Ml. Parker et al., MICROSTRUCTURE AND DISTRIBUTION OF MICROORGANISMS WITHIN MATURE SERRACHEESE, Journal of applied microbiology, 84(4), 1998, pp. 523-530
The distribution of micro-organisms in mature Serra, a traditional Por
tuguese cheese made from unpasteurised ewes' milk without added starte
r culture, was examined by light microscopy and electron microscopy. F
our populations of micro-organisms were recognized according to their
position within the cheese: (i) those present as apparently axenic col
onies within the curd matrix; (ii) bacteria growing along curd junctio
ns; (iii) yeasts and bacteria present in the smear on the surface of t
he cheese and (iv) bacteria found in cracks which penetrated the outer
part of the cheese from the rind. Two types of crystals were observed
, together with contaminants of vegetable origin and somatic cells ori
ginating from the milk.