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Advisor(s)
Abstract(s)
Serrana cheese is a law protected product susceptible of transmitting Stapltylococcus aureus since it is made of raw milk. This bacterium development can only be prevented by refrigeration temperatures and maturation.
S. aureus survival in Serrana goat cheese was tested because it is a common source of mastitis in goats. A native strain isolated (FCT Project, POCTUI 999/CVT/3482) from a local goat herd (Trás-os-Montes Portuguese Province) was inoculated in two cheese batches, one of them made with pasteurized milk.
Immediately after cheese production and thereafter weekly for four weeks S. aureus was counted and pH and aw were assessed. Maturation temperature ranged from 5 to 12°C.
According to bibliography pH and aw never meet critical values able to prevent bacterial development. However, ripening temperature is a well-known limiting factor, especially if associate with pH and aw values diverting from optimum.
By the end of this study S. aureus concentrations were identical to initial values (3 x 104 cfu/g). This result was unexpected since S. aureus has been considered as a minor risk in cheese. Likely this native strain presented an unusual endurance to cheese ripening conditions becoming a possible public health risk. Its future biochemistry and molecular characterizations are expected to elucidate on this endurance ability.
Description
Keywords
Queijo Serrana
Citation
Mendonça, Álvaro; Santos, Sandra; Valentim, Ramiro; Correia, Teresa (2003). Staphylococcus aureus survival during maturation of Serrana goat cheese. In National Congress of Microbiology – MICRO’2003. Tomar
Publisher
Sociedade Portuguesa de Microbiologia