Bacteriophage significantly reduces Listeria monocytogenes on raw salmon fillet tissue

Authors: SONI, KAMLESHHUMAR - Mississippi State University; NANNAPANENI, RAMAKRISHNA - Mississippi State University

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2009
Publication Date: 1/1/2010
Citation: Soni, K., Nannapaneni, R. 2010. Bacteriophage significantly reduces Listeria monocytogenes on raw salmon fillet tissue. Journal of Food Protection. 73:32-38.

Interpretive Summary: This work adds to the proof of the use of bacteriophage to combat Listeria in seafood products.

Technical Abstract: We have demonstrated the antilisterial activity of generally recognized as safe (GRAS) bacteriophage LISTEX P100 (phage P100) on the surface of raw salmon fillet tissue against Listeria monocytogenes serotypes 1/2a and 4b. In a broth model system, phage P100 completely inhibited L. monocytogenes growth at 4 degrees Celsius for 12 days, at 10 degrees Celsius for 8 days, and at 30 degrees Celsius for 4 days, at all three phage concentrations of 10(4), 10(6), and 10(8) PFU/ml. On raw salmon fillet tissue, a higher phage concentration of 10(8) PFU/g was required to yield 1.8-, 2.5-, and 3.5-log CFU/g reductions of L. monocytogenes from its initial loads of 2, 3, and 4.5 log CFU/g at 4 or 22 degrees Celsius. Over the 10 days of storage at 4 degrees Celsius, L. monocytogenes growth was inhibited by phage P100 on the raw salmon fillet tissue to as low as 0.3 log CFU/g versus normal growth of 2.6 log CFU/g in the absence of phage. Phage P100 remained stable on the raw salmon fillet tissue over a 10-day storage period, with only a marginal loss of 0.6 log PFU/g from an initial phage treatment of 8 log PFU/g. These findings illustrate that the GRAS bacteriophage LISTEX P100 is listericidal on raw salmon fillets and is useful in quantitatively reducing L. monocytogenes.