Antimicrobial Activity , Antibiotic susceptibility and Aflatoxin B1 Reducion potential of Lactobacillus spp Isolate From Traditional Dairy Products against food-borne pathogens

Publish Year: 1397
نوع سند: مقاله کنفرانسی
زبان: English
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NCFOODI25_015

تاریخ نمایه سازی: 26 خرداد 1398

Abstract:

Microorganisms plays very important role in food industry. One of the most important groups of acid producing bacteria in food industry is the lactic acid bacteria.Genus Lactobacillus contains over 110 species,which are classified in three major groups:obligate homofermentative,facultative homofermentative and obligate heterofermentative.The Lactobacilli isolated from dairy products have shown a long history of safe use.the main aim of this study was Isolation,characterization of Lactobacillus spp isolated from the traditional dairy products and determination of probiotic potential,Antimicrobial acyivity against food-borne pathogens including salmonella,E.coli,shigella,Bacillus Cereus, staphylococcus areus (ATCC and previously isolated in our division),antibiotic susceptibility and Aflatoxin B1 detoxification potential .A total of 40 traditional dairy products including household milk , cheese , yoghurt and curd were collected from local areas of Azerbaijan , Kurdistan , kermanshah , ilam in Iran.Isolation was done by using serial dilution method.Serial dilutions of dairy samples were prepared and then sample from different dilutions were spread over the solidified MRS medium for isolation. Plates incubated under anaerobic condition at 370C for 24-48hrs. After incubation isolated colonies were restreaked on MRS agar plate and pure cultures were isolated.Three to four colonies of each culture were selected for further characterization. Identification of Lactobacillus isolates was performed by biochemical [Gram stain , catalase, fermentation of carbohydrates, hydrolysis of arginine, gas (CO2) production from glucose and growth at different temperatures(15°C, 45°C)] and 16S rRNA gene sequencing methods and assessed for probiotic potential properties including acid and bile resistance , Adherence to HT-29 cells and antibiotic resistance .An agar well diffusion assay was used for detection of antimicrobial activity of lactobacillus isolates against food-borne pathogens. Etest , Disk diffusion and Broth microdilution used for Antibiotic susceptibility . The toxification of aflatoxin by lactobacill spp isolate was quantified by Elisa method . Statistical analyses were performed with SPSS software (version16.0, SPSS). One-way ANOVA (Analysis Of Variance) with post-hoc Tukey HSD (Honestly Significant Difference) was used for statistical analysis.Results were regarded as statistically significant at p< 0.05.We identified Six species of Lactobacillus (Casei , plantarum ,acidophilus , delbrueckii, fermentum,brevis). All Isolate showed good probiotic potential and Lb. fermentum showed adherence specificity to HT-29 cells and Lb. acidophilus showed good acid and bile Tolerance.Lb.brevis and Lb acidophilus exhibited the capability of reducing the amount of aflatoxin B1 .the majority of the strains exhibited antagonistic activity food-borne pathogens including salmonella , shigella , E.coli , Bacillus Cereus , staphylococcus areus respectively. Lactobacillus Casei showed the most antibacterial activity against tested food-borne pathogens and showed the highest inhibitory against salmonella , shigella and lowest inhibitory against Bacillus Cereus , staphylococcus areus .Antobiogram test showed that the isolate was sensitive to Florfenicol , Erythromycin , Amoxycilin , Lincospectin ,Penicilin and moderately sensitive to Gentamycin , Sultrim.All isolates were resistanst to streptomycine , Ciprofloxacin , Enrofloxacin , Fosbac , Doxycline, Tetracycline . the isolates except four isolates were resistanst to vancomycine.this study showed that Lactobacillus strains with good probiotic potential could be isolated from traditional dairy products.Some Lactobacillus strains have Aflatoxin detoxification potential .1- M.Sc. Bacteriology2- Assistant Professor.Microbiologysuch isolates could be used in food and feed industries to detoxify the aflatoxin B1 . all isolates have antibacterial effect against food-borne pathogens and lactobacillus Casei showed the most antibacterial activity against tested food-borne pathogens thus researcher suggest Lactobacillus isolated from traditional foods use as natural preservatives in food stuffs and the bacteriocines could be useful for production of antibacterial agent in food stuffs and suggests a new approach for biocontrol of food borne pathogens but further in vitro and in vivo studies on these strains are still required.

Authors

H Alizadeh

Rooyana Laboratory , saghez , kurdestan , Iran

A Amini fazl

Assistant Professor,Microbiology ,Department of veterinary, Islamic Azad university , Mahabad branch , Iran