EFFECT OF TEMPERATURE AND LENGTH OF STORAGE ON pH OF INTERNAL CONTENTS FOR CHICKEN TABLE EGG IN HUMID TROPICS

Résumé

All foods have limited shelf life which will vary depending on the food and storage conditions. Eggs are perishable food and storage temperature is an important factor that affects the shelf life of table egg. In tropical countries like Nigeria, eggs are usually preserved under ambient condition due to erratic power supply, which reduces the efficiency of refrigeration system. The aim of the present study was to examine the effects of storage periods, temperature and their interaction on the pH of chicken egg internal properties (yolk, albumen and whole egg). Fresh chicken table eggs were randomly allotted to three treatments of storage temperatures; refrigerator (4°C + 2), laboratory (32'c + 4), and poultry store room (37°C + 4). Eggs were assigned to treatments in a 3 x 8 factorial design, and each treatment was replicated thrice. The pH was measured daily for each of the storage period in all treatments. Storage temperature and periods had significant effect on pH of measured parameters with no significant interaction. The pH values increased with storage temperature and period between treatments. The rate of pH increase is significantly higher in ambient as compared to refrigerator temperature. In this study, only the refrigerator storage has pH values within the range for fresh table eggs. At storage period above three weeks, pH values increased beyond the range for fresh egg. It is validated that storage temperature and period affected egg shelf life, the rate of freshness reduced with increased temperature, thus, storage beyond three weeks of ambient temperature is not advisable in humid tropics