4 Meat refrigeration Table 2.7 Temperatures in pig carcasses during cooling quickly and slowly Time after slaughter(h) Temperature(°C Deep leg Longissimus dorsi Quick Slow Quick 5 460 700 Source: Tay Table 2.8 Drip loss after 43h at 0C from longissimus dorsi samples removed from slowly and quickly cooled beef sides Cooling meth Range drip by wt) Ratio drip. Slow Quick Quick 1 0.2-3.2 0.1-20 0.84.1 0.6-1.8 3.6-4.4 0.9-2.1 2.9 Source: Taylor, 1972. 3 6h at 15C +41 h at 0'C(still air) 423 h at 15°C+24hato°c( still air) Opposite sides of the same animal were used for comparison and drip was measured in four 25. 4 mm thick slices of l dorsi cut between the 9th and 10th ribs and stored at 0C for 43h. The saving in drip gained by cooling quickly after slaughter was clearly shown(Table 2. 8). The mean loss from e samples taken from sides cooled quickly by method 2 was 1.1% Other subsequent studies have shown that rapid chilling, as long as freez ing of the muscle or cold shortening is avoided, will substantially reduce ip loss. Gigiel et al.(1985)removed cylindrical samples of muscle from freshly slaughtered beef. The curved surface and one end of the cylinder were sur- rounded by insulation and the free end placed in contact with solid carbon dioxide(CO2). Since heat was only extracted from one end this produced a wide range of cooling rates through the length of the cylinder. After cooling and equalisation, the cylinder was cut into discs and the drip poten tial of each disc measured using a centrifuge technique described by Taylor (1982). The resulting plot of drip loss against cooling rate is shown in(Fig 2.7). Close to the surface in contact with the co the rate of cooling was3 6 h at 15 °C + 41 h at 0°C (still air) 4 23 h at 15 °C + 24 h at 0°C (still air). Opposite sides of the same animal were used for comparison and drip was measured in four 25.4mm thick slices of l. dorsi cut between the 9th and 10th ribs and stored at 0°C for 43h. The saving in drip gained by cooling quickly after slaughter was clearly shown (Table 2.8). The mean loss from the samples taken from sides cooled quickly by method 2 was 1.1%, while that from sides cooled at the slowest rate, method 4, was 2.7%. Other subsequent studies have shown that rapid chilling, as long as freez￾ing of the muscle or cold shortening is avoided, will substantially reduce drip loss. Gigiel et al. (1985) removed cylindrical samples of muscle from freshly slaughtered beef. The curved surface and one end of the cylinder were sur￾rounded by insulation and the free end placed in contact with solid carbon dioxide (CO2). Since heat was only extracted from one end this produced a wide range of cooling rates through the length of the cylinder. After cooling and equalisation, the cylinder was cut into discs and the drip poten￾tial of each disc measured using a centrifuge technique described by Taylor (1982). The resulting plot of drip loss against cooling rate is shown in (Fig. 2.7). Close to the surface in contact with the CO2 the rate of cooling was 34 Meat refrigeration Table 2.7 Temperatures in pig carcasses during cooling quickly and slowly Time after slaughter (h) Temperature ( °C) Deep leg Longissimus dorsi Slow Quick Slow Quick 5 30 19 24 7 10 14 5 6 0 15 3 0 0 0 Source: Taylor, 1972. Table 2.8 Drip loss after 43 h at 0 °C from longissimus dorsi samples removed from slowly and quickly cooled beef sides Cooling method Range drip (% by wt) Ratio drip, Slow Quick Slow Quick slow/quick 3 1 0.2–3.2 0.1–2.0 2.2 4 2 0.8–4.1 0.6–1.8 2.4 4 1 3.6–4.4 0.9–2.1 2.9 Source: Taylor, 1972