Beef Carcass Flash Chilling Question

[idesign]

Hello Guys
I am new owner to meat plant.I need some suggestion on how to quickly chill the carcass below 4 degree celcius.My cooler runs preety good but it takes whole day to chill the hot carcass .Can some1 suggest me what kind of unit i should be installing so i can chill carcass asap.currently my cooler compressor is 16K BTU.
I have i whole freezer unit 25kBTU.Can freezer unit be installed in cooler and run both time so that air temperature is below 0 all time and carcass chills fast.Please let me know ur suggestion.

[nobow]

Sounds like you need a very large blast chiller.

[nike123]

You cannot cool carcases faster if you do not want to freeze them.

CHILLING

To prevent or even to reduce the deterioration process, particularly microorganism development, chilling has to be carried out quickly after carcass dousing at the end of the slaughter process and the chilled state has to be maintained until the meat is processed for consumption.
Chilling can be defined as the fundamental operation in applying cold to meat to reduce its temperature quickly. This is done in a cold chamber with intensive air draught or movement. Rapid cooling of the meat surface not only slows and nearly stops the development of surface micro-organisms but also reduces weight loss and discoloration of the surface owing to haemoglobin oxidation. Different systems of primary chilling are in use (including immersion in iced water, especially for poultry) but air chilling is the most common.
The cold chambers where chilling takes place must have a low air temperature, a high air speed, a high relative humidity and a high refrigerating capacity.
Air temperature must be in the region of 0°C, with no decrease below -1°C, which could freeze the meat surface and impair its appearance.
Air speed can range from 0.25 to 3.0 m/s. However, for economical reasons the most common speeds in use are from 0.75 to 1.5 m/s in the empty section of the cold chamber.
Air speed over the carcasses will be much higher because of the reduction in air circulation. Increased air speed reduces the cooling period but it has a limit as there is a threshold above which fan-power consumption increases more than the chilling rate, resulting in an increase in operational costs. Also, the higher the air speed the greater the weight loss.
Relative humidity during the chilling operation should be kept fairly high to prevent excessive weight loss. The recommended rate is between 90 and 95 percent, though this is the most difficult factor to control.
Primary chilling is completed when the warmest point of the carcass has reached a temperature of about 7°C (3°C for edible offal). With current technology these temperatures can be arrived at in 16–24 hours in small carcasses and in less than 48 hours in large carcasses (centre of the hind leg). Average and surface temperatures are obviously much lower, reaching 0°C on the surface within four hours; this is important to slow microbial proliferation.
Quick chilling has its problems, cold shortening being the most common. Cold shortening can often be seen in beef and mutton, when the meat, still in its pre-rigor phase, reaches temperatures of 10°C or lower. These conditions cause irreversible contractions of the muscle tissue which toughen the meat even after prolonged ripening.
Quick primary chilling also signifies an increase in investment and higher operational costs. The chilling period can be reduced by lowering the air temperature (surface freezing risks) or increasing air speed (higher operational costs) or both. Occasionally cold chambers are refrigerated in advance to reach lower temperatures than those in operation (-5°C/-6°C for beef; -10°C/-12°C for pork), taking advantage of thermal inertia to offset the effect of warm meat loads.
Quick primary chilling can be performed in small chambers or in cooling tunnels. In cold chambers it is carried out in two or three phases. During the first phase the air temperature is maintained at about 0°C, carefully controlling the risk of superficial freezing while air movement is maintained at a high level. For large carcasses, after 10–12 hours the air circulation inside the store is reduced, maintaining temperature and humidity conditions; this second phase lasts another six to 10 hours. After this period the meat is transferred to cold storage chambers where the carcass temperature is stabilized, concluding the third phase.
Small cold chambers used for chilling must be designed so their capacity can be filled in two hours at the slaughterhouse's normal work rate. The number of chambers should be sufficient for a peak working day. Particular care should be taken that warm humid carcasses are placed behind those already chilled or in the process of being chilled so that the air, which is still cold, reaches them and there is no risk of superficial condensation.
Cooling tunnels used for chilling meat are usually of the continuous type. Here again meat is subjected to a two-phase process, with conditions similar to the cold chamber. However the temperature can be as low as -5°C for a short time. Beef carcasses can reach an average temperature of about 15°C in a four-hour period, while pork and mutton reach the same temperature in two to two and a half hours. Surface temperature decreases to 4–5 °C. During the second phase, conditions are less exacting, and an average temperature of about 4°C is stabilized after 15–16 hours in a secondary refrigerating chamber. This method is used in high-capacity slaughterhouses particularly for pig carcasses; for beef and mutton slower cooling is recommended because of the dangers of cold shortening.

http://www.fao.org/docrep/004/T0098E/T0098E02.htm

[mad fridgie]

You can look into spray chill. (a fine mist of chilled water introduced into the air flow) The airflow must be correct for the application, not just a question of spraying some water into the air.
Local regulations may need to be followed (it is possible for the product to gain weight, which generally is not allowed)

[Magoo]

Nike123
your article covers everything brilliantly.

[Fridgetek]

Its all about air velocity

[Magoo]

Correct, air velocity at minimal moisture removal from product, high sensible heat factor evaporators.
Difficulty is the deep butt / hind quarter temps. Surface bacterial levels with high humidity, it is a fine art to acheive.
I prefer vertical down air flow from linear slot defusers above hanging rail, which requires a false plenium above rails, and air pressure to suit

[mikeref]

The abattoir here uses high velocity evaporators at each end of the room. About 50 head to each room and each beast is hung in halves over night. (Less hide, hooves head and innards of course.) We have around 48 KW/H cooling capacity, so 16 hours brings the halves down to +2 C and ready for the butchers in the processing room.

Meat burn, or drying out of the outer layer is regulated by specifically timed off cycles, where one unit is shut down and it's evaporator fans continue to run, effectively allowing defrost and humidity to rise while the other chiller continues it's work. Both are then back on line for some hours before the cycle reverses.l
A data logger monitors meat temperature over night.

[Fridgetek]

The problem with that method is that sensible heat from the fans causes the refrigeration system to run and latent heat then removed from the product. This causes weight loss.