Bacterial contamination of stored table eggs from commercial chickens fed garlic meal additive

Abstract

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 (26-27.5^oC), 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 36^oC 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