Assumptions often become the default truth. I recall an assumption that was accepted as truth by the community in my first employment. The assumption was that the dog food factory had to generate an awful smell.  I was appointed as the production manager and one of the products under my jurisdiction was canned pet food. The era was the mid nineteen seventies. The dog food manufacturing process involved preparing ingredients (meat byproducts and grains), mixing and cooking the ingredients, pumping the mix to a filling machine which filled cans at high speeds.  These cans were seamed and then sterilized in large, high temperature retorts (pressurized vessel used for thermal sterilization) for seventy minutes. 

Most of the staff, including me, found the smell in the factory loathsome; it permeated the clothing of all who worked there. In addition, when the finished canned product was opened the content would pour out like a thick slop and had a distinctly unpleasant smell.  The assumptions that needed challenging were that dog food factories needed to emit unpleasant odours and that canned dog food has a runny texture accompanied by an unpleasant smell. I had become aware of these assumptions but fortunately I was new to the job and was not invested in them. My main driver was to eliminate the awful smell in the factory. I certainly could not entertain any visitors at work and needed a very long shower after a day at work. 

Experiment – use trial and error

Despite the assumptions inherent in the canned dog food industry my senior manager and I decided to experiment in an attempt to eliminate the foul smell in the factory.  I mixed a batch of ingredients but did not boil the mix. It was clear that boiling the mix generated the smell in the factory. My hope was that the boiling may not be needed as the can could act as its own miniature cooking pot once it was filled and sealed. The seventy minute sterilization would then serve the dual process of cooking and sterilizing the content. This simple experiment in cold filling succeeded in eliminating the odour in the factory and had two additional benefits. The texture of the dog food improved. It had the characteristics of a meatloaf as opposed to slop. This was due to the meat proteins binding together and forming a loaf like product whilst being heated in the can. The existing method of precooking and mixing during the cooking process broke down the binding properties of the meat proteins before they were filled into cans. You could liken this to the producing a meatball texture as opposed to a mincemeat or stew texture. The most surprising benefit from the cold fill experiment was that the end product also had a much better and acceptable smell. 

The only (huge) problem was that all the cans had distorted during the high pressure sterilization process and could not be used for labeling and selling. My research and development colleagues informed me that filling with frozen meat ingredients, or so called “cold filling” was not feasible as the cans would always distort. They added that the product needed to be hot filled as part of the canning process. They explained that even canned fruit used hot syrup to facilitate the canning process.  

It took a few months of trial and error experimentation and many wasted cans to work out how to cold fill pet food cans without distorting the cans. The answer lay in the use of sufficient headspace and an injection of steam immediately before closing and seaming. This created a vacuum in the head space of the can that eliminated the problem of the cans distorting. Canned pet food would never be the same. If you were around, I wonder if you remember opening a can of pet food pre nineteen seventy five. 

Challenge your assumptions, experiment – use trial and error

Dr Steve Harris – Mind Doctor