254 Meat refrigeration Table 12.1 Maximum temperatures(C)measured in meat products after being transported for I h in the boot of a car without protection or within a cooled insulated container Product Unprotected Smoked ham Beef pie 954726 Lasagne Source: Evans et al. 1991 te centre Cool box pate surface Fig. 12.2 Temperature chasse prans te during domestic transportation(source chickens and meat pies placed at ambient temperature reached tempera- tures approaching 10C. Frozen meat products in the cold box kept below 10C for the period of the journey Thin sliced chilled products showed the highest temperature char luring transport, whereas temperature gains in thicker products such hicken and pate(Fig. 12.2)were smaller. A similar trend was seen with the frozen products. After being placed in the domestic refrigerator, warm hilled products required ca 5h before the temperature at the surface was educed below 7C.Warm' frozen products placed in a domestic freezer required at least 5 h to reduce centre product temperatures to below -15C Predictions made using a mathematical model that calculated bacterial growth from temperature/time relationships indicated that increases of up to 1.8 generations in bacterial numbers(Table 12.2) could occur in the chilled foods during this transport and domestic cooling phase. The model assumed that bacteria required a time to acclimatise to the change in tem perature(the lag phase)and that no acclimatisation had occurred duringchickens and meat pies placed at ambient temperature reached tempera￾tures approaching 10°C. Frozen meat products in the cold box kept below -10 °C for the period of the journey. Thin sliced chilled products showed the highest temperature changes during transport, whereas temperature gains in thicker products such as chicken and pâté (Fig. 12.2) were smaller. A similar trend was seen with the frozen products. After being placed in the domestic refrigerator, ‘warm’ chilled products required ca. 5 h before the temperature at the surface was reduced below 7 °C. ‘Warm’ frozen products placed in a domestic freezer required at least 5 h to reduce centre product temperatures to below -15 °C. Predictions made using a mathematical model that calculated bacterial growth from temperature/time relationships indicated that increases of up to 1.8 generations in bacterial numbers (Table 12.2) could occur in the chilled foods during this transport and domestic cooling phase. The model assumed that bacteria required a time to acclimatise to the change in tem￾perature (the lag phase) and that no acclimatisation had occurred during 254 Meat refrigeration Table 12.1 Maximum temperatures (°C) measured in meat products after being transported for 1 h in the boot of a car without protection or within a cooled insulated container Product Unprotected Cool box Minced beef 18 9 Sausage (raw) 28 15 Smoked ham 30 14 Beef pie 24 7 Sausage roll 28 12 Lasagne 21 6 Source: Evans et al., 1991. 0 60 120 180 240 300 360 Time (min) 0 5 10 15 20 25 30 Temperature (°C) Ambient pate centre Ambient pate surface Cool box pate centre Cool box pate surface ˆ ˆ ˆ ˆ ´ ´ ´ ´ Fig. 12.2 Temperature changes in paté during domestic transportation (source: Evans et al., 1991)