<b>Antagonistic activity of dairy lactobacilli against gram-foodborne pathogens</b> - doi: 10.4025/actascitechnol.v36i1.18776

Abstract

ABSTRACT. Thirty-five strains of lactic acid bacteria were isolated from artisanal raw milk cheese, presumptively identified and tested against one dairy Escherichia coli strain. Six lactobacilli, exhibiting antagonistic activity, were identified at the species level and their action was evaluated against four strains of Gram-foodborne pathogens (Escherichia coli O26, Escherichia coli O157:H7, Salmonella spp. 1023, and Salmonella Typhimurium) and the control strain Escherichia coli ATCC 45922. The antagonistic activity was determined by spot method and the inhibition zones were measured by Autodesk AutoCAD 2007. Three strains, all Lactobacillus paracasei, were active against all the pathogens; the other strains, all Lactobacillus plantarum, showed antagonistic activity against some pathogens. This study highlights the intense and different antagonistic activity induced by lactobacilli against various foodborne pathogens thus demonstrating that using selected lactic acid bacteria strains as adjunct cultures could be an effective strategy to prevent the development of foodborne pathogens in artisanal raw milk cheeses, and thus improving their safety.Keywords: food safety, lactic acid bacteria, raw milk cheese.Atividade antagônica dos lactobacilos lácteos contra bactérias patógenas Gramtransmitidas por alimentos RESUMO. Trinta e cinco cepas de bactérias lácticas foram isoladas de queijo artesanal de leite cru, presuntivamente identificados e testados contra um coe láctico de Escherichia coli. Seis lactobacilos, exibindo atividade antagônica, foram identificados ao nível da espécie e sua ação foi avaliada contra quatro cepas de bactérias patógenos Gram-transmitidas por alimentos (Escherichia coli O26, Escherichia coli O157:H7, Salmonella spp. 1023 e Salmonella Typhimurium) e a coe de controlo Escherichia coli ATCC 45922. A actividade antagonista foi determinada pelo método de mancha e as zonas de inibição foram medidos por Autodesk AutoCAD 2007. Três cepas, todos Lactobacillus paracasei, foram ativos contra todas as patógenos; as outras cepas, todas Lactobacillus plantarum, apresentaram atividade antagônica contra alguns patógenos. Este estudo destaca a intensa e diferente atividade antagônica induzida por lactobacilos contra vários agentes patogénicos de origem alimentar. Isto demonstra que o uso de cepas de bactérias lácticas seleccionadas, como culturas adjuntas pode ser de grande ajuda e representa uma estratégia eficaz para evitar o desenvolvimento de agentes patogénicos de origem alimentar em queijos artesanais de leite cru, de modo a melhorar a sua segurança.Palavras-chave: segurança alimentar, bactérias produtoras de ácido láctico, queijo de leite cru.

Influence of probiotic (Lactobacillus acidophilusNCFM,L. paracaseiLPC37, andL. rhamnosusHN001) strains on starter cultures and secondary microflora in Swiss- and Dutch-type cheeses

“…acidophilus 4962 reduced the levels of E. coli O157:H7 populations in white cheese. On the other hand the L. paracasei and L. plantarum isolated from artisanal raw milk cheese reduced the levels of Escherichia coli O26, Escherichia coli O157:H7, and Escherichia coli ATCC 45922 (Geria, Dambrosio, Normanno, Lorusso, & Caridi, ). The average counts of yeasts and molds in control Swiss‐type and Dutch‐type cheeses were determined at 2.88 and 3.00 log CFU g −1 , respectively, and they were lower than that reported by other authors (Darehabi & Nikmaram, ).…”

Selenium Nanoparticle-Enriched and Potential Probiotic, Lactiplantibacillus plantarum S14 Strain, a Diet Supplement Beneficial for Rainbow Trout

“…Isolates were individually screened to detect their antibacterial activity against indicator bacteria. Indicator bacteria included both Gram-positive ( Staphylococcus aureus ATCC 25923 and Bacillus subtilis ATCC 6633 strains) and Gram-negative bacteria ( Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 10145 strains) and were tested according to Schillinger & Lücke [ 56 ] and Geria et al [ 57 ] with modifications. Briefly, each LAB strain, adjusted to 0.5 McFarland, was individually sown by swabbing on Petri dishes containing a thin layer of MRS agar and then 4 mm in diameter discs were aseptically removed.…”