An interview with filtration specialist Scott Grimes
The pet-food market grows by several billion dollars every year. In 2014, pet-food sales amounted to 50 billion dollars, and a year later this figure increased to 54 billion dollars. This is happening not only because of the increase in the number of pets but also because their owners choose higher-quality products.
For this reason, many large pet-food manufacturers have begun to exceed the requirements of the standards of the US Food and Drug Administration (FDA) in force in this industry. Companies have begun paying attention to non-mandatory standards developed for the production of food for humans. Compliance with rules and standards such as the international Safe Quality Food (SQF) standard, the Canada GAP food-safety program and the standards of the British Retail Consortium (BRC) allows pet-food manufacturers to minimize contamination and present their products in a favorable light.
The filtration of air, steam and liquids used in the production of pet food, along with the use of high-quality ingredients, plays an important role in ensuring compliance with the requirements of such standards. Although filtration cannot completely remove all possible contaminants from the environment, it prevents contaminants from entering the feed or the surfaces in contact with it.
It is important to ensure filtration at 3 points of the production process.
These critical control points are listed below.
- Supply points: places where air, steam or liquids are supplied or produced, for example a utility room or a storage room.
- Points of contact with feed: located downstream, where air, steam or liquids come into contact with the feed or the surfaces in contact with it.
- Points of last opportunity: places where there is a last opportunity to retain contaminants that, if they enter the packaging, can cause irreparable harm to the product.
To reduce the potential risk of contamination at different points of the process, redundancy must be used. The saying "Don't put all your eggs in one basket" is also true with regard to filtration. In addition, multi-stage filtration is more economical, since pre-filters at the supply points remove coarse contaminant particles that would quickly cause wear of the more expensive filters at the end points of use.
Follow these basic rules and the following additional recommendations regarding the filtration of air, steam and liquids. (For recommendations on choosing filters, see the pet-food filtration scheme below.)
Air filtration
Compressed air is used to operate production equipment, dry equipment after washing, as well as for the pneumatic transport of products through pipelines. Air compressors often become sources of oil and moisture leaks (an ideal environment for the growth of bacteria) and release metal flakes during wear.
The international Safe Quality Food (SQF) standard contains the following requirement: "compressed air and other gases used in the production process must be clean and pose no threat to food safety." The standards of the British Retail Consortium (BRC) specify that the quality of air "in direct contact with ingredients… should be controlled to prevent the risk of contamination. Compressed air in direct contact with the product must be filtered."
Donaldson recommends installing several filters at the compressor outlet. Such a set of filters should include a pre-filter (5 microns) to remove coarse particles; a coalescing filter to remove most of the moisture, as well as a 0.2-micron fine filter to retain small contaminant particles. To remove water vapors, which can become a favorable environment for the growth of microorganisms, an air dryer with a desiccant is installed downstream.
Liquid filtration
Water is used in pet-food production for a wide variety of purposes, from cleaning equipment to being included in the product and mixing ingredients. Water is also fed into boilers for product preparation, used for mixing and adding gravy; finely atomized water is used to apply vitamins to granules.
Before feeding supposedly clean tap water into the process, it must be passed through a pre-filter. Downstream, fine water filters should be installed for washing, product preparation, mixing and injection. Sterile source water will reduce the likelihood of contamination and ensure product uniformity.
At enterprises where water is sterilized by high temperature or passes through a reverse-osmosis system, pre-cleaning of the source water will prevent the formation of an organic biofilm on expensive equipment.
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Filtration solutions in pet-food production
Our solutions for cleaning liquids, steam and sterile air allow pet-food manufacturers to minimize the risk of product contamination and ensure compliance with the requirements of regulatory bodies from the start of the process to the packaging of the finished product.
Steam filtration
Steam is excellent for preparing products, since it maintains precise temperature control by regulating its pressure. Steam can be fed directly into the product to defrost or cook it, or to heat the shell of a food raw material. Some types of feed are extruded with high-pressure steam to form granules or pellets. Steam is also used to cook feed after it has been packaged in cans.
Due to the use of strong cleaning solvents, steam boilers can over time become a place where contaminants accumulate, which can worsen the condition of the equipment. To protect products and equipment from by-products, steam filtration can be used. The same applies to spray balls on steam injectors. If the steam lines are not equipped with filters, the small openings of the spray balls can become clogged with contaminant particles.
In places where steam comes into contact with food products, it is important to use culinary steam. This rule came from dairy production, where 3-A sanitary standards require the use of culinary steam with the removal of 95 % of particles 2 microns in size or larger.
Conclusion
The website of the US Food and Drug Administration (FDA) provides information about cases of pet-food contamination. The latest reports contain data on cases of mass Listeria and Salmonella infections, naming the companies involved. To protect brand reputation from risks, many feed manufacturers are beginning to use standards in force in the production of food for humans.
Contact the experts of Donaldson's process filtration division to get help in creating a filtration plan. We have already helped some of the largest pet-food manufacturers switch to stricter quality standards.
