Abstract:  At first, gray sufu producing mucor supplied by sufu manufacturer in Harbin was identified in the study. The producing mucor was identified for M.racemosu in the end. The second, the pathogenicity of M.racemosu was also studied. The pathogenicity experiments of M.racemosu were completed by injecting the suspension of different levels of spores in celiac of mice, observing poisoning symptom, death condition and the weight changes of mice within 30 d, meanwhile, the mice which had died and was executed were anatomized. The viscera including brain, liver, spleen, kidney, lung, heart were collected to examinate pathological changes by HE dye and the counts of survival M.racemosus. The result indicated that the mucor can result in heart, brain, liver, kidney, spleen and lung making pathological changes, especially liver. M.racemosu can mainly result in the putrescence focus of liver of mice. The counts of survival M.racemosus in viscera would increase with increase of injected the counts of M.racemosus spore. In the 5×106 and 5×107 dosage groups , living spore can be observed in all viscera at the same time. And there was positive relationship between living spore and dosage. But, there was not positive relationship between pathogenicity and dosage.

Key words: gray sufu, M.racemosus, identification, pathogenicity