A Blow to the Government

The spreading European rejection of Spanish food exports is seen here as another blow to the troubled Government of Prime Minister Leopoldo Calvo Sotelo, which has been widely perceived as sluggish and inept in its responses to the adulteration scandal.

''This of course is first of all a tragic public health problem,'' said a European diplomat here who has been closely monitoring the implications of the mass poisoning. ''but I think the Spanish authorities are only beginning to realize that it could become an economic catastrophe as well.''

In a parliamentary debate on the question last month, the opposition Socialist Party called for the censure of five ministers, including Health Minister Jesus Sancho Rof, who took off on vacation this summer when specialists were still disputing the exact origins of the poisoning.

Since then, investigators have pinpointed a handful of companies that imported denatured rapeseed oil, which had been specifically treated with aniline to make it fit only for industrial use, and others that had processed it at high temperatures to rid it of its chemical taste and color. It appears that either this processing or the manner in which the oil was transported converted the aniline into a substance, anilide, which may be a toxic agent in combination with rapeseed oil. 21 Brands Listed as Toxic

A total of 21 brands of cooking oil, which in many cases had been sold by ambulatory vendors, have so far been listed as toxic by the Government, which believes that the bulk of the poison oil has now been withdrawn from the market. But only yesterday in Madrid a shop was discovered selling one of the first brands to have been banned.