Electrophoresis is commonly used in species determination of proteins in food products; however, its utilization for detection of fraudulent liver mixing in foie gras canned products has not yet been reported. An aqueous extract was first prepared by homogenization in 8M urea and 1 mM dithiothreitol followed by centrifugation. Triton X-100 urea disc-electrophoresis in polyacrylamide gel then was carried out in a cationic system by stacking at pH 5.13 and resolution at pH 4.01. Gels were compared after densitometric scanning. Foie gras containing varying proportions of liver mixtures were assayed. The technique was shown to be effective in detecting liver species adulteration at concentrations as low as 10%.

SummarySurvival or inactivation of hum an and animal viruses III food, water, wastes has been studied extensively.In France, the most popular varieties of cheese, such as Camembert, Brie, Coulommiers are still prepared with raw milk, out side of heat-treated milks. These soft cheeses make up 31 % of ail cheeses consumed. 354000 tons were manufactured in 1985. Consumption is regularly increasing by 2 % each year.We studied the stability of 2 bovine enteroviruses: rotavirus and coronavirus, suspended in raw and sterilized bovine pre-cheese milks. The conditions of temperature, pH, rennet action and sodium chloride concentration examined in this study are those used routinely in the manufacture of soft cheeses.The 2 viruses have a remarquable stability to low temperatures, acid pH, calf rennet and sodium chloride. The results are suggestive of a possible viral persistence in soft cheeses prepared with raw or heat-treated bovine milks.

After experimental contamination of bovine raw and heattreated milks with bovine rotavirus and coronavirus strains, we observed a strong viral inhibition only with raw milks, from which virus recovery was 5 x 10^%. Between 30% and 80% of the virus was recovered from the heat-treated milks, depending on the level of inoculation. The antiviral substance is heatlabile (destroyed within 30 min at 100°C), precipitated by ammonium sulfate and filtrable (0.45 fjim Millipore membrane). It also has neutralizing activity on tissue culture. Preparation of virus stocksBovine rotavirus. Strain RF 45, was kindly supplied by J. Laporte. Briefly, the MA 104 monolayers were washed with MEM and incubated for 3 h at 37°C. The rotavirus strain was inoculated at a low multiplicity of infection (MOI): 0.1 plaqueforming unit/cell (PFU); after 1 h of adsorption, MEM containing 10 (xg of trypsin/ml, and 0.16% tryptose phosphate broth was added. After complete cytopathogenic effect (CPE), cells were disrupted by three cycles of freezing-thawing. The viral suspension was centrifuged, then the supernatant liquid was filtered through a 0.22-fjun Millipore membrane. The virus stock was stored at -20°C, in 1-ml tubes. The final titer was estimated at 4 x 10 9 PFU/ml. Bovine coronavirus. Strain G 110, was kindly supplied by J. Laporte. The HRT 18 monolayers were washed with RPMI. The coronavirus strain was inoculated at MOI: 0.1 PFU/cell. After 1 h of adsorption, the maintenance medium was added.

Étude sur les conditions de production d'ochratoxine A dans les saucissons secs par Ch. LABIE* et Mme Sylviane T�cnE* RÉSUMÉ Le saucisson sec constitue un substrat sur lequel peuvent se développer des moisissures toxinogènes de type Aspergillus ochraceus. Celles-ci sont capables d'élaborer de l'ochratoxine A (80 à 120 ppb) pendant les premiers jours de la fabrication du saucisson, quand la teneur en eau du substrat est élevée et quand les conditions d'environnement sont favorables (température supérieure à .2()o C ; hygrométrie de 80p100 au moins). L'ochratoxine ainsi formée dans la pâte du saucisson reste stable pendant plusieurs semaines.

Au cours d'un épisode pathologique ayant sévi dans une exploitation de porcs, il a pu être isolé, pour la première fois en France, un virus influenza du porc Hsw1N1, accompagné d'une flore microbienne pathogène. Le virus ne s'est pas transmis à l'homme et l’origine du contage est restée inconnue.