Microbial quality of raw and ready to eat eggs from open markets and hawkers in Nigeria

Abstract

In Nigeria, the eggs sold to the public are exposed to high storage temperature, without any indication of best buy dates. There is therefore a need to evaluate the microbial quality of eggs sold to the public. Forty-five pieces of raw and 15 pieces of boiled eggs were randomly procured from 9 vendors, in three open markets and motor parks. Samples were divided into batches containing 15 eggs each. For the microbial load of shell, the sample making a batch was washed in water and rinse water serially diluted and plated. The egg content for each batch was pooled, serially diluted and plated. Other biochemical evaluation methods for microbial identification were performed. All the raw (shell and contents) samples were positive for microbial growth on the agar plates. Total viable count ranged from 1.5 x 10⁵ to 1.0 x 10⁸ CFU/ml and 5.3 x 10⁴ to 1.1 x 10⁷ CFU/ml for egg shell and content respectively. Enterobacteriaceae count ranged from 3.3 x 10⁵ to 1.0 x 10⁷ CFU/ml. Boiled egg shell had high Salmonella-Shigella 1.2 x 10⁷CFU/ml count. Isolates from the raw samples included: Proteus spp, Escherichia coli, Staphylococcus spp, Streptococcus spp, Pseudomonas aeruginosa, Salmonella spp, Aspergillus and Penicillium spp. Isolates from the RTE eggs were Enterococcus fecalis, Serratia spp, Salmonella spp, Shigella spp and Staphylococcusspp. Eggs are contaminated with diverse microorganisms, therefore consumption of raw egg should be discouraged. Street vendors or hawkers need to be educated on safe food handling techniques.

Keywords: Eggs, hawked, eggs, RTE, food-hazard