Effect of dairy farm and milk refrigeration on microbiological and microstructural characteristics of matured Serra da Estrela cheese

Abstract

This work was aimed at enumerating the viable microorganisms in ripened Serra da Estrela cheeses, manufactured from both refrigerated and non-refrigerated milk, in various dairies located throughout the demarcated region. Scanning electron microscopy was used to analyze the microstructure, and thus aid in understanding possible differences in their microbiological profile. The cheeses were allowed to ripen under controlled conditions, and sampled at 60, 90, 120, 150 and 180 d following manufacture. Viable numbers of lactic acid bacteria, staphylococci, Enterobacteriaceae and yeasts were obtained following standard plate counting on a number of selective media. Lactococcus was the most abundant genus (above 10 8 cfu g À1 of cheese) up to 120 d of ripening. No significant microstructural differences were observed in cheeses manufactured in different dairies over the ripening process. However, microstructural differences were apparent between cheeses manufactured with refrigerated versus non-refrigerated milk. r

PTR‐TOF‐MS and data‐mining methods for rapid characterisation of agro‐industrial samples: influence of milk storage conditions on the volatile compounds profile of Trentingrana cheese

“…1c exemplifies the possibility of the simultaneous quantification of isobaric compounds, even at very different concentrations, as is the case for ethanol and formic acid (both at nominal mass of 47 Th) and demonstrates also the possibility to account for a contribution of an instrumental background at m/z = 47.024. Methanol is also detected at nominal mass 33 and the TOF allows the separation of the contribution of isobaric 18 …”

“…[14] Trentigrana is produced from partly skimmed raw cow's milk acidified with a mixture of Lactobacillus and coagulated by the addition of bovine rennet but, having a more restrictive protocol as compared with Grana cheese, the use of lysozyme and silage for the cow's feeding are not allowed. [15] At the 18 cheese factories belonging to the Trentingrana consortium, the milk used comes from a double milk collection: the full fat milk of the evening milking is delivered to the cheese factory in churns (traditional method) or in tanks at controlled temperature (18 • C) and undergoes a natural creaming process (or gravity separation [16] ) in large vats. After skimming the evening milk is added to the milk of the morning milking and used to produce cheese according to the standard cheese-making procedure of the Trentigrana.…”

“…The effects of the different dairy maturation of milk on physico-chemical characteristics, on rennet-coagulation aptitude and on rheological properties have been thoroughly studied for the case of Parmigiano Reggiano by Malacarne et al [17] Despite the number of studies about the influence of storage on the milk quality, little is known about the relationship between milk storage modalities and the quality of the cheese produced. Tavoria and Malcata [18] showed that cheese manufactured with refrigerated or non-refrigerated milk are different in terms of micro-structural characteristics, but no studies have been published on the effect on the final volatile compounds profile of ripened cheese.…”

Chestnut and lemon balm based ingredients as natural preserving agents of the nutritional profile in matured “Serra da Estrela” cheese

“…It is only manufactured with raw ewe's milk, salt and milk thistle flower for coagulation, and it is preferentially consumed as a soft cheese, with an average maturation of 1 month, although some consumers prefer to consume it as a hard cheese after at least 6 months of storage. Despite some published studies on the ''Serra da Estrela" cheese, that focus mainly on the microbial flora in the cheese, as well as the changes in some nutrients during ripening (Dahl, Tavaria, & Malcata, 2000;Macedo, Tavares, & Malcata, 2004;Partidário, Barbosa, & Boas, 1998;Tavaria, Franco, Carballo, & Malcata, 2003;Tavaria, Reis, & Malcata, 2006), the present work evaluates the effects of natural additives (chestnut flowers, lemon balm dry material and their decoctions) on the nutritional properties of cheese during its maturation.…”

The effect of milk collection and storage conditions on the final quality of Trentingrana cheese: Sensory and instrumental evaluation

“…Dahl, Tavaria, and Malcata (2000) reported that cheeses produced from refrigerated and non-refrigerated raw sheep milk present differences in microbiological profiles during ageing and in volatile patterns at the end of six months of ripening. The same research group (Tavaria, Reis, & Malcata, 2006) reported that cheeses manufactured with refrigerated milk were different in their micro-structural characteristics. Even if chemical composition, rheological behaviour and sensory attributes were closely associated with cheese micro-structure, the effect of cold-induced changes in cheeses on the perceptible sensory quality is still undemonstrated.…”