Phillip Lancaster, PhD
Food waste accounts for greater than 40% of food production, and food waste disposed of in a landfill contributes to methane emissions. Solid waste in landfills, although not all food waste, accounts for 14% of U.S. greenhouse gas emissions, which is more than agriculture at 9%. Globally, food waste accounts for 6 to 8% of greenhouse gas emissions; about half of the 14% contributed by livestock. However, most food waste could be recycled for a higher purpose. According to the food recovery hierarchy, food waste uses in order from least to greatest benefit are landfill/incineration, composting, industrial uses, animal feed, and donate to food pantries. Thus, animal feed is the most beneficial use of food not fit for human consumption.
Food waste occurs at many places along the food supply chain – food not harvested, lost during handling/transporting, industrial processing and manufacturing, retail groceries and restaurants, and in the home. Unfortunately, food not harvested or lost during handling/transporting has little chance of being recycled. Food waste from industrial processing and manufacturing sector is already highly recycled with only 5% going to landfills, but 45% of food waste from the retail level and 97% from the consumer level are disposed of into landfills. Over all sectors, recycling into animal feed is the largest (57%) destination of food waste followed by disposal in landfills (28%). Recycling into animal feed reduces the amount disposed into landfills.
One major issue with the use of food waste as animal feed is the variation in nutrient content from batch to batch. The unique digestive system of ruminants allows them to effectively utilize these variable feedstuffs with lesser consequences in performance than monogastric animals. Additionally, ruminants can utilize the wide variety of food waste sources produced in the food supply chain. Even though all livestock sectors use food waste derived animal feed, cattle are a major user because of their unique digestive system and large quantity of feed consumed daily. Thus, cattle contribute significantly to the efficiency and sustainability of the food supply chain.