The effect of cranberry juice and cranberry proanthocyanidins on the infectivity of human enteric viral surrogates

The effect of cranberry juice (CJ) and cranberry proanthocyanidins (PAC) on the infectivity of human enteric virus surrogates, murine norovirus (MNV-1), feline calicivirus (FCV-F9), MS2(ssRNA) bacteriophage, and phiX-174(ssDNA) bacteriophage was studied. Viruses at high (∼7 log 10 PFU/ml) or low (∼5 log 10 PFU/ml) titers were mixed with equal volumes of CJ, 0.30, 0.60, and 1.20 mg/ml final PAC concentration, or water and incubated for 1 h at room temperature. Viral infectivity after treatments was evaluated using standardized plaque assays. At low viral titers, FCV-F9 was undetectable after exposure to CJ or the three tested PAC solutions. MNV-1 was reduced by 2.06 log 10 PFU/ml with CJ, and 2.63, 2.75, and 2.95 log 10 PFU/ml with 0.15, 0.30, and 0.60 mg/ml PAC, respectively. MS2 titers were reduced by 1.14 log 10 PFU/ml with CJ, and 0.55, 0.80, and 0.96 log 10 PFU/ml with 0.15, 0.30, and 0.60 mg/ml PAC, respectively. ϕ-X174 titers were reduced by 1.79 log 10 PFU/ml with CJ, and 1.95, 3.67, and 4.98 log 10 PFU/ml with PAC at 0.15, 0.30, and 0.60 mg/ml, respectively. Experiments using high titers showed similar trends but with decreased effects. CJ and PAC show promise as natural anti-virals that could potentially be exploited for foodborne viral illness treatment and prevention.