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Relationships between Ultimate pH and Microbial, Chemical, and Physical Characteristics of Vacuum‐Packaged Pork Loins
Author(s) -
Knox B.L.,
Van Laack R.L.J.M.,
Davidson P.M.
Publication year - 2008
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1750-3841.2008.00667.x
Subject(s) - loin , lactic acid , food science , thiobarbituric acid , chemistry , shelf life , tbars , aerobic bacteria , zoology , biochemistry , bacteria , biology , antioxidant , lipid peroxidation , genetics
This study evaluated the effect of ultimate pH (pHu) of pork on shelf life based upon microbial growth, drip loss, and oxidative rancidity (2‐thiobarbituric acid [TBA] procedure) in vacuum‐packaged loins stored at 4 °C. Glucose and lactate concentrations of the pork loins were also measured. Thirty‐six pork loins (pH = 5.56 to 6.57) were collected at a commercial slaughter facility 1‐d postslaughter. All pigs were from the same genetic line. Loins were grouped by pH (group: pH range): A: 5.55 to 5.70, B: 5.71 to 5.85, C: 5.86 to 6.00, D: 6.01 to 6.15, and E: > 6.16. They were analyzed at days 0, 6, 14, 24, and 34. For aerobic plate counts, groups A and B were significantly lower than C through E, while psychrotrophic or Enterobacteriaceae counts of groups A and A through C were significantly lower than groups B through E and D and E, respectively. Lactic acid bacteria counts were not significantly influenced by pHu. Group A had higher glucose concentrations than groups C through E and higher lactate concentrations than groups D through E on most sampling days. Group A had a higher TBA value than group E at days 0 and 34. Group A displayed greater drip loss than groups D and E at day 6 and groups B through D on days 24 and 34. Based on the microbial and drip loss results, a pork loin pHu of 5.8 to 5.9 appears to be optimum to provide a vacuum‐packaged shelf life of at least 24 d with minimum drip loss.