Technological properties of Enterococcus faecium isolated from ewe’s milk and cheese with importance for flavour development

ABEIJÓN MC., MB KATZ, RB MEDINA, S GONZÁLEZ

CANADIAN JOURNAL OF MICROBIOLOGY

NRC Reaerach Press

Lugar: Toronto - Canadá; Año: 2006 vol. 52 p. 237 - 245

0008-4166

Among eight Enterococcus faecium strains isolated from ewe’s milk and artisanal cheese from northwest Argentina, acidifying, proteolytic activities, diacetyl production, citrate utilization and esterase-lipase activities were evaluated. The API ZYM test showed absence of proteases, presence of high amounts of peptidases and low esterase-lipase activities. The strains exhibited low milk acidifying ability, low extracellular proteolytic activity and produced diacetyl in milk.  The strains were found to be good utilisers of citrate as sole energy source.  The E. faecium strains tested in this work hydrolysed a-naphtyl derivatives of fatty acids in this order: C3>C6>C4>C8>C2. Post-electrophoretic detection of esterase activities revealed that the esterolytic system of enterococci is rather complex. For all the strains, activity was detected up to a-naphthyl-caproate.  E. faecium OvQ 426, OvL 214 and OvL 242 presented four active esterolytic bands. E. faecium OvL 194 showed two bands of esterase activity.  In the other strains a maximum of three bands was observed.  All the strains hydrolysed tributiryn and cell free extract of strains OvQ 157, OvQ 167, OvQ 178, OvQ 426, OvL 241 and OvL 254 hydrolysed fat milk. The Enterococcus faecium strains isolated from ewe’s milk and artisanal cheese from northwest Argentina presented the metabolic potential to contribute in the development of cheese flavour.