Abstract

The salt curing process may cause contamination of skin with micro-organisms found in the salt. Moderately halophilic bacteria are among the dominant halophilic micro-organisms which adversely affect skin quality. Therefore, the study was focused to examine prevalence and total numbers of aerobic bacteria, moderately halophilic bacteria, proteolytic and lipolytic moderately halophilic bacteria in curing salt samples and examine colony characteristics and biochemical reactions of moderately halophilic bacteria. Twenty-five salt samples that are used in the preservation of hides and skins were collected from different leather factories in Corlu (20 salt samples) and Tuzla (5 salt samples) Leather Organized Industrial Zones in Turkey. The pH, ash and moisture values of the salt samples were respectively determined as between 6.60-7.95, 90%-96%, 2.1%-2.9%. The total numbers of aerobic bacteria, moderately halophilic bacteria, proteolytic and lipolytic moderately halophilic bacteria in the samples were detected as 2-70 CFU/g, 1-13 CFU/g, 1-13 CFU/g and 1-4 CFU/g, respectively. Ninetyfive moderately halophilic bacterial isolates were recovered from the salt samples. Three, thirteen, seventeen, fifty-six, two, four, five percent of the bacterial colonies were dark yellow, pink, white, cream, beige, dark cream and yellow, respectively. Seventy-nine, sixteen, four and one percent of the bacterial colonies were found as circular, punctiform, irregular and rhizoid, respectively. Sixty-six, thirty-four, forty-five and fifty-five percent of the isolates were Gram-positive, Gram-negative, coccishaped, and rod-shaped cells. Fifty-four and thirty-eight percent of the isolates were motile and endospore-forming bacteria, respectively. All isolates grew on complex agar media containing 3-15% NaCl (w/v) concentration but did not grow on complex agar medium without NaCl and complex agar medium with 30% NaCl. While optimal growth of eighty-two percent of the isolates were observed at Complex agar medium with 10% NaCl, eighteen percent of isolates exhibited optimal growth at Complex agar medium with 10-15% NaCl. All isolates were catalase-positive. Sixty-one, seventy-four, twenty-five, sixty percent of the isolates produced oxidase, protease, lipase, and amylase enzymes, respectively. Thirty-three of percent of the isolates produced ammonia from peptone. In conclusion, all salt samples contained moderately halophilic bacteria, 92% and 48% of salt samples comprised respectively proteolytic and lipolytic moderately halophilic bacteria. Therefore, destructive moderately halophilic bacteria in each salt should be removed using antimicrobial applications before curing process to prevent damage to the salted hides and skins during storage.