Preparación de reactivos para la detección de proteínas de diferentes especies animales por inmunodifusión / [Preparation of reactants for the detection of proteins from different animal species by immunodiffusion]

Qualitative identification of fresh ground meat samples of beef, sheep, pork, horse and rabbit has been made by the double agar gel diffusion test (method of Ouchterlony) and by immunoelectrophoresis. The reagents used were: 1) Antigens: saline meat extracts from different animal species, saline meat mixture extracts and whole sera from the different animal species. Meat extracts and sera were controlled by electrophoresis and the amounts of protein were estimated by the method of Lowry; 2) Antibodies: multivalent antisera anti-bovine, anti-ovine, anti-porcine and anti-equine, were obtained by immunization of rabbits with an emulsion of 1 vol of whole serum and 1 vol of Freund complete adjuvant; anti-rabbit serum was obtained by immunization of rats; antisera were controlled by the double agar gel diffusion test and by immunoelectrophoresis. To remove cross-reacting antibodies, when it was necessary, antisera were adsorbed.

Helados de elaboración industrial. Incidencia de Staphylococcus aureus y enterotoxigenicidad / [Ice cream of industrial manufacture. Incidence of Staphylococcus aureus and enterotoxigenicity]

A total of 70 samples of ice-creams, milk, milk cream and water or fruit based were obtained from 7 different industrial producers. Of these samples, 14.3

were positive for Staphylococcus aureus in 1 g: 97.2

showed less than 10 St. aureus in 1 g, 1.4

between 101-1,000 and 1.4

between 1,001-10,000. In 21 strains enterotoxigenicity, was investigated, as well as the response to different biochemical tests and the susceptibility to antibiotics: 9.5

of the strains were toxigenic (2 strains), 1 produced enterotoxin A and 1 enterotoxin B. There was no difference between toxigenic and nontoxigenic strains when the 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 a wide susceptibility when they were tested with different antibiotics. Our results confirm the limit introduced to the article 1078 of the Argentine Food Code for ice-creams of industrial production (100 per g) but there is no specification of the count method to be used.