Removal and transfer of viruses on food contact surfaces by cleaning cloths

Abstract

Contamination of food contact surfaces with pathogens is considered an important vehicle for the indirect transmission of food-borne diseases. Five different cleaning cloths were assessed for the ability to remove viruses from food contact surfaces (stainless steel surface and nonporous solid surface) and to transfer viruses back to these surfaces. Cleaning cloths evaluated include two different cellulose/cotton cloths, one microfiber cloth, one nonwoven cloth, and one cotton terry bar towel. Four viral surrogates (murine norovirus [MNV], feline calicivirus [FCV], bacteriophages PRD1 and MS2) were included. Removal of FCV from stainless steel was significantly greater (P ≤ 0.05) than that from nonporous solid surface, and overall removal of MNV from both surfaces was significantly less (P ≤ 0.05) than that of FCV and PRD1. Additionally, the terry towel removed significantly fewer total viruses (P ≤ 0.05) than the microfiber and one of the cotton/cellulose cloths. The cleaning cloth experiments were repeated with human norovirus. For transfer of viruses from cloth to surface, both cellulose/cotton cloths and microfiber transferred an average of 3.4 and 8.5 total PFU, respectively, to both surfaces, and the amounts transferred were significantly different (P ≤ 0.05) from those for the nonwoven cloth and terry towel (309 and 331 total PFU, respectively). There was no statistically significant difference (P > 0.05) in the amount of virus transfer between surfaces. These data indicate that while the cleaning cloths assessed here can remove viruses from surfaces, some cloths may also transfer a significant amount of viruses back to food contact surfaces.

Fig 1

Virus removal from solid surface (A) and stainless steel (B) by cleaning cloth and virus type. Error bars indicate standard deviations. *, only dry microfiber was included in these data for MNV removal, and thus, the data were excluded from statistical analyses, as dry microfiber was determined to be significantly different from dampened cleaning cloths; a, statistically significant difference (P = 0.0031) in removal of FCV from solid surface and stainless steel; b, statistically significant difference in removal of MNV from both surfaces compared to FCV and PRD1 removal (P = 0.0016 and 0.0004, respectively).

Fig 2

Total virus (FCV, MS2, PRD1) transfer to solid surface and stainless steel by cleaning cloths. Error bars indicate standard deviations. Letters above the bars represent statistically significant differences (P ≤ 0.05) between cloth types for virus transfer within each surface type.