by-product meal Lamb meal 12
Fish meal Soybean meal Let your client know The main difference between fresh meat and meat meal on the ingredient list is that fresh meat has a much higher water content. This means that it can be placed first on the ingredient list, making the food appear as if it has different qualities, despite the fact that the nutritional profile is not changed. There is no known benefit of fresh meat over meat meals other than in the owner s mind. VNA 1 CHAPTER 2 Dried egg Protein ingredients vary widely in the levels of protein and other nutrients they deliver to a formulation. Dogs are omnivorous and have lower protein requirements than cats. Therefore, formulations for dogs are more flexible and may include more vegetable protein. Soybean meal is an excellent source of important and tasty amino acids. However, because dogs prefer animal tissue to vegetable meals it is advantageous to add animal source proteins to the formulations. A blend of animal tissue meals and vegetable meals is appropriate and often optimal. 3.4 Fat ingredients Corn gluten meal Fat ingredients contain more than 50% fat. Fat ingredients typically used in pet foods are: Animal fat: pork fat beef tallow poultry fat Vegetable oils: soybean sunflower corn COMMON PET FOOD INGREDIENTS Selection of high-quality fats ensures that the fats are less likely to oxidise quickly and this improves the palatability of the finished product. Antioxidants are necessary to help prevent rancidity during heating of fats and to extend the shelf life of dry products. Some vitamins, minerals and other substances function as biologically active antioxidants. Their function is not to prevent rancidity of the food, but to provide the body with essential support in preventing damage from free radicals. Antioxidants that work in the food have little or no effect in the body. 13
VNA 1 CHAPTER 2 THE PROCESS OF MAKING PET FOOD Definition The terms preservative and additive are often used synonymously but they are distinctly different (See Chapter 3). Preservatives are substances added to foods to retard decay, discolouration or spoilage under normal use or storage conditions. Therefore, all preservatives are additives but not all additives serve a preservative function. Definition Digest is a highly palatable meat extract or essence with concentrated flavours. Digest is used as a palatability enhancer. Interesting fact Most ingredients with unfamiliar, chemical-sounding names are, in fact, nutrients. 3.5 Additives The term additive includes anything that provides increased nutrition, palatability or cosmetic appeal. Additives include: Vitamins Minerals Colouring agents Natural (e.g. carotenoids) and synthetic colours are often added to pet food to enhance consumer appeal. Palatability enhancers In general dogs like fats, sugars, meat ingredients and digests Cats strongly prefer meat ingredients and inorganic acids to fats and sweet ingredients. Emulsifying agents, stabilisers and thickeners Gums, glycerin, glycerides and modified starch are used to prevent separation of ingredients and create the gravy, sauce or jelly portion of moist pet food. Types of gums: alginates (brown seaweed) carageenan (red seaweed) guar gum (ground endosperm of guar plants) xanthan gum (microbial product) sodium carboxymethylcellulose (modified cellulose that is water soluble). Since most commercial pet foods are designed as complete foods, nutrient enrichment with vitamins and minerals is the most important and beneficial use of pet food additives. 14
Summary Summary of key points 1. Quality procedures for pet food manufacturing are neither required nor regulated, but Hill s Pet Nutrition has them anyway. 2. Quality control covers ingredients and processes, vendors, product quality and shelf life. 3. Dry pet food is made in a series of steps like bread. 4. Dry pet food ingredients are mixed in a dry mix hopper and preconditioner, cooked in an extruder barrel and shaped by a die into kibbles. 5. The production of Canned pet food involves grinding meats, mixing grains, adding steam or water, filling cans, and sealing and sterilising the cans. 6. Common pet food ingredients include: grains, fibre, protein sources, animal and vegetable fats and additives, such as vitamins and minerals. Self-assessment questions 1. Why is the grinding process so important in pet food manufacturing? 2. What may happen if the pet food is not mixed properly? 3. How is commercial sterility maintained in canned foods? 4. In general, why is quality control in pet food manufacturing important? 5. What is the purpose of quality control practices for: i. ingredients and processing ii. vendors iii. product quality iv. shelf-life? VNA 1 CHAPTER 2 15
STUFE1 LEVEL1 Trademarks owned by Hill s Pet Nutrition, Inc. 2011 226112 EN 110277