Med. Weter. 71 (5), 303-306, 2015

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Drozd Ł., Gondek M., Szkucik K., Knaga S., Ziomek M.
Microbiological contamination of quail eggshell surfaces
The aim of the study was to establish the variation in microbial contamination of quail eggshell surfaces depending on the frequency of hygiene-sanitary practices carried out in cages (washing, disinfection and fecal waste removal). The studies involved eggs collected from three quail breeding farms situated in south-eastern Poland and characterized with different frequencies of hygiene practices. From October to April, 50 eggs were collected from each farm at five different collection times, at 3-week intervals. The freshly laid eggs were collected in a sterile way directly from the cages, cooled and transported to the laboratory to be subjected to a rinsing treatment with a sterile solution technique to obtain 10-1/cm2 dilution of the eggshell surface. The obtained study material was evaluated for a total count of aerobic bacteria, numbers of proteolytic bacteria and bacteria from the Staphylococcus genus, counts of aerobic bacteria and microorganisms from the Enterobacteriaceae family, as well as the number of yeasts and moulds. As per entire egg surface, the presence of pathogenic microorganisms from the Salmonella, Campylobacter and Listeria genus were detected. The determinations were performed in accordance to Polish Standards. Relatively slight contamination of eggshell surfaces was established (from 4.7 x 102 ¬up to 4.7 x 103 cfu/cm2), and its contamination level varied between the farms. Out of the microbial groups under study, Staphylococcus spp. constituted the predominant part of microbial flora (32.7 % - 51.5 %), yet only a single sample was found to harbor coagulase-positive staphylococci (Staphylococcus aureus subsp. anaerobius). The presence of neither moulds nor yeasts was confirmed on the shell of eggs collected from farm 1, while their counts on the eggs obtained from two other farms did not differ significantly and ranged between 0.8 x 102 and 1.2 x 102. In two samples, microorganisms from the Listeria genus were recovered; however, the PCR studies did not confirm their belonging to the L. monocytogenes species. The presence of Campylobacter and Salmonella genus bacteria on the eggshells under study was not detected. It was found that frequency of hygiene-sanitary practices carried out at a farm had a significant effect on the level of microbial contamination of quail eggshell surfaces. The cleaning of cages (washing and disinfection) together with daily removal of feces considerably reduced microbial contamination of eggshells. The absence of bacterial pathogens of Campylobacter and Salmonella genus and L. monocytogenes on the studied eggshell surfaces and a low level of total microbial contamination indicate that quail eggs are safe for consumers on condition that sanitary regulations are observed.
Key words: egg, quail, microbial contamination, pathogens