[Cottage-industry and semi-industrial ice-creams. Incidence of Staphylococcus aureus and enterotoxigenicity].

Sixty seven samples of ice-creams were taken from seven different semi-industrial and small-scale shops. 43.3% of the samples were positive for the investigation of Staphylococcus aureus in 1 g; 88% showed less than 10 St. aureus in 1 g; 10.5% between 10 and 100 and 1.5% between 101 and 1,000. In 29 strains was investigated enterotoxigenicity, as well as the response to different biochemical tests and the susceptibility to antibiotics: 21% of the strains were toxigenic (4 produced enterotoxin A, 1 enterotoxin B and 1 enterotoxins A and D). There was no difference between the toxigenic and non-toxigenic strains when biochemical tests were performed (catalase test, coagulase test, thermostable nuclease production, anaerobic utilization of glucose and mannitol, gelatin and casein hydrolysis, production of hemolysins and pigments). All the strains showed susceptibility to different antibiotics. On the basis of the present study it is proposed to incorporate in article 1075 of the Argentine Food Code the limit of 100 Staphylococcus aureus in 1 g of ice creams.