A simple and rapid method for recovering enteroviruses from oysters is described. A polycation sewage flocculant promoted cohesion of oyster solids and thereby aided separation of these from the viruses. Recovery of 80 to 100% of experimentally inoculated virus was achieved, and the suspension or extract obtained could be inoculated directly into tissue cultures or concentrated first for greater sensitivity.

Two enteroviruses were inactivated more rapidly in a lake than in sterile lake water; then their coat proteins were degraded and, perhaps, used by microorganisms.

Reovirus type 1, influenza virus type A, and parainfluenza virus type 3 persisted for ≤ 3 days in the low-moisture foods tested. Then enteroviruses tested persisted > 2 weeks at room temperature and > 2 months in the refrigerator. Where storage temperature was not constant, time-temperature effects were roughly cumulative. Inactivation of enteroviruses proceeded at an intermediate rate in foods stored at an intermediate temperature of 12 C. Polioviruses from feces and from tissue cultures were inactivated at comparable rates in foods. The inactivation rate of another enterovirus (ECHO-6) was similar. Neither the presence of feces nor of the fecal microflora seemed to influence the persistence of food-borne poliovirus. The moisture level in a food did not effect poliovirus inactivation under conditions of these tests. At reduced temperatures, virus was extremely stable in foods at pH ≥ 7. At pH 5.5, there was a complex interaction of protein and salt content upon virus stability. Poliovirus was inactivated 10−2 during freeze-drying of cream-style com. The remaining virus was quite stable during storage of the product at 5 C.

A set of simple, rapid filtration methods has been developed for recovering enteroviruses from foods. The methods employ quite inexpensive equipment, and the resulting extract might be concentrated in any of several ways. Three model enteroviruses were apparently recovered with at least 80% efficiency when inoculated, at levels ranging from thousands to one plaque-forming unit per 20-g sample, into eleven foods representing six major food groups.

Grape juice inactivated human enteroviruses, but not parainfluenza type 1 (Sendai) virus, in vitro. The effect was not one of aggregation or of degradation of the virus surface. Some of the inactivated virus adsorbed specifically to host cells, but did not infect them. Most of the inactivated virus could be reactivated by treatment with polyethylene glycol. Grape juice-inactivated virus and coproantibody-neutralized virus were both reactivated by contents of porcine stomach and duodenum, which suggests that ingestion of such viruses would lead to intestinal infection. Grape juice-inactivated virus was efficiently reactivated by human blood serum. Ingested grape juice has not been shown likely to prevent or modify human enterovirus infections.