This paper should be cited as:Dorri K, Namdar N, Hemayat khah Jahromi V

Isolation of Lactobacilli from Dairy Products and Their Effects on the Main Pathogenic Bacteria in Stomach and Intestine

Dorri, K. (MSc)*1, Namdar, N. (MSc)2, Hemayat khah Jahromi, V.(PhD)3

1. MSc of Biology, Department of Microbiology, Jahrom Branch, Islamic Azad University, Jahrom, Iran

2.MSc of Biology, Department of Microbiology, Jahrom Branch, Islamic Azad University, Jahrom, Iran

3. Assistant Professor, Department of Biology, Jahrom Branch, Islamic Azad University, Jahrom, Iran

Background and objective: The effects of lactobacillus Species (and their supernatants) in dairy products were proved as probiotics on pathogenic bacteria. The aim of this study was to isolate the lactobacillus from dairy product (Yogurt, cheese, milk and whey …) and to determine the antimicrobial activity against some pathogenic bacteria (Salmonella typhimurium, E.coli, Helicobacter pylori

Material and methods: Samples of dairy products were collected and were serially diluted in peptone medium. To isolate lactobacillus, diluted sample were plated on to MRS Agar medium and incubated at 37^ºc for 48-72h in anaerobic condition. Identification of the lactobacilli was performed according to their morphological, cultural, physiological and biochemical characteristics. The inhibitory effect of isolated lactobacillus strains were performed against pathogenic bacteria by Agar well diffusion assay and disc method.

Results: of 50 samples of isolated Lactobacillus from dairy products (including 11 identified Lactobacillus), 19 samples have inhibitory effect on pathogenic bacteria such as Salmonella typhimurium, Escherichia coli and Helicobacter pylori0. The most identified strains areLactobacillus bulgaris, Lactobacillus Salivarius and Lactobacillus delbrueki.

Conclusion: According to this study, some lactobacillus strains isolated from dairy products are useful in the management of diarrhea and other gastrointestinal disease s and the use of these strains can be useful for prevention and treatment.

Keywords: Lactobacillus,Dairy products,SalmonellaTyphimurium, E.coli, Helicobacter pylori

Corresponding Author: Dorri K

Email: s.dorri@gia.ac.ir

Received 4 Aug 2012Revised 5 Dec 2012Accepted 2 Jan 2013