TITLE:
Efficacy of Antimicrobial Lauric Arginate against Listeria monocytogenes on Stainless Steel Coupons
AUTHORS:
Jasdeep K. Saini, Miguel A. Barrios, James L. Marsden, Kelly J. K. Getty, Daniel Y. C. Fung
KEYWORDS:
Lauric Arginate; Listeria monocytogenes; Stainless Steel Coupons
JOURNAL NAME:
Advances in Microbiology,
Vol.3 No.1,
March
28,
2013
ABSTRACT:
Commercially processed foods become contaminated with Listeria monocytogenes in
post-processing environments where favorable conditions help the bacteria
thrive. The US Food and Drug Administration has approved Lauric arginate
(LAE) as generally recognized as safe (GRAS) for certain food applications.
This study evaluated the efficacy of Mirenat-N (LAE dissolved in food-grade
propylene glycol) against L.
monocytogenes on food contact surfaces. A three-strain cocktail of L. monocytogenes was used to inoculate
24 polished stainless steel coupons with three treatments, 100 ppm and
200 ppm solutions of LAE and water (control); two sub-treatments of high (6 log
CFU/ml) and low (4 log CFU/ml) inoculum levels; and two contact times of 5 and
15 min. Attached bacteria were dislodged by vortexing coupons for 1 min with 20 g of 3-mm solid glass beads in 10 ml of
0.1% peptone diluent, and bacterial populations were calculated by plating onto
modified oxford medium (MOX) and thin agar layer MOX (TALMOX). The 100 ppm
treatment showed average reductions of 1.38 and 2.57 log CFU/coupon at the low
inoculum level and 0.37 and 0.62 log CFU/coupon
at high inoculum levels, after 5 and 15 min exposure, respectively. For 200 ppm
at the high inoculum level, 1.23 and 1.88 log CFU/coupon reductions were
seen for 5 and 15 min, respectively; the low inoculum level at 5 and 15 min
exposure showed reductions of ≤1.5 log CFU/coupon. The 100 ppm LAE
treatment was more effective at low inoculum levels for 5 and 15 min contact times
and may be used to control low levels of contamination of L. monocytogenes on food contact surfaces.