Blast from the past: hep A inactivation in scallops

Raw scallops served at Genki Sushi have been fingered in a Hawaiian hep A outbreak. What if Genki had seared the scallops? According to some historic work, seared scallops aren’t probably hep A risk-reduced scallops either.

Inactivation of Hepatitis A virus in heat-treated mussels
Journal of Applied Microbiology
dec.99
L. CROCI, M. CICCOZZI, D. DE MEDICI, S. DI PASQUALE, A. FIORE, A. MELE and L. TOTI.1999.Hepatitis A is a widespread infectious disease world-wide. In Italy, shellfish consumption was shown to be a major risk factor for hepatitis A infection, especially when these products are eaten raw or slightly cooked. The aim of the present study was to evaluate Hepatitis A virus (HAV) resistance in experimentally contaminated mussels treated at different temperatures (60, 80 and 100 °C) for various times. The presence of HAV was evaluated by cell culture infection and reverse transcriptase-polymerase chain reaction confirmation. The experiments, carried out on HAV suspension and contaminated mussel homogenate both containing about 105 50% tissue culture infectious dose ml−1, showed that, under our experimental conditions, the treatments at 60 °C for 30 min, 80 °C for 10 min and an immersion at 100 °C for 1 min were not sufficient to inactivate all the viruses; it was necessary to prolong the treatment at 100 °C for 2 min to completely inactivate the virus. Thus it is advisable to eat only cooked shellfish, paying particular attention to the times and temperatures used in the cooking process, since evidence suggests that the shellfish body may protect the virus from the heat effect.

Also, here’s the health department’s entire press conference on the source of the outbreak.