100 Meat refrigeration 6.2 Conventional chilling The majority of carcass meat is chilled in conventional chill rooms nomi nally operating at one or sometimes two conditions during the chilling cycle Most of the factors that control the chilling process are common to all species and are covered in the following section on beef. Specific consid- erations for sheepmeat, pork and offal are outlined in their respective sections. 6.2.1 Beef This section brings together design data on many aspects of the chilling of beef sides. Effects of environmental, carcass and operational variables on the rate of chilling and evaporative weight loss in single stage air chilling systems are described in detail. Data are also presented on the rate of heat release from sides that are encountered in these cooling operations Using conventional single stage chilling regimes it is evident that only relatively light(<105 kg), lean beef sides can be cooled to 7C in the deep leg during a 24 h operating cycle, whilst evaporative losses are of the order of 2% Despite the general absence of specific regulations for chilling time, the time required to cool a side to a specified maximum temperature is the most important commercial factor determining the cost and operation of a cooling system. If sides cannot be chilled within 18h, which is the time avail able in one day, making allowance for loading, unloading and cleaning, they will probably remain in chill for a further 24 h. Chilling facilities will then have to be twice as large, with considerably increased capital investment and running costs. Some investigations on the continuous chilling of beef (Drumm et al., 1992a, b) have been carried out but such systems are not widely used Increasing attention is now being paid to the reduction in energy con sumption, but it has been shown that in commercial chilling operations the cost of evaporative weight loss in beef sides(Collett and Gigiel, 1986)are at least an order of magnitude higher than the energy costs. Major investigations to provide such data have been carried out at Food Refrigeration and Process Engineering Research Centre(FRPERC) Langford(formerly the Meat Research Institute)(Bailey and Cox, 1976; Cox and Bailey, 1978)and at the National Mechanical Engineering Research Institute, Pretoria(Kerens and Visser, 1978; Kerens, 1981). Pub- lished information from these investigations and others has been brought together in this section together with some unpublished material 6.2.1.1 Effect of environmental and carcass variables on cooling rate Air temperature, air velocity, and to a limited extent, relative humidity, are the environmental factors that affect the cooling time of beef sides. Cooling rate will also be a function of the weight and fat cover of a given side6.2 Conventional chilling The majority of carcass meat is chilled in conventional chill rooms nomi￾nally operating at one or sometimes two conditions during the chilling cycle. Most of the factors that control the chilling process are common to all species and are covered in the following section on beef. Specific consid￾erations for sheepmeat, pork and offal are outlined in their respective sections. 6.2.1 Beef This section brings together design data on many aspects of the chilling of beef sides. Effects of environmental, carcass and operational variables on the rate of chilling and evaporative weight loss in single stage air chilling systems are described in detail. Data are also presented on the rate of heat release from sides that are encountered in these cooling operations. Using conventional single stage chilling regimes it is evident that only relatively light (<105 kg), lean beef sides can be cooled to 7 °C in the deep leg during a 24 h operating cycle, whilst evaporative losses are of the order of 2%. Despite the general absence of specific regulations for chilling time, the time required to cool a side to a specified maximum temperature is the most important commercial factor determining the cost and operation of a cooling system. If sides cannot be chilled within 18h, which is the time avail￾able in one day, making allowance for loading, unloading and cleaning, they will probably remain in chill for a further 24h. Chilling facilities will then have to be twice as large, with considerably increased capital investment and running costs. Some investigations on the continuous chilling of beef (Drumm et al., 1992a,b) have been carried out but such systems are not widely used. Increasing attention is now being paid to the reduction in energy con￾sumption, but it has been shown that in commercial chilling operations the cost of evaporative weight loss in beef sides (Collett and Gigiel, 1986) are at least an order of magnitude higher than the energy costs. Major investigations to provide such data have been carried out at Food Refrigeration and Process Engineering Research Centre (FRPERC), Langford (formerly the Meat Research Institute) (Bailey and Cox, 1976; Cox and Bailey, 1978) and at the National Mechanical Engineering Research Institute, Pretoria (Kerens and Visser, 1978; Kerens, 1981). Pub￾lished information from these investigations and others has been brought together in this section together with some unpublished material. 6.2.1.1 Effect of environmental and carcass variables on cooling rate Air temperature, air velocity, and to a limited extent, relative humidity, are the environmental factors that affect the cooling time of beef sides. Cooling rate will also be a function of the weight and fat cover of a given side. 100 Meat refrigeration