In this issue a good review on palatants results in thinking of coating and applications onto pet foods as a topic. Years ago, it was simply put a bit of number 2 animal fat on the surface and you are good to go as labelled. Systems were crude to say the least as fats were relatively cheap and overdosing was acceptable. As coating costs and sophistication in technology advanced, improved coating techniques developed.
Accuracy is the game as considering the tonnages produced any overage can and is very costly. Instead of check weighing the dry and liquid feeds and operating accordingly we now see automatic weighing systems metering in the dry ingredients, the kibbles and possibly dry powders. With dry flow accuracy pump systems with flow meters and or weight-controlled systems apply the liquids. Liquids applied range greatly from animal and vegetable fat, vitamin mixes both water and oil soluble, meat slurries and palatants. Reviewing the dry material flow, it usually starts with a bin and feeder where the flow discharge is controlled onto a weigh belt for continuous flow or a loss in weight system where the bin and feeder on load cells is monitored and adjusted accordingly. Computer or control systems greatly enhance this operation. The liquid is essentially also weighed to mean the application level needed. The goal is to do this at an acceptable coefficient of variance, even application on all of the kibbles. This involves mixing to allow even coating and improved evenness and absorption time. Types of coaters vary from a simple reel with lifters at an angle so flow passes through the reel as liquids and powders are applied.
Actual enclosed mixers with feeding systems for weighed amounts of both dry and liquids exist. The liquid system can be tanks with flow meters or an enclosed kettle system where a weighed amount of various liquids are pressurized and transported to the nozzle system designed for the flow of each liquid. Metered stream of dry kibble can enter system using rotary disc technology. Kibble flows over a cone spreading it thinner in a 360-degree circles while the spinning disc is sprayed with liquids and is slinged out onto the kibbles. Another method incorporates a nebuliser head where the liquids are atomized as the kibble is fogged while passing through this system. Many combinations of the above system exist such as cut and fold conveyors system single or double shafted with counter rotating designs. Vacuum coating systems are finding use in pet foods again due to the diversity and requirements in today’s pet foods which included daily diets which might include exacting levels of some ingredients for all the possible situations in our pets. The key is using a system that yields accuracy you can live with.
Evaluate the investment cost with the possible savings by testing your existing system and also testing the future possibilities to determine a payback time. It would not surprise me in many cases where upwards of 500,000 to 1,00,000 dollars a year could be saved from over application of these expensive ingredients.
Published in the March 2024 issue of International Pet Food.
