This study was undertaken to determine the impact of the moisture enhancement process on the bacterial contamination and storage life of vacuum-packaged pork loins. Bone-in and boneless pork loins injected
with brine (sodium chloride, sodium phosphate, lemon juice) were obtained from a commercial processing facility and stored for 5 weeks in vacuum packaging at 2 and 5°C. At weekly intervals, samples
were excised to determine numbers of spoilage bacteria and pathogens. The loins were subjectively evaluated by a sensory panel to quantify appearance and odor acceptability. Moisture-enhanced loins were
initially contaminated with a population of psychrotrophic bacteria that was approximately 2 log units higher than that for noninjected boneless loins. This difference was largely due to contamination by
larger numbers of pseudomonads in the brineinjected loins. There were no significant differences in the initial numbers of lactic acid bacteria, Enterobacteriaceae, or Brochothrix thermosphacta.
Similar trends in spoilage bacterial populations were observed for moisture-enhanced loins with bones, but Enterobacteriaceae counts were also found to be approximately 1 log unit higher for the
injected product. Brine-injected loins generally had larger bacterial numbers at each storage time, but there were no consistent injection treatment effects on bacterial growth. Brine injection did not affect
color or odor deterioration, and the storage life for vacuum-packaged loins was the same as that for noninjected controls. The incidence of Listeria monocytogenes was 21% for control loins and 27%
for moisture-enhanced loins. Although the brine injection process resulted in an increase in bacterial contamination, there was no evidence that this contamination would affect the storage life of vacuum-packaged
loins, and further research is necessary to determine the significance of the increased incidence of L. monocytogenes.
Document Type: Research Article
Agri-Food Laboratories Branch, Food Safety Division, Alberta Agriculture, Food and Rural Development, 5th floor, O.S. Longman Building, 6909-116
Street, Edmonton, Alberta, Canada T6H 4P 2:
Lacombe Research Centre, Agriculture and Agri-Food Canada, Lacombe, Alberta, Canada
Publication date: February 1, 2003
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