Microbiological quality of raw fish at retail market in Latvia

Abstract

The aim of the study was to evaluate the microbiological quality of raw fish obtained from retail market. Overall, 20 raw fish samples, including roach (Rutilus rutilus), crucian carp (Carassius carassius), European perch (Perca fluviatilis), silver bream (Blicca bjoerkna) and round gobby (Neogobius melanostomus) were collected during October, 2014. Samples were analyzed for total bacterial count, Enterobacteriaceae count, Escherichia coli, Listeria monocytogenes and Salmonella. Total bacterial count in raw fish ranged from 5.58 to 7.84 log10 CFU cm−2. Total bacterial count in silver bream (7.57 log10 CFU cm−2) were significantly higher (p<0.05) than in round gobby (6.31 log10 CFU cm−2). Enterobacteriaceae counts ranged from 1.91 to 5.28 log10 CFU cm−2, and there were no significant differences (p<0.05) between fish species. E. coli was detected in three of 20 fish samples analyzed and E. coli count ranged from 1.11 to 1.72 log10 CFU cm−2. Overall 11 from 20 fish samples tested were positive for L. monocytogenes. However, all the samples were negative for Salmonella. This study demonstrates that high total bacterial count and Enterobacteriaceae numbers were determined in raw fish samples, as well as raw fish at retail level can serve as the potential reservoirs of L. monocytogenes. Introduction Fish are a source of high quality animal protein, containing considerable quantities of valuable lipids, minerals and vitamins. It is assumed that freshwater fish products are healthy food for human nutrition [1]. On the contrary, fish nutrient composition and high moisture content allow the growth of a large range of microorganisms, which affect fish quality and safety rendering fish unacceptable for human consumption [2]. Microbiological quality of raw fish results from microbiological load of aquatic habitat, methods of capture, transportation, chilling and storage conditions [3],[4].Total bacterial count (TBC), E [...].