The effects of hot water pasteurizing treatments on the appearances of pork and beef

Portions of post- and pre-rigor pork and beef were treated by immersion in water of 75 or 85 degrees C for 5, 10, 15 or 20 s. The appearances of untreated and treated cut muscle, fat, membrane covered and cut bone surfaces, and the over all appearances of treated and untreated meat pieces, were assessed by a 5-member panel 2 hr and 24 hr after each treatment. At those times, CIE L*a*b* values were obtained for cut-muscle surfaces. The appearances of surfaces covered by membrane, of fat and cut bone surfaces of pre-rigor pork and beef, and of fat and cut bone surfaces of post-rigor pork, were not persistently degraded by any treatment. However, the appearances of fat and cut bone surfaces of post-rigor beef were persistently degraded by the harsher treatments, apparently, because of pre-treatment staining of fat and changes in the bone marrow. Panel scores for the overall appearance and for the appearance of cut muscle surfaces were generally the same for each meat piece. All treatments caused patchy bleaching of cut muscle. The degraded appearances of pre- and post-rigor pork and post-rigor beef muscle persisted at 24 hr, but the appearances of beef muscle treated pre-rigor improved between 2 and 24 hr. Most treated muscle gave increased CIE L* values and decreased a* and b* values as compared with untreated portions fr om the same primal cut. However, CIE b* values for pre-rigor beef muscle were higher than for untreated muscle 2 hr after treatment, but lower than for untreated muscle 24 hr after treatment. It appears that pasteurizing treatments cannot be applied to meat without some degradation of the appearances of cut muscle surfaces, which will persist in pork treated pre- or post-rigor and in beef treated post-rigor, but which will partially resolve during the storage of beef treated pre-rigor. (C) 1997 Elsevier Science Ltd.