ASSESSMENT OF SHELF LIFE AND BACTERIAL LOAD OF VIABLE EGGS OBTAINED AT THE POINT OF LAY FROM ROOM AND REFRIGERATOR STORAGE TEMPERATURES

Abstract

It is well established that storing hatching eggs over a longer period of time affects its quality. The current study evaluated the impact of egg storage duration in-relation to two different temperature conditions (room and refrigerator) to determine the bacterial load and shelf life of viable eggs. One hundred and twenty eggs were used for this study, 60 were boiled and 60 were raw. Thirty of the boiled eggs were stored at room temperature and the other 30 eggs were kept in the refrigerator. Similarly, 30 raw eggs were each stored at room and optimal refrigeration temperatures for eggs (< 7 ^oC) respectively, while the egg weight, viability and sensory tests were performed daily on the eggs. However, the eggs kept in the refrigerator were viable for longer and relatively maintained higher physical appearance and sensory quality compared to eggs kept at room temperature. In the investigation of bacterial load, the total viable count ranged from 6.0× 10³ to 11.9 × 10³ coliform forming unit per millilitre (cfu/ml) and 1.0 × 10³ to 6.5 × 10³ cfu/ml for the boiled eggs kept at room and refrigeration temperatures (BRT and BFT) respectively. More so, the bacterial counts in raw eggs obtained at room and refrigerator storage ranged from 4.8 × 10³ to 6.5 × 10³ cfu/ml. Subsequently, the characterization and identification of bacterial isolates indicated the presence of Salmonella pullorum, Proteus mirabilis and Pseudomonas sp. The Salmonella pullorum was isolated from all the egg samples (BRT, BFT, RRT and RFT). The Proteus mirabilis was isolated from boiled eggs kept in both room and refrigerator temperatures (BRT and BFT) while Pseudomonas sp. was obtained only from raw eggs stored in the refrigerator (RFT). In addition, the boiled eggs at room temperature started deterioration on Day 9, while its counterpart in the refrigerator began spoilage or decrease in quality from Day 16. The weight of the viable eggs in relation to the non-viable ones was statistically significant (P < 0.05). The refrigeration of eggs increases its longevity while proper hygiene and adequate boiling of eggs reduces the risk of acquiring infections through bacterial contamination.