328 Meat refrigeration 16.2 Pastry products 16.2.1 Commercial operations Although it should be a far simpler and quicker operation to reduce the temperature of small individual items, such as meat pies, many manufac turers allow an inadequate length of time for the cooling operation and the products are packaged at temperatures substantially above the storage value. After wrapping and boxing it is very difficult to remove the residual heat. Typically, pie manufacturers allow Ih for their single-stage cooling operations and the core temperature of pies before packing can range from 17to37°C(able16.8) The surface temperature of cooked products is very high when they leave baking ovens and consequently the difference between the surface and the ambient is very large at this time. To reduce energy usage and costs a number of manufacturers operate two-stage cooling operations utilising ambientairfollowedbysubzeroairinthesecondstage(table16.10).com paring the data from the first two examples in Table 16.9 and Table 16.10 it can be seen that similar final product temperatures are produced in the ingle- and two-stage cooling processes. The use of very low temperatures during single-stage cooling operations can produce quality problems due to freezing of the pastry at the surface of the products. In addition with some baked products manufacturers believe that the quality of the pastry suffers if taken below 10C. One minced beef pie manufacturer used air at 12Cin he second stage of a two-stage cooling process to avoid this problem(Table 16.10). However, even when the cooling time was increased by 25%, the ature of the pie was 20C at the packing stage. In two facto large pies(4.5kg) were also produced for catering use or to be sold after Table 16.8 Examples of commercial single-stage cooling of pastry products in the uK Product Type of Air Cooling Temperature Temp. Velocity (h) Initial Final (°C)(ms-2) (°C)(°C) Steak and kidney Spiral 11/170.5 90-9517-20 pie(185g Spiral 90-9517-20 Cold store 1.090-9530 Ambient 1.0 90-9537 Ambient 1.090-9532 Spiral 11/17 355 0.8939610 Pork pie(4.5 kg) Ambient 16-23 Source: James, 1990c16.2 Pastry products 16.2.1 Commercial operations Although it should be a far simpler and quicker operation to reduce the temperature of small individual items, such as meat pies, many manufac￾turers allow an inadequate length of time for the cooling operation and the products are packaged at temperatures substantially above the storage value. After wrapping and boxing it is very difficult to remove the residual heat. Typically, pie manufacturers allow 1 h for their single-stage cooling operations and the core temperature of pies before packing can range from 17 to 37 °C (Table 16.8). The surface temperature of cooked products is very high when they leave baking ovens and consequently the difference between the surface and the ambient is very large at this time. To reduce energy usage and costs a number of manufacturers operate two-stage cooling operations utilising ambient air followed by sub zero air in the second stage (Table 16.10). Com￾paring the data from the first two examples in Table 16.9 and Table 16.10 it can be seen that similar final product temperatures are produced in the single- and two-stage cooling processes. The use of very low temperatures during single-stage cooling operations can produce quality problems due to freezing of the pastry at the surface of the products. In addition with some baked products manufacturers believe that the quality of the pastry suffers if taken below 10 °C. One minced beef pie manufacturer used air at 12 °C in the second stage of a two-stage cooling process to avoid this problem (Table 16.10). However, even when the cooling time was increased by 25%, the core temperature of the pie was 20 °C at the packing stage. In two factories, large pies (4.5 kg) were also produced for catering use or to be sold after 328 Meat refrigeration Table 16.8 Examples of commercial single-stage cooling of pastry products in the UK Product Type of Air Cooling Temperature chiller Temp. Velocity time Initial Final (°C) (ms-1 ) (h) (°C) (°C) Steak and kidney Spiral -11/-17 0.5 1.0 90–95 17–20 pie (185 g) ≤ Spiral -3 3–5 1.0 90–95 17–20 ≤ Cold store -30 <0.2 1.0 90–95 30 ≤ Ambient 20 0.3 1.0 90–95 37 ≤ Ambient 20 3.5 1.0 90–95 32 Sausage rolls Spiral -11/-17 0.5 0.8 93–96 10 Pork pie (4.5 kg) Ambient 16–23 <0.2 8.0 68 25 Source: James, 1990c