Presence of salmonella and some indicator microorganisms in shell eggs produced in different rearing systems

Aim: In this thesis, it is aimed to determine the presence of Salmonella and some indicator microorganisms in shell eggs produced different rearing systems and to detect the species distribution of Enterobacteriaceae bacteria.Materials and Methods: In this study, 350 chicken eggs produced with four different rearing systems [organic (n: 100), free-range (n: 100), cage-range (n: 50) and conventional (n: 100)] were investigated. It was analysed the presence of total mesophilic aerobic bacteria, total psychrotrophic aerobic bacteria, coliform, Escherichia coli, Enterobacteriaceae and Salmonella in eggshell surfaces, eggshells (pore) and egg yolks. In addition, the species distributions of Enterobacteriaceae isolates obtained from egg samples were investigated.Results: The mean count of total mesophilic aerobic bacteria, total psychrotrophic aerobic bacteria, coliform, Escherichia coli, Enterobacteriaceae on the eggshell surface was found to be 4,14±0,96, 3,70±0,96, 2,88±1,20, 1,86±0,86 and 1,92±0,83 log cfu/ml respectively; and in the eggshell (pores) was detected to be 2,71 ± 0,98, 2,55±1,22, 1,59±0,60, 1,28±0.41 and 2,02±0,80 log cfu/ml respectively. There was found to be significant difference between rearing system and count of TMAB, TPAB and E. coli on the surface of the eggshell (P<0,05). However, there was no significant difference was found to be between rearing system and count of coliform and Enterobacteriaceae on the surface of the eggshell (P>0,05). The species of Enterobacteriaceae isolated from the eggshell surface and eggshell (pores) were determined to belong to Escherichia, Serratia, Enterobacter and Raoultella genera. Salmonella was detected from only one eggshell (pores) pool but not neither eggshell surfaces nor egg yolks. Conclusion: In this thesis results showed that the shell eggs may be contaminated with microorganisms that pose a risk to both product's shelf life and public health as a independent of the rearing system. The effective implementation of international food safety systems such as HACCP and ISO 22000 from farm to table will be important in controlling, reducing or eliminating risks.