Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 3/2/2007
Publication Date: 7/14/2007
Citation: Van Hekken, D.L., Wall, R.J., Somkuti, G.A., Tomasula, P.M. (Abstract) 2007. Fate of lysostaphin in milk through the cheesemaking process. 2007. Journal of Dairy Science. 90:(Suppl 1):270 Interpretive Summary: n/a
Technical Abstract: Transgenic cows secreting over 3 ug lysostaphin/mL milk are usually resistant to mastitis caused by Staphylococcus aureus, but it is unclear if active lysostaphin will persist through dairy processing steps or impact the production of fermented dairy foods. The objective of this study was to determine the fate of lysostaphin as milk is pasteurized and then processed into cheese. Raw milk from transgenic cows was heat treated at 63 deg C for 30 min, 73 deg C for 15 sec (HTST), and 135 deg C for 2 sec. Only the HTST milk was processed into a semi-hard cheese. Aliquots were taken at each processing step and assayed to determine the quantity (ELISA) and activity (ability to inhibit S. aureus growth) of lysostaphin. Results indicated that the majority of the lysostaphin was present in the skim milk portion and was not affected by pasteurization. Although the quantity and activity of the lysostaphin decreased during cheesemaking, active lysostaphin was present in the whey and cheese, even after 90 d of 4 deg C aging. Because lysostaphin is not a natural milk constituent, further research is required to evaluate its potential as a bioprotective agent against staphylococci and its impact on food quality.