Over 290 waste streams were identified by REFRESH researchers in a thorough review of expert knowledge, commercial literature, books, scientific papers and internet sources.  These were scored and reviewed to narrow down to a list of 37 priority waste streams for further study and evaluation. The resultant list includes well-known examples like spent grains and other organic waste streams from the production of alcoholic beverages (ales, lagers, cider, wines and spirits), press cakes from vegetable oil processing, and meat & dairy side-streams such as slaughter by-products and whey protein.  Fruits & vegetable waste streams, which are often considered to have lower environmental impacts, are represented by apple pomace, orange peel / juicing residues and tomato pomace.

The report provides clear focus to the REFRESH project regarding those waste streams across a range of food groups which are present in high volumes with high environmental impact. These waste streams – often used as animal feed - can be further studied and evaluated to see if these impacts can be reduced.