The effects of ozone, ultrasound and coating with shellac and lysozyme–chitosan on fresh egg during storage at ambient temperature. Part II: microbial quality, eggshell breaking strength and FT‐NIR spectral analysis

Summary This research aims to investigate and compare the effect of different treatments, including gaseous ozone (6‐ppm/4‐min), ultrasound (450 W/4‐min), and coatings of shellac and lysozyme–chitosan (L–C), on fresh eggs during the storage for six weeks at ambient temperature. The internal quality analysis was performed in Part I. In Part II, the bacterial qualities, Fourier transform near‐infrared (FT‐NIR) spectral image and eggshell breaking strength were monitored. Ozone and ultrasound helped to maintain bacterial quality, but had an adverse effect on shell strength. Coated eggs had the highest value of strength (shellac: 3.63 ± 0.54 kgf; L–C: 3.56 ± 0.54 kgf) and ultrasound‐treated eggs had the lowest strength (3.13 ± 0.78 kgf) in egg top. FT‐NIR measurement showed that all treatments resulted in a decrease in absorption bands throughout storage. Overall, among the treatments investigated, the coatings were the best for enhancing shelf life with higher strength in eggshell breakage, while the ozone and ultrasound only helped to keep the microbial quality and enhance the shelf life.