Submitted to: Journal of Food Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/30/2002
Publication Date: 11/1/2002
Citation: Murphy, R.Y., Duncan, L.K., Berrang, M.E., Driscoll, K.H., Marcy, J.A. 2002. Effect of packaging film thickness on thermal inactivation of salmonella and listeria innocua in fully cooked chicken breast meat. Journal of Food Science. 67(9):3435-3440. Interpretive Summary: Fully cooked poultry meat products have been implicated in human illness due to the presence of microbial pathogens. A post cook pasteurization step after packaging can help to lower the numbers or eliminate human bacterial pathogens that can contaminate product between cooking and packaging. Cooked poultry meat may be packaged in several different types of plastic films. This study was undertaken to determine if the thickness of packaging film makes a difference in the effectiveness of a heat treatment applied to fully cooked chicken breast meat. Cooked breast meat was inoculated, packaged in films of either 0.0762 mm or 0.2032 mm in thicknesses. Heat treatment was applied by placing in a hot water bath (68 C) for times ranging from 10 s to 120 s. Results showed that meat packaged with the thicker film underwent a slower heating rate which affected the rate of bacterial death. Commercial poultry meat processors who wish to use post packaging pasteurization procedures to ensure the microbial safety of their products can use this information to aid in packaging and processing decisions.
Technical Abstract: This study was conducted to determine the effect of film thickness used in vacuum packaging on thermal inactivation of Salmonella and Listeria innocua. Fully cooked chicken breast meat products were ground and inoculated to contain 10 7 cfu/g of Salmonella or L. innouca. A thin layer (0.5 mm thick) of the inoculated product was vacuum-packaged using 0.0762mm or 0.2032 mm thick films. The packaged meat was heat-treated in a water bath at 68 degrees C for 10 - 120 s and then immediately cooled in an ice-water bath. After treatments, the enumeration was conducted to determine the survivors of Salmonella or L. innocua. A paired comparison was conducted to determine whether packaging film thickness affected thermal inactivation of Salmonella or Listeria. The effect of film thickness on thermal inactivation of Salmonella or L. innouca interacted with heating time. More than two log 10 difference could be obtained between the meat that was packaged in the two different film thicknesses.