Purpose: To isolate, characterize and identify LAB from various food sources during spoilage.
Methods: Various foods (meat, poultry, seafood and produce) were stored either under refrigeration or room temperature till deemed spoiled. At specified intervals, samples were either swabbed (10 sq. cm) using a sterile swab or diluted in Buffered Peptone Water (BPW) (1:10), serially diluted (1:10 in BPW), spread plated on MRS agar and incubated anaerobically (30°C; 48 h). After incubation, typical LAB colonies were isolated and biochemically characterized (cell-wall type, catalase, oxidase, spore forming ability, acid-fast staining). Isolates exhibiting typical LAB biochemical characteristics were used to determine carbohydrate as well as protein substrate utilization patterns and identified using VITEK-2. Isolated were also grouped based on the substrate utilization patterns using cluster analysis.
Results: A total of 90 isolates were identified either as Leuconostoc spp., Lactococcus spp., Streptococcus spp., Pediococcus spp., or Enterococcus spp. Isolates exhibited varying levels of carbohydrate and protein utilization indicating diversity in the LAB.
Significance: Diversity in LAB can be further explored to determine their antimicrobial efficacies to improve food safety and increase shelf life.
Acknowledgements: BIG and C-CAMP, India