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.