Viability of commercial probiotic cultures (L. acidophilus, Bifidobacterium sp., L. casei, L. paracasei and L. rhamnosus) in cheddar cheese

Six batches of cheddar cheese were manufactured containing different combinations of commercially available probiotic cultures from three suppliers. Duplicate cheeses contained the organisms of each supplier, a Bifidobacterium spp. (each supplier), a Lactobacillus acidophilus (2 suppliers), and either Lactobacillus casei, Lactobacillus paracasei, or Lactobacillus rhamnosus. Using selective media, the different strains were assessed for viability during cheddar cheese maturation over 32 weeks. The Bifidobacterium sp. remained at high numbers with the three strains being present in cheese at 4 × 107, 1.4 × 108, and 5 × 108 CFU/g after 32 weeks. Similarly the L. casei (2 × 107 CFU/g), L. paracasei (1.6 × 107 CFU/g), and L. rhamnosus (9 × 108 CFU/g) strains survived well; however, the L. acidophilus strains performed poorly with both decreasing in a similar manner to be present at 3.6 × 103 CFU/g and 4.9 × 103 CFU/g after 32 weeks. This study indicates that cheddar cheese is a good vehicle for a variety of commercial probiotics but survival of L. acidophilus strains will need to be improved.