Transfer of MS2 bacteriophage from surfaces to raspberry and pitanga fruits and virus survival in response to sanitization, frozen storage and preservation technologies

This study assessed the norovirus (NoV) surrogate bacteriophage MS2 transfer from stainless steel, glass and low-density polypropylene surfaces to raspberry and pitanga fruits. The effect of sodium hypochlorite (100 ppm, 1 min) on MS2 survival on whole fruits, the MS2 survival in sanitized fruits and derived pulps during frozen storage, and in response to preservation technologies (heat, organic acids and salts) was also assessed. The highest (p < 0.05) viral transfer (%) was observed from glass and stainless steel (similar to 90%) to raspberry, and from glass and polypropylene (similar to 75%) to pitanga, after 60 min of contact. Sodium hypochlorite reduced (p < 0.05) MS2 titer by 3.5 and 3.8 log PFU/g in raspberry and pitanga, respectively. MS2 decreased (p < 0.05) up to 1.4 log PFU/g in frozen stored sanitized fruits (whole fruits and pulps) after 15 days, with no further changes after 30 days. Thermal treatments reduced MS2 titer (p < 0.05) in both fruit pulps. MS2 inactivation was higher in pitanga pulp. The addition of ascorbic acid, citric acid, sodium benzoate, or sodium metabisulfite had little effect (<1 log PFU/g) on MS2 concentration in either fruit. These results may inform NoV risk management practice in processing and handling of fruits.