THE INFLUENCE OF HALOPHILIC BACTERIA ON THE FISH QUALITY AND SAFETY

Kristijan VELJANOVSKI, Dijana BLAZHEKOVIKJ - DIMOVSKA

Abstract

Salting, together with the process of drying and smoking, is one of the oldest ways of fish preserving. Salting acts on the development of microorganisms in such a way that the salt takes away the water, and consequently, growth arrest, sporulation, or death of the bacteria occurs. Salt concentration above 10% in fish meat slows down the development of most putrefactive and proteolytic microorganisms, including pathogenic species. Higher concentrations of salt have a bactericidal effect on bacteria and stop growth, while some species sporulate. Only a relatively small number of microorganisms, called halophiles, can grow on nutrient media with increased salt concentration. Microorganisms, according to salt sensitivity, are divided into halophile microorganisms, halotolerant microorganisms, and molds. Halophiles are those microorganisms that tolerate increased salt concentrations well and are divided into facultative halophiles that do not need salt for their development, and non-facultative halophiles that need salt for growth and reproduction, in concentrations of 2%. True halophiles, which include species of the genera Halobacter and Halococcus, can reproduce at salt concentrations of 15-25%. Moderate halophiles, including species from the families Bacillaceae and Vibrionaceae, as well as species from the genus Micrococcus, can grow at salt concentrations of 3-15%. Halotolerant species belonging to Micrococcaceae and Corynebacterium tolerate salt concentrations up to 5%. Halotolerant bacteria are bacteria from the genera Micrococcus, Pseudomonas, Leuconostoc, Vibrio, and Streptococcus. The most sensitive genus to salt is the genus Clostridium. Most halophile microorganisms are not pathogenic for humans, except for bacteria from the genera Vibrio, Salmonella, Bacillus, Pseudomonas, Staphylococcus, Clostridium, etc. Spoilage of food caused by halophile bacteria is manifested by a change in its organoleptic properties (color change, the appearance of mucus, and sometimes the appearance of foreign odors and gases). This paper aims to show the importance and species of halophile bacteria in the processing of food of animal origin, as well as the influence of halophile bacteria on the fish quality and safety.

Pages: 132 - 138