Monday, September 25, 2023
HomeEditorialJoe Kearns - EditorialsMixing, dosing, plant design, standard petfoods, raw materials test for verification

Mixing, dosing, plant design, standard petfoods, raw materials test for verification

by Joseph P Kearns, Editor, International Petfood Magazine

Image Credit: trent roche on Flickr
(CC by 2.0)

Happy New Year to all as we hope 2023 is a spectacular year for all of our readers. Since we are at the beginning of the year lets discuss the beginning of a petfood process.

The raw materials which include all the needed nutrients vitamins and minerals the pets require historically were simple and based on standard available feed style ingredients. Corn soybean meal, wheat mids and meat and bone meal were the main components. Today the sky is the limit for petfood ingredients and many are human food grade. The one element that came along for the ride into pet foods was and still is bacteria. Initially the design and production goal of petfood extrusion was heat pressure and allot of it to get the expansion and cell structure desired. This of course, not by design, eliminated all bacteria off the extruder when 125OC was achieved. As knowledge of the process grew and machinery advanced the science of petfood production and process requirements grew to include elimination of bacteria due the human involvement, touching the product in order to feed the pet.

Standard petfood production in past years was much like making farm animal feeds, basic feed mill designs which were open air and dusty operations. The start of the process in both modern and older plant designs include all the receiving, storage, conveying, grinding, mixing and micro ingredient addition systems. There was not much dust control equipment as mainly the design created dust. Today visits to current technology petfood facilities are generally cleaner than you can imagine. In past years on a trip to Argentina visiting Mars production facilities I met Mrs. Jacqueline Mars. As she passed through the plant. We had a brief discussion and I recall telling her I was impressed with all their facilities in the world. She asked why and I informed here she had the cleanest kitchens in the petfood industry. Obviously, there were others just as clean but in hind sight these companies knew the need for cleanliness, bacteria control, dust control.

Processes in the raw material area, all of them, are quite good at creating dust. Conveying, grinding, mixing etc. all created dust. In the late 60’s and early 1970’s dust control equipment was coming on strong along with pneumatic conveying for raw materials as well as in the production area. These were tremendous in filtering the air and moving products with less dust development or release into the factory. It is now normal to have dust control on grinders, mixers and conveying equipment. Mixers, micro systems and grinders specifically with the addition of air movement control greatly reduced losses of ingredients some of which are quite expensive. Closed loop, air movement, individual systems greatly improving the control of bacteria movement in the plant. Verification of the bacteria in raw materials needs to be assumed as negative as you can bet it is present. Better coefficient of variance of mixers as well as accurate dosing systems created a more homogenous batches insuring all of the kibble included the same nutritional benefits.

Plant designs changes in addition to the equipment improvements where raw material prep and production operations were separated not only the atmosphere between them but personnel movement so as to avoid bacteria’s from following along for the ride. Rooms separation and air pressure of these rooms also reduced dust movement so as guarantees of kibble without bacteria is achieved.

There are now systems which collect samples move them to the lab and automatically place them in testers to ensure product quality without human contact, greatly reducing possible interaction or movement of bacteria on the product after the extrusion or bacteria kill step. Today many fresh products such as mechanically deboned meats are used in the fresh state and considerations for these high bacteria products is also handled by keeping this material in a chill room with only a pipe, sanitary design, going through the wall to the extruder as a separate flow stream. Same for other possible liquid additions.

Having seen plants throughout the years and changes as they developed there are many different possibilities to achieve the desired goals. Separate building for batch preparation with pneumatic conveying to the process building, plants with virtually no windows, controlled entrance points, employee sanitation rooms or stations, methods to clean the plant with verification swabs or test methods for machinery surfaces, machinery designs to reduce bacteria build up with standard operation procedures to ensure priorities are in position and followed.

In this year’s issues we hope to cover many of the abovementioned possibilities. Positive and negative pneumatic systems for powders or raw materials, finished goods as well as between extrusion and drying. Grinding with air assistance and dust control and the same for the other processes involved. Discussions on the end of the extruder kill step verification, dryer moisture control and other topics greatly effecting product quality and bacteria elimination. Having mentioned a number of these topics can you imagine trying to control all of these processes by hand, without some sort of management system such as computer assistance or control. It was not that long ago that the operator of the extruder did it all by hand, started motors, turned steam and water valves, checked the product out of the conditioner before and after the extruder, ran around to be sure the raw material area was giving him what was needed to make a kibble. Have you ever seen an operator struggle to make a product putting tons on the floor due to some sort of situation? How about something so simple as an ingredient was somehow left out which greatly changed the expansion of the kibble. Low steam pressure, no water, product quality off the dryer, how about the coating system is the % added in liquid form correct? Hand checking all flow rates to confirm or predict the outcome. To be honest it was hectic to say the least and one that was worth living through so complete understanding of what is going on understood. This knowledge is used when the current computer systems require an investigation as to what needs to be corrected and/ or be calibrated for accuracy of production. With the modern computer control packages for the entire system all calibrated is a wonder to see in operation. Looking forward to 2023 and all the possibilities in front of us.



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