How to maintain broiler carcass quality during evisceration

Learn how proper broiler management and monitoring from the start of feed withdrawal can maximize yields during chicken evisceration.

Several factors can contribute to how successfully broilers are eviscerated during poultry processing, and consequently the processing plant’s final yield.

Broiler management prior to arrival at the plant, and the care with which evisceration is carried out can make the difference between meeting and failing output targets.

Ensuring good evisceration starts with making sure the feed withdrawal period is properly managed, if the following problems are to be avoided.

Short feed withdrawal

If the feed withdrawal period prior to slaughter is too short, this can lead to several issues which will affect the evisceration operations.

Unlike humans, chickens do not have a diaphragm. If the withdrawal period had been too short, any remaining ingested feed will, when the birds are hung on the overhead conveyor, exert pressure on the esophagus, preventing the chickens from breathing properly.

This will result in wing flapping, particularly in the bleed tunnel, and the resultant damage to carcasses can lead to them being rejected.

An overly short feed withdrawal period can also result in feed still being in the crop after the broilers exit the last plucker, increasing the risk of internal carcass contamination. Should the crop break, any remaining feed will escape. Some will adhere to the abdominal cavity fat and be impossible to remove during reprocessing. Contaminated carcasses will have to be either partially or completely rejected.

This type of contamination can have a significant impact on yields.

It is also worth remembering that when intestines are full of feed, they will tend to lie closer to the vent. When the latter is removed, the intestines may be accidentally cut, resulting in internal and/or external carcass contamination, resulting in birds being sent for reprocessing or being rejected altogether.

Long feed withdrawal

If the feed withdrawal period is too long, intestines will weaken due to dehydration, and the risk of them splitting and fecal matter escaping rises. This is of particular concern during vent and intestine removal, and fecal matter on carcasses may lead to them being rejected.

Removing the gallbladder

A broiler’s gallbladder will continue to produce bile up until the moment the bird is slaughtered. However, during the feed withdrawal period, the gallbladder will increase in size, and this raises the risk that it will break during removal. Any spilt bile has the potential to stain the inside and the outside of the carcass. If not washed off within 15 seconds, this staining will become indelible, leading to partial or total condemnation of the bird.

Bile staining of the carcass can lead to partial or total condemnation. | Eduardo Cervantes López

Importance of the liver

The liver is an energy bank that will shrink as it supplies glucose and energy. While liver depletion will not affect the carcass yield, any shrinkage will reduce the processing plant’s total output if giblets are considered as part of the total plant yield.

Care with crop and trachea

Dehydration can lead to the crop and trachea strongly adhering to the abdominal cavity, making their removal all the more difficult.

Care must be taken that their removal does not lead to the loss of valuable skin, so reducing yield. It has been established that 1 centimeter of skin has an average weight of 5 grams which, while small in itself, can affect total yield when multiplied by the number of birds processed.

Full crops increase the risk of carcass contamination. | Eduardo Cervantes López

Head removal

Ideally, the head should be removed at the point of the first neck, or atlas, vertebra. Yet despite equipment designed to do exactly this, the reality is that the head is not always removed at the point that it should be.

An additional inch is often removed. This small additional section has a weight, without skin, of approximately 25 grams. While this may seem small, if multiplied by the number of birds processed in a day, then losses mount.

Removing the feet

In many processing plants, the cut made to remove the paws is a few millimeters below the joint. The cut is made at this point to add a few additional grams to the final yield, but also to stop allow for any skin shrinkage on the thigh, which would otherwise reveal the meat underneath, and which consumers tend to reject.

Take care with vent removal

Some equipment manufacturers guarantee that, after correct feed withdrawal, damage to the intestines will occur in less than 7 percent of birds at vent cutting.

However, only when all variables have been properly considered will vent cutting be successful. It should be remembered that the quality of the blade edge will have a significant impact in ensuring that it is only the vent that is removed.

Cutting the abdomen

Whether the cut is transverse or longitudinal, blade quality will again have a significant influence on the success of this procedure and, if not done properly, the carcass may be completely rejected.

Another check that needs be regularly made is on the loss of abdominal fat, which has an average weight of 40 grams. If the longitudinal cut is not properly made, there is the risk that, with the removal of the intestinal package, fat is either partially or wholly removed. Fat can account for 1.5-2 percent of the live weight of a broiler.

Even in those plants that employ the latest technology to eviscerate birds, there is still a need to monitor performance to ensure that target yields are achieved.