Surfactant-enhanced disinfection of the human norovirus surrogate, Tulane virus, with organic acids and surfactant

Authors: LACOMBE, ALISON - National College Of Natural Medicine; Niemira, Brendan; Gurtler, Joshua; Kingsley, David; LI, XINHUI - University Of Wisconsin; CHEN, HAIQIANG - University Of Delaware

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/2017
Publication Date: 1/23/2018
Citation: Lacombe, A., Niemira, B.A., Gurtler, J., Kingsley, D.H., Li, X., Chen, H. 2018. Surfactant-enhanced disinfection of the human norovirus surrogate, Tulane virus, with organic acids and surfactant. Journal of Food Protection. 81(2):279-283.

Interpretive Summary: Norovirus is a major cause of foodborne illnesses, and measures are being sought to destroy the virus in food. A model virus, used in place of the pathogenic Norovirus is the Tulane virus, which was used in this study. This experiment examined the use of phenolic or short-chained organic acids (SCOA)to destroy Tulane virus. Gallic acid (GA), tannic acid (TA), p-coumaric acid (PC), lactic (LA) or acetic acid (AA), in combination with sodium dodecyl sulfate (SDS) was tested against Tulane virus. Results indicated that the combination that killed the greatest amount of virus was 0.5 percent LA plus 0.7 percent SDS, which inactivated 4.5 log of Tulane virus.

Technical Abstract: Combination treatments of surfactants and phenolic or short-chained organic acids (SCOA) may act synergistically or additively as sanitizers to inactive foodborne viruses and prevent outbreaks. The purpose of this study was to investigate the effect of gallic acid (GA), tannic acid (TA), p-coumaric acid (PC), lactic (LA) or acetic acid (AA), in combination with sodium dodecyl sulfate (SDS) against Tulane virus (TV), a surrogate for human norovirus. An aqueous stock solution of phenolic or SCOA with or without SDS was prepared and diluted in a two-fold dilution series to 2x of the desired concentration with cell growth media (M119 + 10% FBS). The solution was inoculated with an equal proportion of 6 log PFU/ml TV with a treatment time of 5 min. The survival of TV was quantified using a plaque assay with LLC-MK2 cells. The minimum virucidal concentration (MVC) was 0.5/0.7 percent (v/v) for LA/ SDS at pH 3.5 (4.5 PFU/ml reduction) and 0.5/0.7 percent (v/v) AA/SDS at pH 4.0 (2.6 log PFU/ml reduction). GA and SDS demonstrated a MVC of 12.5 mM GA/SDS at pH 7.0 (0.2/0.3 percent GA/SDS) with an 0.8 log PFU/ml reduction and 50 mM GA/SDS (0.8/1.4 percent GA/SDS pH 7) increased log reduction to 1.6 log PFU/ml. The combination treatments of AA or LA with SDS at pH 7.0 did not produce significant log reduction, nor did individuals treatments of TA, GA, PC, AA, LA, or SDS, respectively. This study demonstrates that a surfactant, such as SDS, aids in the phenolic acid and SCOA toxicity against viruses. However, inactivation of TV by combination treatments is contingent upon the pH of the sanitizing solution being lower than the pKa of the organic acid being used. This information can be used to develop sanitizing washes to disinfect food contact surfaces, aiding in the prevention of foodborne outbreaks.