Vitamin D. UHT. Grade A. Shelf stable. The Grossner Family has been producing quality dairy products for over 50 years. Gossner milk is easily stored at room temperature. Remember, however, once the package is opened it should be used or refrigerated just like any other milk. Gossner milk is a perfect choice for many occasions: breakfast, hiking, camping. school lunch, travel, food storage. Gossner Foods Grade A Milk is ultra high temperature (UHT) processed to stay fresh with or without refrigeration until you are ready to use it. No preservatives are added.