Part of this study was presented by S. K. Murray at the Undergraduate Research Paper Forum at the 41st Annual Meeting of the Institute of Food Technologists, Atlanta, GA, June 7–10, 1981. This research was supported by the British Columbia Ministry of Agriculture and Food and by the Canadian Dairy Commission (Contract OSU81–00259).
Effect of Nitrogen Flushing on the Production of Proteinase by Psychrotrophic Bacteria in Raw Milk
Article first published online: 25 AUG 2006
Journal of Food Science
Volume 48, Issue 4, pages 1166–1169, July 1983
How to Cite
MURRAY, S.K., KWAN, K.K.H., SKURA, B.J. and McKELLAR, R.C. (1983), Effect of Nitrogen Flushing on the Production of Proteinase by Psychrotrophic Bacteria in Raw Milk. Journal of Food Science, 48: 1166–1169. doi: 10.1111/j.1365-2621.1983.tb09183.x
- Issue published online: 25 AUG 2006
- Article first published online: 25 AUG 2006
- Ms received 12/27/82; revised 3/7/83; accepted 3/29/83.
Raw milk was flushed with 100 ml N2 min -1 during storage at 4°C. Microflora (total psychrotrophs, proteolytic psychrotrophs, lactic acid bacteria) in nitrogen-flushed milk exhibited a longer lag phase and slower growth rates than those in milk stored aerobically at 4°C. Although proteolytic psychrotrophs grew in nitrogen-flushed milk, proteinases could not be detected in these milk samples. Proteinase assays and electrophoresis showed extensive proteolytic activity and hydrolysis of β-casein in control milk but no detectable casein degradation in nitrogen-flushed milk, even after storage for 18 days at 4°C. This study shows the potential of controlled atmosphere storage of raw milk for inhibition of the accumulation of proteolytic enzymes from psychrotrophic bacteria.