Survival of viruses on fresh produce, using MS2 as a surrogate for norovirus

AIMS: To study the survival and removal of viruses from fresh fruit and vegetables using the bacteriophage MS2 as a potential surrogate for noroviruses. METHOD AND RESULTS: Survival of MS2 in buffer and on fresh produce was studied at 4, 8 and 22 degrees C. At 4 and 8 degrees C a reduction of <1 log10 was observed after 50 days in buffer; however a reduction in excess of 1 log10 occurred within 9 days at 22 degrees C. Similar results were obtained with fresh produce with virus survival times exceeding the shelf life of the produce. In washing experiments, using a chlorine wash (100 ppm), in all but one case <1.5 log10 MS2 bacteriophage was removed from fruit and vegetables. The mean across all produce types was 0.89 log10. With potable water, reduction was lower (0.3 log mean across all produce types). CONCLUSIONS: MS2 survived for prolonged periods, both in buffer and on fresh produce, at temperatures relevant to chilled foods. It was not removed effectively by chlorine washing. SIGNIFICANCE AND IMPACT OF THE STUDY: Bacteriophage MS2 has been evaluated as a potential surrogate for noroviruses on fresh produce. Experimental results together with current knowledge of norovirus resistance and survival indicate that MS2 could be used as an effective surrogate in future evaluations.