Determination of Contamination of eggs in Ardabil city with Staphylococcus aureus, Bacillus cereus , Proteus mirabilis and Enterobacter aerogenes

Bacterial zoonotic diseases are one of the most important health problems in human societies which in this category, food-borne diseases are special importance. Contaminated Foods with animal origin such as eggs can one of the most important sources of disease transmission to human. Therefore, the purpose of this study was to investigate the contamination of eggs with gram-positive bacterial species of Bacillus cereus and Staphylococcus aureus and gram-negative of Proteus mirabilis and Enterobacter aerogenes in Ardabil city. A total of 240 eggs (80 native eggs, 80 bulk eggs and 80 labeled industrial eggs) were collected randomly from retail stores in different parts of Ardabil a period of six months during 2019 and 2020 and transferred to the laboratory under sterile conditions. Shell and contents of the eggs were examined for bacterial contamination by standard culture methods, Gram Staining and Oxidase and Catalase tests. Out of 240 samples examined, 14 samples (5.83% ) bacterial contamination were identified. The highest contamination was observed in native eggs (57.14%), bulk eggs (35.72%) and labeled eggs (7.14%), respectively. Bacterial contamination in the shell of native, bulk and labeled eggs were 7.50%, 5.00% and 1.25%, respectively, and in the contents of native and bulk eggs were 2.50% and 1.50%, respectively. No bacteria were isolated from the contents of labeled eggs. There was no contamination by Proteus spp and Enterobacter spp among the samples examined, however, 33.3% of the samples were contaminated by Staphylococcus spp and 2.50% of the samples by Bacillus spp. The results of this study indicate the presence of contamination of Staphylococcus spp and Bacillus spp in eggs especially native eggs in Ardabil region which can lead to bacterial zoonotic diseases in human if eggs are consumed unhygienically.