The use of food waste as animal feed could contribute to a more circular and sustainable food production. Feeding swill (consumption phase food waste) however, is historically associated with disease transmission to animals and humans. The aim of this paper is to review the microbial health hazards of feeding swill to farm animals, with a focus on pigs and poultry. First, the current European food waste legislation is described. In literature 60 articles describing the hazards of feeding swill to pigs and poultry were identified. Most of the articles focus on viruses, mainly at the level of animal feed and animal-based food products. Articles describing bacterial hazards and also information on the microbial hazards on the level of kitchen and table waste and food consumption level were lacking. Described management factors related to swill feeding are factors such as herd size, management practices and biosecurity. This study shows that feeding kitchen and food waste to pigs and poultry includes various microbial health hazards. Many microbial hazards in animal feed can be overcome by adequate (heat) treatments, good facilities and strict regulations. However, also other hazards, such as non-infectious pathogens, physical and chemical hazards need more insight.