Eggshell colour affecting the safety and quality of Japanese quail eggs (Coturnix coturnix japonica).

1. This study determined the presence of Salmonella spp. on the shell of Japanese quail eggs of different colour and to examine effects of eggshell colour on the internal and external quality characteristics and chemical composition of eggs. A total of 360 Japanese quail eggs derived from the same farm (near Belgrade, Serbia) were divided into two groups based on shell colour: brown-spotted (n = 180) and blue (n = 180) eggs.2. Out of 360 Japanese quail eggs examined, Salmonella spp. was found on the shells of 12 samples (3.33%), all of which originated from blue quail eggs (6.67%).3. Blue quail eggs had higher egg weight, dirty eggs, egg width and E_{whole egg} value, but lower eggshell dirtiness score, percentage of normal-shaped eggs and eggshell thickness. Brown-spotted quail eggs had a higher albumen percentage and height, Haugh units, albumen index, yolk height, index and L* and b* value. Contrarily, blue quail eggs had higher albumen pH and width, yolk weight, percentage and width and a* value.4. A higher occurrence of meat and blood spots was detected in blue quail eggs. Blue quail eggs had higher content of proteins, fats, dry matter, ash, oleic acid, linoleic acid, polyunsaturated fatty acids (PUFAs), monounsaturated fatty acids (MUFAs) and Σn-6. They had higher nutritive value index, hypocholesterolaemia/hypercholesterolemic index, n-6/n-3 ratio and PUFA/SFA ratio. Contrarily, brown-spotted quail eggs had higher content of moisture, palmitic acid, palmitoleic acid, stearic acid, elaidic acid and saturated fatty acids (SFAs), as well as higher atherogenic and thrombogenic index.5. In conclusion, brown-spotted quail eggs are safer for consumption and have higher internal and external quality characteristics, whereas blue quail eggs have more favourable chemical composition, fatty acid profile and lipid indexes.