Detection of Spoiled Eggs Using Different Techniques / Methods

Abstract

Egg is a nutritionally complete but highly perishable food, and in developing-country supply chains an incomplete cold chain leads to significant post-harvest losses. Traditional freshness assessment methods such as candling, floating and the Haugh unit are either subjective, destructive or unsuitable for continuous, in package monitoring. This study evolved and defined a cost-effective, biodegradable colorimetric freshness indicator based on natural lac dye immobilized on Whatman Grade-1 cellulose filter paper. It was designed to detect spoilage-associated volatile compounds principally ammonia through a visible orange-to- purple color transition. The indicator was characterized for its sensitivity to ammonia vapor across a range of concentrations and exposure times, and its performance was validated against eggs of differing structural integrity (intact, old and cracked) stored at room temperature and under refrigeration. The color change in dye sensor was assessed using smartphone-derived RGB values converted to CIELAB color difference (ΔE) and cross-verified with a Lovibond reflectance spectrophotometer. FTIR spectroscopy confirmed that the color transition arises from an acid–base interaction between volatile amines and the hydroxyl and carboxyl groups of the laccaic acids in the dye, and egg weight loss was tracked as a complementary freshness parameter. The indicator responded rapidly and reproducibly to ammonia, distinguished fresh from spoiled eggs, and tracked the accelerated deterioration of cracked and non-refrigerated eggs. The results demonstrate that a lac-dye/filter-paper indicator offers a promising, instrument-free, food-safe approach for real-time egg freshness monitoring in intelligent packaging.