Effects of Washing and Nanocomposite Active Coating of Carboxymethyl Cellulose Containing Nanoclay and Marjoram Extract (Origanum vulgare L) on the Internal Quality and Eggshell during Cold Storage

Eggs are susceptible to chemical and microbial spoilages due to the presence of nutrients in them as well as several pores in their shells. To preserve egg quality, approaches based on inactivation of microorganisms in egg shells and coatings were used. In this study, effects of using water washing and shell coating with active nanocomposite coating of carboxymethyl cellulose containing nanoclay and marjoram extract on the internal quality and egg shell were investigated.
 Materials &

Eggs in four groups of control (unwashed and uncoated), washed and uncoated, unwashed and coated, and washed and coated were treated during a 4-week storage time at refrigerator temperature (4 oC ±1) within three replications. Weekly physical, chemical and microbial parameters were assessed in egg shell, albumen and yolk.

At the end of the storage time, the lowest total microbial viable count of the shell (0.80 log cfu/ml), the lowest proportion of weight loss (1.01%), the lowest albumen pH (7.71), the highest average of Haugh units (43.82) and yolk index (0.34) were reported in washed and coated eggs (p < 0.05). Experimental treatments included no significant effects on shell thickness; however, shell strength in coated eggs was significantly higher than that in uncoated groups (p < 0.05). Results showed that egg shell washing included no significant effects on the egg quality characteristics, regardless of coating.

In general, washing with water and use of active nanocomposite coating based on carboxymethyl cellulose can be used to improve and preserve egg internal quality and shell during 4-week of storage at refrigerator temperature.