It was clear from the outset that food matrices presented special problems with respect to virus detection. Quite small quantities of virus needed to be separated from the solid phase of the food sample (and any incident microflora), concentrated to a small volume of fluid, and inoculated into a susceptible cell culture. There were no concerns at that time regarding PCR inhibitors, but many other complications. Shellfish were an early concern because of their association with outbreaks of HA (Koff et al. 1967; Mosley 1967) . T. G. Metcalf, then at the University of New Hampshire, pioneered laboratory studies on the association of enteric viruses with oysters (Metcalf and Stiles 1965) . He made several further contributions to environmental and shellfish virology there and after his move to the Baylor College of Medicine (Atmar et al. 1995 (Atmar et al. , 1996 Stiles 1967, 1968; Metcalf et al. 1979 Metcalf et al. , 1980a Metcalf et al. , b, 1995 .