Bacterial contamination of stored table eggs from commercial chickens fed garlic meal additive
Table eggs from poultry farms sometimes take weeks before consumption during which period they are either in-transit to consumers or are stored until purchased. Microbial contamination during this period being the cause of spoilage, determines the shelf-life of eggs. Garlic is known to possess antimicrobial activities. Its potential at improving the shelf-life of table eggs was investigated.
Three hundred and fifty-one Isa Brown pullets separated into four groups A, B, C and D of 90, 81, 90 and 90 birds, were placed on garlic-meal feed additive at 0.125%, 0.25%, 0.5% and 0%, respectively. At 53 week-old, sixty eggs/group were kept at room temperature (26-27.5oC), from which 8 eggs/group were selected on the day of lay and weekly for 4 weeks. One ml of vortex mixed albumin and yolk pooled from 4 eggs was diluted 1:10, inoculated on Plate Count Agar-PCA, Salmonella-Shigella Agar-SSA, Eosin-Methylene Blue Agar-EMBA and Saborand Dextrose Agar-SDA by pour plate method in duplicates and incubated at 36oC for 72 hours. Discrete colonies were sub-cultured in Nutrient agar and identified using cellular morphology and biochemical characteristics.
Bacterial growths were observed in groups A, C and D (75, 0 and 0 cfu/ml in EMBA, 100, 125 and 225 cfu/ml in PCA and 0, 25 and 25 cfu/ml in SSA, respectively, at 2 weeks of storage. At 3 weeks, all groups had bacterial growth except B, while at 4 weeks, all groups had bacterial growth with B having a load of 25.5 cfu/ml on PCA only. Escherichia coli, Enterobacter cloacae, Klebsiella pneumonia, Stenotrophomonas maltophilia and Citrobacter amalonaticus were isolated. Garlic-meal in feed of chicken layers at 0.25% delayed bacterial egg contamination, thereby prolonging the shelf-life and reducing the possibility of food poisoning in consumers, as well as, egg wastage with associated economic loss.
Keywords: Bacterial contamination, commercial chicken layers, garlic meal, table eggs, shelf-life