Evaluation of high-pressure as a non-thermal pasteurisation technology to render Serra cheese manufactured from raw ewe milk microbiologically safe

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Effect of high pressure pre-treatment on raw ewes’ milk and on subsequently produced cheese throughout ripening

Publication . Inácio, Rita S.; Pinto, Carlos A.; Saraiva, Jorge A.; Gomes, Ana M. P.

BACKGROUND: Raw ewe’s milk, used to manufacture Serra da Estrela Protected Designation of Origin (PDO) cheese, was pre-treated by high pressure processing (HPP), using previously optimized conditions (121 MPa/30 min), in order to evaluate its effect on milk technological properties for subsequent cheese production, namely the impact on resulting curd, whey, and cheese throughout ripening. RESULTS: The cheese yield increase 10.4% as a result of milk pre-treated by HPP, which also yielded inactivation of beneficial microbial groups. After 60 days of ripening, both treated and control cheeses showed neither significant differences (P ≥ 0.05) in quantified microbial load nor in basic physicochemical quality parameters. CONCLUSION: HPP seems to be a promising non-thermal treatment for ewes’ milk to inactivate contaminant bacteria yet with no negative effect on lactic acid bacteria, which are very important for the unique characteristics of Serra da Estrela cheese.

2021-06-01Journal article

Open access

Serra da Estrela cheese: a review

Publication . Inácio, Rita S.; Gomes, Ana M. P.; Saraiva, Jorge A.

Serra da Estrela cheese with Protected designation of origin certification is manufactured using only raw ewes’ milk, salt, and a crude plant rennet, from the dried flowers of Cynara cardunculus L., resulting in a cheese with peculiar sensorial features (without the addition of starters or additives) that has existed over many centuries. More than 40 scientific reports concerning this cheese have been published since 1992. The composition and microbial profile have revealed certain variations among the literature. During the ripening of Serra da Estrela cheese, biochemical changes occur, which are reflected in its particular flavor and texture characteristics. An intense proteolytic activity takes place along ripening and storage, and volatiles are associated with typical flavor like “butter‐cream texture.” Innovation concerning Serra da Estrela cheese has been performed within milk quality, manufacture process, and in ripened cheese.

2020Journal article

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