Efficacy of Commonly Used Disinfectants for the Inactivation of Calicivirus on Strawberry, Lettuce, and a Food-Contact Surface

Abstract

Norwalk and Norwalk-like viruses (NLVs) are important causes of foodborne gastroenteritis in restaurant-related outbreaks. Efficacy of common disinfection methods against these viruses on food-contact surfaces and fresh produce is not known partially because of their nonculturability. Seven commercial disinfectants for food-contact surfaces and three sanitizers for fruits and vegetables were tested against cultivable feline calicivirus (FCV). Disks of stainless steel, strawberry, and lettuce were contaminated with known amounts of FCV. The disinfectants were applied at one, two, and four times the manufacturer's recommended concentrations for contact times of 1 and 10 min. The action of disinfectant was stopped by dilution, and the number of surviving FCVs was determined by titration in cell cultures. An agent was considered effective if it reduced the virus titer by at least 3 log10 from an initial level of 10(7) 50% tissue culture infective dose. None of the disinfectants was effective when used at the manufacturer's recommended concentration for 10 min. Phenolic compounds, when used at two to four times the recommended concentration, completely inactivated FCV on contact surfaces. A combination of quaternary ammonium compound and sodium carbonate was effective on contact surfaces at twice the recommended concentration. Rinsing of produce with water alone reduced virus titer by 2 log10. On artificially contaminated strawberry and lettuce, peroxyacetic acid and hydrogen peroxide was the only effective formulation when used at four times the manufacturers' recommended concentration for 10 min. These findings suggest that FCV and perhaps NLVs are very resistant to commercial disinfectants. However, phenolic compounds at two to four times their recommended concentrations appear to be effective at decontaminating environmental surfaces and may help control foodborne outbreaks of calicivirus in restaurants.

Comparative Virucidal Efficacy of Seven Disinfectants Against Murine Norovirus and Feline Calicivirus, Surrogates of Human Norovirus

“…The effect on the genomic copy number was significant but lower than that of other biocidal products such as sodium hypochlorite for example; again, this finding is in accordance with the results of Fraisse et al (2011). FCV seems to be more sensitive to sodium hypochlorite and to PAA than MNV (Gulati et al 2001;Baert et al 2009b;D'Souza and Su 2010;Fraisse et al 2011;Park and Sobsey 2011;Kim et al 2012;Vimont et al 2015); therefore FCV could overestimate the effect of these two biocides on HuNoV.…”

Scientific Opinion on an update on the present knowledge on the occurrence and control of foodborne viruses

“…The application of higher concentrations is limited due to sensorial aspects. Prolonging the chlorine treatment would not be useful to increase the efficacy of chlorination since two studies showed that a contact time beyond 10 min made little difference in antiviral activity towards FCV Gulati et al, 2001). EFSA Journal 2011;9(7):2190…”

“…The application of 200 ppm chlorine to treat strawberries and lettuce did not result in an additional reduction of FCV compared to washing with tap water (Gulati et al, 2001). …”

“…Peroxyacetic acid (PAA) at a concentration of 150 mg/L was tested by (Gulati et al, 2001) to treat strawberries and lettuce, resulting respectively in 1 and 2 log reduction of FCV compared to washing with water. Allwood et al, (2004) showed a comparable decline of MS2 and FCV in the case 200 mg/L chlorine, 3% H 2 O 2 and 80 mg/L PAA were used as sanitizers.…”

Microbial Control of Fresh Produce using Electrolyzed Water

“…Chlorinated water (100-300 ppm chlorine) has also been shown to reduce E. coli O157:H7 inoculated strawberries by less than 1.5 log 10 CFU/g 36,55 . Moreover, chlorinated water (800 ppm chlorine) was reported to reduce Feline calicivirus (FCV) by only 1 log 10 FCV/g on the strawberry 16 . These results can be attributed to the surface structure of the strawberry fruit.…”