Effect of Water Activity, pH, and Lactic Acid Bacteria to Inhibit Escherichia coli during Chihuahua Cheese Manufacture

This study aimed to evaluate the effectiveness of pH control, water activity (Aw), and the addition of lactic acid bacteria (LAB) on the proliferation of Escherichia coli in the curd during the manufacturing of Chihuahua cheese. Milk proved to be an excellent culture medium for E. coli, allowing it to develop at concentrations up to 10(9) cfu/g. However, the presence of LAB, the pH control, Aw, and especially the use of the Cheddarization process during the Chihuahua cheese production proved to be important obstacles that inhibited the proliferation of E. coli under the conditions studied. Moreover, reducing the water activity of the curd as quickly as possible is presented as the most powerful tool to inhibit the development of E. coli during the Chihuahua cheese-making process.