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.

Helados de elaboracion artesanal y semiindustrial. Incidencia de Staphylococcus aureus y enterotoxigenicidad. / Craft or semi-industrial ice cream. Occurence of Staphylococous aureus and enterogenicity

En 7 heladerias de elaboracion artesanal y semiindustrial se retiraron 67 muestras de helados a base de crema de leche y de agua. El 43,3% de las muestras fueron positivas para la investigacion de Staphylococcus aureus en 1 g, el 88% de las mismas presentaron menos de 10 St. aureus por g, 10,5% entre 10 y 100 y 1,5% entre 101 y 1.000.A 29 cepas se les determino la enterotoxigenicidad, la respuesta a diversas pruebas bioquimicas y la sensibilidad a antibioticos. El 21% de las cepas resultaron enterotoxigenicas (4 produjeron toxina A, 1 toxina B y 1 toxinas A y D). No se hallo diferencia en las pruebas bioquimicas realizadas (produccion de catalasa, coagulasas, termonucleasas, fermentacion de glucosa y manitol, hidrolisis de gelatina y caseina, produccion de pigmentos y hemolisinas) entre las cepas toxigenicas y no toxigenicas. Todas las cepas presentaron una amplia sensibilidad frente a los antibioticos. Como resultado del presente estudio se propone incorporar al articulo 1075 del Codigo Alimentario Argentino el limite de 100 Staphylococcus aureus por g en helados a base de crema y de agua