ABSTRACT
Probiotics are the health promoting viable microorganisms that exhibit a beneficial effect on the health of human being by improving the intestinal microbial balance. Probiotic bacteria may produce various compounds, which are inhibitory to the growth of pathogen, which include organic acids (lactic and acetic acids), bacteriocins, and reuterin. In the present study a total of 17 food samples were collected for isolation of lactic acid bacteria. A total of 26 isolates of lactic acid bacteria were purified and screened for their antimicrobial activity against seven human pathogenic MTCC strains counting three test fungal strains such as Aspergillus fumigatus, Aspergillus sp. and Candida albicans and four test bacterial strains (two Gram-negative namely Escherichia coli, Salmonella enterica ser. typhi and two Gram-positive Staphylococcus epidermidis and Bacillus amyloliquifaciens). Out of 26, eight isolates were considered for further analysis of probiotic potential whose antimicrobial activity was found to be good against maximum number of tested strains. The selected lactic acid bacteria exhibited excellent probiotic characteristics and thus can be used as a potential source of probiotic. Study affirms their use in the development of new pharmaceutical preparations and functional foods belonging to vegetables and fruits (as origin) as probiotics for the betterment of public health.
ABSTRACT
In the present study, a total of six extracts of two spices namely black pepper and turmeric in three solvents were evaluated for their antibacterial and antifungal activity. The antibacterial activity was measured by agar well diffusion method and antifungal activity by poisoned food technique. All the extracts showed antibacterial activity against all the test bacterial isolates. Aqueous extracts of black pepper did not exhibit antibacterial activity against B. subtilis. In aqueous extract, black pepper and turmeric showed good inhibitory activity against Staphylococcus aureus with zone of inhibition 25mm to 30mm and 26mm to 28mm respectively. In ethanolic extract, black pepper extract showed antibacterial activity against all test bacteria with zone of inhibition ranged between 15mm and 22mm while turmeric showed activity with zone of inhibition ranged between 13mm and 24mm. In methanolic extract, the diameter of zone of inhibition ranged between 12mm and 28mm in black pepper and 13mm and 22mm in turmeric. In case of antifungal activity, only turmeric ethanolic extract showed activity only against Rhizopus stolonifer and Mucor sp. with percent mycelial growth inhibition ranged between 25% and 30%. Based on this finding, these extracts may be an alternative to chemical preservatives and used as natural antimicrobial preservatives to reclaim the shelf-life of food.