Effect of the low-fat Cheddar cheese manufacturing process on the viability of Bifidobacterium animalis subsp. lactis, Lactobacillus rhamnosus, Lactobacillus paracasei/casei, and Lactobacillus plantarum isolates

• Coagulation and cooking steps decreased the populations of probiotics, especially bifidobacteria.
• During cheese ripening the populations of probiotics, especially bifidobacteria decreased.
• More bifidobacteria had to be added into the cheese milk to obtain the target population in cheese.

The impact of the Cheddar cheese manufacturing process on the viability of five new probiotic candidates was evaluated in this study. Decreases in pH, changes in proteolysis, and sugar and acid contents during ripening were also determined. The Bifidobacterium animalis subsp. lactis populations decreased after the cooking step, whereas the Lactobacillus plantarum, Lactobacillus paracasei/casei, and Lactobacillus rhamnosus populations gradually increased. Salting had no impact on bifidobacteria counts, whereas the growth of lactobacilli slowed but then started again during the curd-pressing step. The bifidobacteria counts in cheese decreased greatly after 14 days of ripening, whereas the lactobacilli counts stayed stable or increased. Bifidobacteria produced acetic acid during cheese production and, in smaller quantities, during ripening, whereas L. plantarum produced acetic acid only during cheese ripening. Some strains had higher viability and were therefore better candidates for use as probiotics in low-fat Cheddar cheese.