M. longissimus thoracis et lumborum from 64 bull beef carcasses were selected based on their pH values. The meat pH was measured 48 h post slaughter by inserting calibrated pH and temperature probes (Mettler Toledo MP 125 pH meter with an Inlab 427 probe) directly into the muscle/meat. Duplicate readings were taken for analysis of each sample. Twelve of the samples were used for various calibrations and trial runs and the remaining 52 samples ranging in ultimate pH from 5.4 to 6.9 (Table 1) were vacuum packed and stored in a −1.5 °C chiller until the freezing point analysis, which was carried out over a period of 8 weeks. An insulated box was designed and built to control the rate of temperature decline in the samples during freezing (Fig. 1). The box could hold six meat samples, with each sample filling a plastic specimen bottle
(no lid) 42 mm diameter and 55 mm high. A T-type thermocouple probe was constructed [using 40 fine gauge (0.2mm wire diameter, Class 1 Tolerance; calibrated against an RT200 reference thermometer)] for each of the 6 samples using a 14 gaugeMonoject™hypodermic needle. The thermocouple tip was insulated to prevent heat transfer from the metal of the needle. The thermocouple sensors were fixed into the lid such that it would always be located in the physical centre of the product sample when the rig was assembled.