For the successful processing and subsequent sale of poultry meat, processors and retailers need to work together closely.
On the whole, this works as those employed at these two stages are committed to ensuring that the hygienic conditions achieved during processing are not lost further along the line. Once product is dispatched from the processing plant, retailers are committed to ensuring that the microbiological status of processed birds is not compromised through any subsequent cold chain lapse.
Of course, things can go wrong, and there are some areas that need to be monitored in real time at processing and once product has left the plant, so that immediate action can be taken if necessary.
At the plant
Chickens arrive at the processing plant in cages or other containers. Being live, all of their physiological processes are active, including defecation. Because full cages are stacked, any feces from birds at the top of the stack will fall onto birds below adhering to feathers and skin.
In hot countries, once loaded trucks are weighed, they pass through a car wash which cleans the chickens with diluted disinfectant. This helps to reduce the organic load that may be on the feathers and skin and also refreshes the birds, thus reducing death due to heat stress.
However, while waiting to enter the plant, the physiological processes do not stop, and so birds will continue to be soiled. Additionally, upon removal from the cages and hanging on the overhead line, shock can lead to further defecation, as can transport to the stunner.
If stunning is reversible, the birds are not dead, and they will struggle with pain in the bleeding tunnel. This also can result in defecation.
Simply put, immediately before entering the scalder, large amounts of fecal matter can be seen on the feathers and skin.
Cleaning the chicken
The poor sanitary state of birds prior to entering the scalding tank needs to be improved as much as possible to reduce their bacterial load, as the tank offers an ideal opportunity for cross contamination.
To remedy this, many plants have installed special washers with rotating brushes that remove as much fecal matter as possible from the skin and feathers.
Using this approach, combined with monitoring the volume of water used in the scalding tanks – 1-2 liters per bird entered – along with the continuous removal of the foam resulting from denatured protein plasma and which helps to concentrate the bacterial load, many plants have managed to keep water quality at an acceptable level. Addition of strong acids can also be used as a way of keeping bacterial counts low.
Birds leave the tank with a raised body temperature, resulting in dilation of the follicles and a consequent loosing of the feathers. If efforts are not made to maintain this temperature, then birds will cool during the plucking process making feather removal more difficult. Consequently, plucking machines will need to be adjusted to ensure that all feathers are removed, particularly those of the tail and the wings.
This, however, can result in additional expulsion of feces. In some cases, small amounts can become lodged in the open follicles on removal of the feathers. When rubber fingers exert excessive pressure, matter is pushed right into the follicle.
A solution is to pass the carcasses through a special washer where a water and disinfectant spray can remove some bacteria.
The quality of feed withdrawal has an impact on the sanitary status of chickens during evisceration, particularly because of the high risk of rupturing the crop and intestinal fragility that can occur when feed withdrawal is short or long, respectively. Should the crop or intestines rupture then legal requirements demand that birds are sent for reprocessing to disinfect the carcasses, before eviscerated can be completed.
Proper drainage of carcasses, following spraying with disinfectant, is sometimes overlooked. Because bleeding continues after evisceration, if water held in the abdominal cavity is not properly drained, it will take on a reddish appearance and result in an increase in the organic load going to the next stage in the process, which is chilling.
Chilling the bird
Chilling comprises two stages – pre-chilling and chilling – and requires a greater supply of antimicrobials to keep the bacterial count within acceptable levels. Achieving this can be helped by having a water temperature that is lower than the temperature of the carcasses.
- In the pre-chiller, the water temperature should be 22–28C; maintaining the temperature within this range can prevent damage to muscle tissue that can occur if carcasses are suddenly entered into water of a much lower temperature
- In the chiller, water temperature should be close to 0C to effectively stop bacterial growth
It should be noted that proper compliance with recommended water supplies – again 1-2 liters per carcass entered – will greatly help to keep bacteria levels in the water down.
It is also worth remembering that the chilling process will result in water around the carcass being absorbed. Consequently, it is important to monitor the bacteria count in real time before carcasses leave the chiller as this is a sanitary Critical Control Point, and it will affect shelf life. It should be remembered that the average temperature of the carcasses on leaving the chiller should be close to 2C.
At packing, it is important to prevent bottlenecks that could result in the temperature of the carcasses rising. For biosecurity reasons, the packing area needs to operate with a temperature of 8–10C, as this will help carcasses to maintain an ideal temperature during grading and packing.
If the cold chain is to remain uncompromised, then packaged chickens need to enter the refrigeration or freezing process with a maximum temperature of 4C. When a carcass has a temperature of 0C, bacteria will only multiply once every 20 hours. Should the temperature reach 4C, then this multiplication will take place every 8 hours, accelerating deterioration and reducing shelf life.
Within storage rooms, the following aspects should be monitored:
- There should be no variation in temperatures, as this can result in recrystalization problems in frozen products
- Relative humidity should be high to prevent product from drying out
- There should be an adequate space between stored items to allow the free airflow
- PVC plastic curtains should be hung so that when doors are open, exterior air does not enter; an inflow of warmer air will affect the efficiency of the refrigeration equipment and result in temperature variation
- Storage room doors should close tightly
During shipping to the distributor, attention must be paid to the following:
- The dispatch area should have an ambient temperature of no more than 10C
- The temperature of products needs to be checked before entering the truck:
- Fresh: 0 – 2C
- Refrigerate: -2 – 2C
- Frozen: -18 – -12C
- Loading should be completed as quickly as possible to prevent any rise in temperature;
- The container truck should not have any leaks, as this will allow the entry of warmer air.
At the distributor
Once product arrives at the client’s premises, it must be unloaded, weighed and stored in the coolers as quickly as possible to minimize temperature variation. These steps need to be monitored to ensure that there has been no deviation from the temperature when goods were dispatched.
The processor’s responsibility does not end with the delivery to the distributor, and so it is important to verify that storage in cold rooms and freezers is correct. That there is proper rotation and that the quantity of product displayed in the cold rooms and freezers does not exceed manufacturers’ recommendations also needs to be verified.
Paying careful attention to the various points mentioned above can help to ensure the maximum shelf life.