[Use of flocculants for detection of viruses in fluids (author's transl)]

Hydroxide flocs of iron, aluminium, zinc, and tin were tested for their capabilities of virus enrichment in fluids (such as water and liquid foods). The virus used was polio type II att. The flocculation with tin yielded the best results because it gave the highest recovery rates (90%) and good reproducibility. A satisfactory enrichment was also obtained with the flocculation with aluminium- and iron salts. The losses were 31 and 33%. The lowest recovery rates were obtained with nickel- and zinc flocculation (losses: 70 and 77%). The difficulties in filtering the flocs and eluting the virus with 3% beefextract could be overcome by centrifugation and dissolution of aluminium and iron flocs with sodium-potassium-tartrate (average recovery rates 5 and 27%). In addition we tested the flocculation in lemonade as a model fluid loaded with a high content of organic material which usually interfere with the formation of flocs and in consequence the enrichment of viruses. An enrichment of viruses in lemonade was possible only with previously prepared and aged flocs of tin and iron. The loss was 18 and 12% respectively.