Effect of Freezing and Microbial Growth on Myoglobin Derivatives of Beef

Abstract

The effect of freezing and bacterial growth on the discoloration of beef was assessed by measuring myoglobin derivatives myoglobin (MB), oxymyoglobin (MBO(2)), and metmyoglobin (METMB) on the surfaces of fresh and frozen-thawed packaged beef cuts stored at 2 degrees C and analyzed after 0, 3, 6, 9, and 12 days of storage. MB, MBO(2), and METMB concentrations were measured spectrophotometrically. Frozen-thawed beef samples experienced less "blooming" (conversion of MB to MBO(2)) and more rapid discoloration than fresh cuts during storage. By day 3, >20% METMB was formed in the frozen-thawed samples, whereas the fresh samples reached this value after day 6 of storage. The rates of MB oxidation were similar (P > 0.05) for sterile and frozen-thawed inoculated (Pseudomonas fluorescens at a rate of 1.5 colony forming units/cm(2).cm(2) area) samples from day 0 through day 6 of storage. For storage periods of less than a week, bacterial growth is not a major cause of meat discoloration. After day 6, the high bacterial growth rate resulted in a rapid increase in METMB formation. Possible mechanisms for MB oxidation in frozen-thawed beef are suggested.

Oxidative stability of previously frozen ostrich Muscularis iliofibularis packaged under different modified atmospheric conditions

“…In Figure S2 an upward trend in the pH is visible, with final pH values significantly higher than day 0 for all three treatments. The marked increase in pH observed, also reported by Abdallah et al (1999), is thought to originate from Pseudomonas utilising amino acids as their main energy source instead of glucose, once the glucose reserves have been depleted (Gill, 1996). The deamination of the amino acids results in the formation of ammonia (NH 3 ) formed by the addition of an H + to the NH 2 − group cleaved from the amino acid.…”

Does It Look Cooked? A Review of Factors That Influence Cooked Meat Color

“…Van Laack and others (1996b) could not attribute changes in myoglobin denaturation or a* value brought about by frozen storage to any differences in reducing capacity, concentration of metMb or cooking method, though the differences in product formulation and cooking from frozen are likely to have had some influence in their study. Ben Abdallah and others (1999) compared the concentration of each form of myoglobin between raw beef cuts that had undergone a freeze–slow thaw cycle and fresh beef cuts. When both were stored at 2 °C in the dark in gas‐impermeable film, the previously frozen meat contained significantly more metMb and less oxyMb than the fresh meat for most of the experiment.…”

Inter-relationships between the metrics of instrumental meat color and microbial growth during aerobic storage of beef at 4°C

“…Several studies have been carried out to investigate microbial-induced discoloration by inoculating specific bacteria (mainly Pseudomonas spp.) to the sterile meat surface (Robach & Costilow, 1961;Chan, et al, 1998;Abdallah, et al, 1999;Motoyama et al, 2010), however, as far as we acknowledge, there is few report studying the inter-relationship between meet discoloration and microbial growth for naturally contaminated meat under aerobic storage conditions.…”