The job of cleaning dirty eggs in a manner that will not damage the quality of the eggs has long been a tedious and time consuming one.
There is little question that washing is the quickest and easiest method of removing visible dirt from the shells of eggs. However, washed eggs are at present discounted on certain markets, particularly for cold storage purposes.
The reason for this is no doubt due to the unsanitary manner in which the eggs are often washed and to quite general opinion that washing removes the natural "bloom" from the shell, thus permitting a greater loss of moisture. Washing large numbers of dirty eggs with a damp cloth or even in a pail of water no doubt spread bacteria through the whole lot of eggs, thus increasing the spoilage. This is particularly true if could water is used.
The new machine washes the eggs in a sanitary manner, and, according to a test, removes a negligible amount of the "bloom." The eggs are fed into the machine between moving fingers that carry the eggs in back of revolving wet abrasive-coated cloth disks where the cleaning is done. From a tube above the disks the hot water (165 degrees F. or hotter at the disks) drips down on the disks to the eggs where it softens and loosens the dirt so that the disks can more readily clean the eggs. The water flushes down through the machine and runs to waste, taking the dirt with it. The disks are self-scouring and are constantly flushed with hot water. The hot water may be obtained from any convenient source, but to insure the desired minimum temperature an automatic water heating attachment is being developed.
Thus, the eggs are flush-washed with clean water that is hot enough to kill the common spoilage bacteria that may be on the outside of the eggshells. The ends of the eggs are cleaned as well as the sides, and the action of the disks is so gentle that seldom is an egg broken. In fact, cracked eggs can be washed.
After the washing of the eggs, they are carried by the moving fingers around to the front of the machine and are rolled across the drier to the discharging opening. A piece of toweling in the drier quickly absorbs the free water from the eggs and a blast of hot air completes the drying. The eggs are dry enough to pack when they roll out of the machine on the receiving tray. Another machine has been developed which will transfer the eggs from the drier to a grader.
The eggs are in the washer for 22 seconds and an equal length of time in the drier. The temperature of the eggs at the discharge is only two degrees above that at the feed end. The rapid evaporation of the moisture in the drier removes most of the heat picked up by the eggs while in the washer.
Five Cases an Hour
The machine has the capacity to wash and dry approximately five cases of eggs per hour. By use of the attachment for transferring the eggs to a grader, it is possible for two people to wash, dry, grade and pack at the rate of five cases per hour.
Although the machine has adequate capacity for large producing establishments, it has been designed to meet the needs of the small operator with only a few hundred birds.
In cooperation with Dr. G. O. Hall of Poultry Husbandry and Dr. C. N. Stark of Bacteriology at Cornell University, tests have been made on the keeping quality of eggs washed in the machine.
Samples of fresh, nest run eggs were soiled with chicken manure and cultures of the common bacteria that cause eggs to spoil, stored at room temperature (70-75 degrees F.) for a day, then washed in the machine, using cold water, warm water, hot water, soapy water and with chlorine solution of 500 ppm. After washing, all samples, including the "nest clean" untreated samples, were stored under a controlled temperature of 81 degrees and a relative humidity of 85 per cent or more for a period of 33 days. This was estimated to be the equivalent of six months in cold storage.
Washed Eggs Keep
At the end of the storage period, the eggs were candled and broken out to test for quality, spoilage and any damage that might have been done by the hot water. It was found that in every case where the washing was done with water at 165 degrees F. or higher, the treated washed eggs kept just as well as the untreated nest clean eggs. The samples washed in cold water or warm water did not keep as well.
There was no visible evidence of damage having been done to the interior of the eggs by the hot water.
This new type of cleaner should make it possible for poultrymen to clean eggs conveniently and quickly in a sanitary manner immediately after gathering, so that they can be packed or stored in better condition than has been the general practice heretofore.
- From the American Agriculturist