Gıda Tuzlarında Halotolerant Bakterilerin İncelenmesi

Abstract

Twenty-five food salts, collected from seven-country, were examined for moisture contents and ash contents, pH values, total numbers of bacteria, and total numbers of bacteria halotolerant bacteria. The growth and biochemical reactions of halotolerant bacteria at different NaCl concentrations, pH, and temperature values were investigated. The efficacy of dry-heat sterilization and high-pressure steam sterilization for the inactivation of bacteria was examined using six food salts. Moisture contents, ash contents, and pH values of salts were respectively found as 2.3-3.7%, 95-97%, and 6.37-9.94. Total numbers of bacteria and halotolerant bacteria were detected as between 1-58 CFU/g and 1-40 CFU/g on Modified Nutrient Agar media, respectively. While bacteria were found in twenty salt samples, halotolerant bacteria were detected in seventeen samples. One hundred thirty- eight rod-shaped halotolerant bacteria were isolated from seventeen samples. One hundred eighteen and twenty isolates were found Gram-positive and Gram-negative, respectively. While 131 isolates were motile, seven isolates were observed as non-motile. All isolates grew in both absence of NaCl and presence of 10% NaCl, pH 5, 7, and 9, 24°C, and 37°C. Eighty-six isolates showed different pigmentations. Ammonia production was detected at sixty isolates. Catalase, oxidase, protease, lipase, amylase, caseinase were produced by 138, 83, 84, 48, 92, 100 isolates, respectively. Fifty-seven percent of halotolerant bacteria formed endospores. All bacteria in six salts were killed using both dry-heat sterilization (175oC for 2 hours) and high-pressure steam sterilization (121oC for 30 minutes). In conclusion, we suggest using dry-heat sterilization or high-pressure steam sterilization to kill Gram-negative halotolerant bacteria containing endotoxin and Gram-positive halotolerant bacteria with endospores in food salts to prevent food spoilage and foodborne diseases in humans.