The behaviour of Enterobacteriaceae in Manchego cheese made from raw ewes' milk treated with hydrogen peroxide, potassium nitrate or potassium nitrite

Growth of Enterobacteriaceae, coliforms and faecal coliforms in Manchego cheese during the first 24 h after manufacture was retarded by treatment of milk with 0.1 g 1^-1 H₂O₂ compared to growth in control cheese made from untreated milk. Moreover, the decrease in their numbers during cheese ripening was accelerated by the H₂O₂ treatment of milk. In contrast, KNO₃ or KNO₂ addition to milk enhanced the growth of these micro-organisms during cheese manufacture and favoured their survival during ripening.