Abstract:
This study was concerned with a chemical and microbiological characterisation of
cheese made using milk from Algarvian goat breed. Seasonal variation of the
microbiota and the gross chemical composition of the raw and boiled milk and cheese
during the lactation period were studied. The cardoon microbiota and the variation of
microbiota during ripening were studied also. The lactic acid bacteria (LAB) were
isolated, identified to genus level and their technological properties such as
bacteriocin production, acidifying capacity, proteolysis and lipolysis were studied.
The results showed that boiling milk does not represent a cause of variation in its
gross composition and almost all the gross components of the milk and cheese register
no variation during the studied period, except for fat, which increased until the middle
of the lactation period and decreased after that.
In cardoon, the microorganisms that are able to produce spores are the most
important, thus analysis of yeasts and moulds was carried out which allowed the
arrangement of the tested samples into three groups. Most of the identified moulds
from the cardoon samples are from the genus Aspergillus.
During the study period, differences in the microbiota of the raw milk were not
observed, with Lactococcus and Lactobacillus being the prevalent groups. All the
tested microorganisms increased approximately by two orders of magnitude from
milk to cheese.
Lactobacillus was the predominant group during the maturation period. Total
coliforms tended to diminish in the early stages of ripening.
Isolates from Lactobacillus and Pediococcus genera showed fast acidification
capacity, which could be an indicator of good potential for their use as starter bacteria.
Some Lactobacillus produced bacteriocin which can contribute to the removal of
other bacteria. Aerococcus, Leuconostoc and Lactobacillus presented high proteolytic
activity, which mean they could be used as adjunct cultures to improve proteolysis.
Only one isolate (Pediococcus) showed lipolytic activity. In conclusion, by their
technological characteristics some isolates could be selected as starter cultures,
however, further research of their pathogenesis is necessary before using them in pilot
plant production.
