Lysosomal enzyme release from macrophages: a model of food yeast toxicity evaluation.

The role of lysosomal enzyme released by macrophages was examined in relation to the toxic effect caused by food yeast. Mouse peritoneal macrophages exposed to yeast in culture showed marked release of N-acetyl glucosaminidase, beta-galactosaminidase and beta-glucuronidase below the median lethal dose (LD50). LD50 was measured from the dose response curves of the cytoplasmic lactate dehydrogenase enzyme. Saccharomyces cerevisiae showed the highest LD50 followed by Kluyveromyces fragilis and Candida utilis yeast. LD50 values obtained as well as the in vitro lysosomal release by mouse peritoneal macrophages may be relevant to assess the toxic capacity of food yeast intended for human consumption.