Phenotypic and genotypic characterization of non-starter Lactobacillus species diversity in Indian Cheddar cheese

- Cheddar cheeses of Indian origin made from cow milk and mixed milk were compared.
- Different manufacturing parameters were followed in the cheese collection plants.
- Partial tuf gene sequences were able to resolve species showing ambiguous biochemical profiles.
- Lactobacillus coryniformis & Lactobacillus delbrueckii species reported first time.
- Novel L. delbrueckii isolates obtained.

A total of 243 non-starter lactobacilli were isolated from 12 premium quality Indian Cheddar cheese samples ripened for different periods and in different plant conditions. They were classified up to species level using mainly sugar fermentation assay and PCR. Based upon phenotypes, a maximum of 46.50% were classified as Lactobacillus paracasei, followed by 34.98% isolates as Lactobacillus plantarum. Only 3.29% were classified as Lactobacillus rhamnosus and 4.12% as Lactobacillus delbrueckii species, while 22 (9.05%) isolates (of which 16 L. plantarum/Lactobacillus paraplantarum and 6 Lactobacillus delbrueckii ssp. lactis/Lactobacillus crispatus) could not be designated to a single species. One isolate of Lactobacillus coryniformis ssp. coryniformis was isolated for the first time from Cheddar cheese (0.41%) while 1.65% isolates remained unidentified. Mostly, the tentative characterization based on phenotype, could be confirmed by PCR targeting rRNA. Those isolate groups which could not be tested in PCR, or resembled with more than one species in their phenotypic traits, could be resolved by the BLAST homology analysis of the partial tuf gene sequences of few representative isolates.