Leuconostoc: su rol en la producción de defectos gasógenos en quesos (Póster)

GUGLIELMOTTI, D.M.; REINHEIMER, J.A.; QUIBERONI, A.

Córdoba, Argentina

Congreso; III Congreso Internacional de Ciencia y Tecnología de los Alimentos; 2009

Ministerio de Ciencia y Tecnología de la provincia de Córdoba

 Leuconostoc is normally associated to vegetables, wine, milk and its derivatives. Its ability to produce aroma compounds (dacetyl and acetoin) from citrate is very important for the production of butter and some type of cheeses. Between 2000 and 2008, samples of soft and semi-hard cheeses with evident blowing defects from 14 industrial manufactures have been analyzed. Cheese samples showed an abnormal presence of small ‘eyes’, although aroma and flavor were generally normal. Microbial counts covered a wide range of possible gas-producing microorganisms. Tubes of MRS broth (containing Dürham tubes) were used (limit dilutions) to enumerate gas-producing bacteria. Counts on agarized media included yeasts (yeasts extract dextrose chloramphenicol agar, YGC), coliforms (violet red bile agar, ABRV), and lactic microflora (MRS and skim milk agar). Leuconostoc strains were isolated from plate counts colonies or from limit dilutions. The strain identification was carried out by colony and cell morphology observation, catalase test, Gram coloration, homo/heterofermentation and sugar fermentation patterns. Among Leuconostoc genera, Ln. mesenteroides was found in high number (107-108 CFU/ml). Surprisingly, this study showed a clear preponderance of Leuconostoc genera as the major responsible of cheese-blowing defects.