70 Chilled foods 6 20°C 10°C 5°C 0°c Fig. 3.2 Time for odour and slime to develop on beef carcasses at different storage temperatures. tough when it is subsequently cooked. 36 If no cooling is applied and the temperature of the meat is above 25C at completion of rigor then another form of shortening rigor'-or'heat-shortening' will occur Electrical stimulation(ES) of the carcass after slaughter can allow rapic hilling without much of the toughening effect of cold shortening. However, Buts et al.38 reported that in veal ES followed by moderate cooling affected tenderness in an unpredictable way and could result in tougher meat. Electrical stimulation will hasten rigor and cause tenderisation to start earlier at the prevailing higher temperature. In meat from carcasses given high or low voltage stimulation and slow cooling, adequate ageing in beef can be obtained in about half the time of non-stimulated beef This will therefore reduce the requirement nd cost of storage When meat is stored at above freezing temperatures it becomes progressively more tender. This process, known as ageing, conditioning or maturation is traditionally carried out by hanging the carcass for periods of 14 days or longer different times for tenderisation Beef, veal and rabbit age at about the same rate and take about ten days at 1C to achieve 80% of ageing(Table 3.4). Lamb ages slightly faster than beef but more slowly than pork. The ultim depend on the initial'background' tenderness of the meat and the tenderisation that has occurred during chilling. In veal acceptable tenderness can be obtained fter five day ays at IC compared with 10 days for beef. Red colour is more stable at lower temperatures because the rate of oxidation of the pigment decreases. At low temperatures, the solubility of oxygen is greater and oxygen-consuming reactions are slowed down. There is a greater penetration of oxygen into the meat and the meat is redder than at high temperatures The major improvement in tenderness has been shown to occur in less than 14 days. In a study by Martin et al., in which more than 500 animals were examined, it was concluded that for beef carcasses, a period of six days istough when it is subsequently cooked.36 If no cooling is applied and the temperature of the meat is above 25ºC at completion of rigor then another form of shortening ‘rigor’ – or ‘heat-shortening’ will occur.37 Electrical stimulation (ES) of the carcass after slaughter can allow rapid chilling without much of the toughening effect of cold shortening. However, Buts et al.38 reported that in veal ES followed by moderate cooling affected tenderness in an unpredictable way and could result in tougher meat. Electrical stimulation will hasten rigor and cause tenderisation to start earlier at the prevailing higher temperature. In meat from carcasses given high or low voltage stimulation and slow cooling, adequate ageing in beef can be obtained in about half the time of non-stimulated beef38 This will therefore reduce the requirement and cost of storage. When meat is stored at above freezing temperatures it becomes progressively more tender. This process, known as ageing, conditioning or maturation is traditionally carried out by hanging the carcass for periods of 14 days or longer. The rate of ageing differs significantly between species and necessitates different times for tenderisation. Beef, veal and rabbit age at about the same rate and take about ten days at 1ºC to achieve 80% of ageing (Table 3.4). Lamb ages slightly faster than beef but more slowly than pork. The ultimate tenderness will depend on the initial ‘background’ tenderness of the meat and the tenderisation that has occurred during chilling. In veal acceptable tenderness can be obtained after five days at 1ºC compared with 10 days for beef. Red colour is more stable at lower temperatures because the rate of oxidation of the pigment decreases. At low temperatures, the solubility of oxygen is greater and oxygen-consuming reactions are slowed down. There is a greater penetration of oxygen into the meat and the meat is redder than at high temperatures. The major improvement in tenderness has been shown to occur in less than 14 days. In a study by Martin et al., 39 in which more than 500 animals were examined, it was concluded that for beef carcasses, a period of six days is Fig. 3.2 Time for odour and slime to develop on beef carcasses at different storage temperatures. 70 Chilled foods