No abstract

A new subspecies, Staphylococcus aureus subsp. anaerobius, is described on the basis of a study of 84 strains isolated from young sheep affected by the so-called "abscess disease." The strains of this new subspecies grow well under anaerobic conditions, but not at all or only very weakly under aerobic conditions. They are catalase and benzidine negative and form small unpigmented colonies. Anaerobically they produce L-lactic acid from glucose. The chemical composition of the cell wall, the results of deoxyribonucleic acid-deoxyribonucleic acid hybridization experiments, and the immunological relationships among L-lactate dehydrogenases demonstrated that these strains are closely related to Staphylococcus aureus. The type strain is strain MVF-7(= ATCC 35844).

The behavior of aflatoxins I$, BZ, G1, G2, and M1 was investigated during manufacture, ripening, refrigeration, and frozen storage of Manchego-type cheese. More aflatoxins (per weight or volume) occurred in curd than in whey, although total quantity was greater in whey. Aflatoxins B,, BZ, and M1 remained stable during ripening, but G, and G2 levels increased. Concentration of B,, BZ, and M1 decreased after 15 and 30 days refrigeration storage, but after 60 days 100% recovery occurred in the inner portion and only 60% in the outer. Concentrations of G, and G2 also decreased during the first 30 days, but on day 60 an increase was observed, 200% in the inner and 120% in the outer portions. Aflatoxins were stable after 90 days in frozen storage.

Mycobacterium bovis is a slowly growing microorganism, and confirmation of the diagnosis by conventional culture is a lengthy process. A simple, rapid method for the extraction of DNA from bovine tissue samples was developed and used in a PCR designed for the diagnosis of tuberculosis. Tissues from 81 cattle from tuberculosis-infected herds (group 1) and 19 cattle from tuberculosis-free herds (group 2) were tested in this PCR, and the results were compared with those of conventional culture. The PCR assay detected 71.4% of the culture-positive animals from group 1. Tissues from all animals in group 2 were negative in the PCR assay and by culture. The described method could be used as a rapid screening technique which would be complementary to culture of tissue specimens for the routine diagnosis of bovine tuberculosis. The PCR technique is much faster than culture and reduces the time for diagnosis from several months to 2 days. It also provides for the detection of M. bovis when rapidly growing Mycobacterium spp. are present in the sample and may be able to detect the presence of M. bovis in samples even when organisms have become nonviable.

A survey of patulin in 100 samples of commercial apple juice and 12 samples of apple food for children collected a t stores in Madrid (Spain) during 1992 was conducted. Patulin levels were determined by a dialysis diphasic membrane procedure using reversed-phase high-pressure liquid chromatography as analytical method. The results obtained in apple juice were as follows: patulin was detected in 82% of samples; 75% of the analyzed apple juice contained less than 10 p g L , and the maximum concentration found was 170 p a ; children's apple food samples were free of patulin. It is suggested that patulin should be used as a quality indicator of the apples employed in the elaboration of food and drink.