Selection and spray drying of lactic acid bacteria with potential industrial application

Abstract

One hundred lactic acid bacteria from the Brazilian territory underwent thermal, osmotic, and oxidative stress analyses as a screening method. Subsequently, 15 selected strains underwent species-level identification analysis (MALDI-TOF). Of these, 14 underwent pathogenicity analyzes (DNase, gelatinase and hemolytic) and technological potential analyzes (proteolytic, lipolytic, amylolytic, fermentation of different carbohydrates, coagulation, acidification, production of diacetyl, exopolysaccharides and gas, survival in NaCl concentrations, simulated gastric and pancreatic environments). From these, 3 underwent antibacterial activity against 4 pathogens (Listeria monocytogenes ATCC 5779, Escherichia coli IAL1848, Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212) and antimicrobial susceptibility with 9 antibiotics (ampicillin, penicillin, streptomycin, gentamicin, erythromycin, tetracycline, vancomycin, chloramphenicol and cotrimoxazole). The 3 strains and a pool of them were spray dried, had the powders analyzed (water activity, scanning electron microscopy and moisture content) and were stored for 30 days at 35 °C ± 2 °C, 5 °C ± 2 °C and room temperature. The counts after 30 days were above 8 log CFU/mL for all bacteria and storage conditions. The bacteria showed no pathogenicity, were susceptible to at least 2 antibiotics (as recommended by ANVISA – Brazilian National Health Surveillance Agency), and inhibited the tested pathogens. They exhibit characteristics that resemble non-starter lactic acid bacteria (NSLAB) as adjunct cultures, and the results inspire carrying out additional tests to evaluate the probiotic features and technological applications in dairy industries.