Quality control of shell eggs EGGS ARE CHECKED FOR CRACKS, DIRT AND BLOOD
The Trade Standards stipulate a quality tolerance on grade A eggs, stating that the number of eggs with quality defects may not exceed 5 % when sending them out. There is a 7 % tolerance for discrepancies in other chains of the trade. The quality control of grade A eggs are carried out by collecting samples as each manufacturer’s eggs are received at the packing company. Each packing machine has built-in sensors to ensure that the eggs are checked for cracks in the shell, dirt, or blood. The machine also tests the weight of the eggs, and finally the packaging machine and the finished products are checked once a week in accordance with the company’s quality management system. Checking shell eggs, the raw product At the manufacturer a sample of the eggs is taken twice a week to ensure that they comply with the requirements of The Trade Standards and the internal requirements laid down for the quality of the raw product. The following aspects are monitored: ·· S hell surface roughness and purity. This is checked visually. ·· Air cell height, measured using an
22 | Quality control of shell eggs
air cell measuring instrument. The height must not exceed 6 mm. Eggs marketed as ‘extra fresh’ can have air cells of no more than 4 mm. ·· Y olk colour is assessed visually using the ‘Yolk Colour Fan’. ·· E gg white height, measured using the Haugh unit, must be greater than 60 %. At the same time the egg white is tested for how fluid and solid it is. Having at least two weekly pickups ensures that the eggs are fresh when received at the packing company. Checking for cracked eggs The packaging machine uses a sound detector to check for cracks in the eggshell. The egg is ‘hit’ in three places by a stamp with a microphone at the end. Each egg is hit four times in those three places. The reflected sound then determines whether the shell is intact or not. Checking for dirty eggs The packaging machine uses cameras to detect if an egg is dirty. Each egg is photographed from multiple angles and the result is compared to a standard image stored in the machine’s programme. Of course, different standards are used for white and brown eggs.
Checking for blood eggs The machine uses fluoroscopy to checks whether the eggs contain blood, by measuring the colour red in the light. Checking the packaging machine The quality department checks the packaging machine weekly. The procedure falls into two parts: Are there any eggs among the Grade A eggs that ought to have been removed? And have any good-quality eggs been deselected. A run of 180 cracked eggs is done while sorting out dirty and blood eggs. Trays of pre-packaged eggs from each of the lines are taken through the packaging machine. From the sorting parameters of the packaging machine, it is determined whether the sorting is acceptable. The Trade Standards are used to determine whether the quality of the packaged product is acceptable. Checking the finished product The finished product is checked by having an employee open trays and containers of eggs to check them for cracks and dirt. The results are logged and used to ensure compliance with The Trade Standards’ quality tolerance regulations.