Bioactive amines and internal quality of commercial eggs

Abstract

The physicochemical and microbiological qualities of commercial eggs produced by layer hens of different ages (approximately 30 and 60 wk old) were submitted to storage under room temperature or refrigeration for 28 d. A total of 600 eggs were subjected to microbiological analyses of their inner contents and another 600 to a determination of Haugh units (HU) and bioactive amine content. A decrease in the quality of the inner contents of the eggs was observed during the experiment, mainly in the eggs from the 60-wk-old layers, which presented the worst HU values when stored at room temperature (P < 0.05). Microbiological analyses showed an absence of Salmonella spp., Staphylococcus aureus, and coliforms, either total or thermal-tolerant; however, low counts of other Staphylococcus species, Enterobacter spp., Pseudomonas spp., mesophilic aerobic bacteria, and fungi were also recorded. The chromatographic analysis of bioactive amines detected the presence of phenylethylamine in all albumens (38.0 mg/kg) and spermidine in the yolks (1.02 mg/kg). It was concluded that the age of the hens and the time and temperature of storage influenced the quality parameters of the eggs (P < 0.05). Furthermore, despite the low levels of microbial contamination found, phenylethylamine was detected in the albumen. It was not possible to establish index of quality of eggs using bioactive amines present in the yolk and albumen of eggs.