@Scott & Elmsley was correct! And, Weruva's customer support was speedy and helpful! Another reason to be a fan (besides the fact that they have a grey kitty on their packaging which was the original reason I choose them to try out!).
Here is the reply:
Thank you for your email to Weruva and loyal support of our products. We appreciate the inquiry and are glad you contacted us.
Please know what you are seeing is not uncommon and is organic material. From time to time through the retort process, some food will get “cooked” and appear darker or “burnt” on the walls of the pouch. When the product slides out of the pouch these pieces also come out. There is no cause for concern from a food safety standpoint. I’ve never heard them described as “pudding skin” but that is probably the most accurate description.
From a production standpoint, we do not add any preservatives to the food. Our foods still have a 3 year shelf life, (2 years for pouches) and this is accomplished through the cooking process. The ingredients are first cooked, and the cooked food along with other ingredients are then put into the can or pouch where they are hermetically sealed. The next step in the production is the retort process. Based upon the size of the can or pouch, the ingredients in the can or pouch, and the density of the ingredients, the can or pouch is heated at a certain time and temperature. This phase, performed on international human food standards, is one of the critical control steps that is heavily monitored. This process is the commercial sterilization process that is designed to kill all single cell organisms. This is what gives our food a minimum two year shelf life without adding preservatives.
Please let me know if you have any other questions. We are happy to help!