In vitro assessment of the probiotic potential of lactobacilli isolated from Minas artisanal cheese produced in the Araxá region, Minas Gerais state, Brazil

ABSTRACT Minas artisanal cheese is made from endogenous starter cultures, including lactic acid bacteria (LAB). Some LAB may possess probiotic potential. Thus, this study aimed to evaluate the in vitro probiotic properties of lactobacilli isolated from Minas artisanal cheeses produced in Minas Gerais. Ten samples of lactobacilli, formerly isolated from those cheeses, were submitted to the following assays: antimicrobial susceptibility, tolerance to artificial gastric juice and biliary salts, production of hydrogen peroxide and antagonism against pathogenic and non-pathogenic micro-organisms. Only L. plantarum (C0) was sensitive to all tested antimicrobials, while the other LAB samples were resistant to at least one drug. Six samples were tolerant to artificial gastric juice, and L. brevis (A6) even grew in that medium. Three samples were tolerant to biliary salts. Only L. brevis (E35) produced hydrogen peroxide. Difference (P< 0.05) was observed among the means of inhibition haloes of lactobacilli against Enterococcus faecalis ATCC 19433 and Lactobacillus plantarum C24 in spot-on-the-lawn assay. All samples of lactobacilli inhibited Escherichia coli ATCC 25922, Salmonella enterica var. Typhimurium ATCC 14028 in co-culture antagonism test (P< 0.0001). Most lactobacilli samples showed in vitro probiotic potential. From the tested samples, L. brevis (A6) presented the best results considering all in vitro probiotic tests.

摘要：米纳斯手工奶酪（Minas artisanal cheese）是以包括乳酸菌（lactic acid bacteria, LAB）在内的内源发酵剂制备而成。部分乳酸菌具备益生潜能。因此，本研究旨在评估分离自米纳斯吉拉斯州生产的米纳斯手工奶酪中的乳杆菌的体外益生特性。本研究选取10株此前从上述奶酪中分离得到的乳杆菌菌株，开展以下试验：药敏敏感性试验、人工胃液与胆汁盐耐受性试验、过氧化氢生成试验，以及对病原与非病原微生物的拮抗试验。仅植物乳杆菌（L. plantarum, C0）对所有受试抗菌药物敏感，其余乳杆菌菌株均对至少一种药物耐药。其中6株菌株可耐受人工胃液，短乳杆菌（L. brevis, A6）甚至可在该培养基中生长。3株菌株可耐受胆汁盐。仅短乳杆菌（E35）可产生过氧化氢。平板点种试验（spot-on-the-lawn assay）结果显示，各乳杆菌菌株对粪肠球菌（Enterococcus faecalis ATCC 19433）与植物乳杆菌C24的抑菌圈直径均值存在显著差异（P<0.05）。共培养拮抗试验中，所有乳杆菌菌株均可抑制大肠杆菌（Escherichia coli ATCC 25922）与肠炎沙门氏菌鼠伤寒亚种（Salmonella enterica var. Typhimurium ATCC 14028）的生长（P<0.0001）。多数受试乳杆菌菌株展现出体外益生潜能。在所有受试菌株中，短乳杆菌（A6）在各项体外益生试验中均表现最优。