Listeria monocytogenes detection on food contact surfaces: suitability of different swab materials

The high binding capacity of Listeria monocytogenes to food contact surfaces increases the risk of cross-contamination in food. In addition to appropriate cleaning and disinfection procedures, a suitable sampling plan and technique for the earliest possible detection are necessary for prevention. This paper evaluates the sensitivity of 3 swab materials (cotton, viscose and nylon-flocked) for the qualitative and quantitative detection of L. monocytogenes on food contact surfaces (100 cm2). A L. monocytogenes cocktail of 3 serotypes (IIa, IIb and IVb) was applied to stainless steel, polyvinyl chloride, polytetrafluoroethylene and high-density polyethylene surfaces at a concentration of approx. 1.0 x 10(1)-1.0 x 10(2) CFU/100 cm2 and approx. 4.0 x 10(4) CFU/100 cm(2). The surfaces were sampled after 15 min of incubation by 3 different swabs using the double-swab technique, and then stored for 4 and 24 h until processing. The results of the qualitative and quantitative tests showed a few statistically significant differences in the detectability of L. monocytogenes by different swab materials, which implies that the detection rate of L. monocytogenes on a certain food contact surfaces can be increased by using the respective most suitable swab.

Automated summary

The high binding capacity of Listeria monocytogenes to food contact surfaces increases the risk of cross-contamination in food. A suitable sampling plan and technique for the earliest possible detection are necessary for prevention. This study evaluates the sensitivity of 3 swab materials for the detection of L. monocytogenes on food contact surfaces and suggests that using the most suitable swab can increase the detection rate.