Unfolding microbiota and volatile organic compounds of Portuguese Painho de Porco Preto fermented sausages

In the present study, bacterial and fungal diversity, as well as volatile profiles, of ready-to-eat Portuguese Painho de Porco Preto fermented sausages manufactured by two artisanal producers in the districts of Beja (producer A) and Evora (producer B) were studied. To this end, different selective growth media and a metataxonomic analysis were combined with Headspace Solid-Phase Microextraction-Gas Chromatography/Mass Spectrometry (HS- SPME-GC/MS) analysis. The results of the microbiological viable counts revealed active microbial populations of lactic acid bacteria (up to 8 Log cfu g-1), coagulase negative cocci (up to 6 Log cfu g-1), and eumycetes (up to 6 Log cfu g-1). Bacterial populations were characterized by high relative frequencies of Latilactobacillus sakei (up to 72%), together with Weissella and Staphylococcus equorum. The mycobiota was mainly dominated by Debar- yomyces hansenii (up to 55% of the relative frequency) and Kurtzmaniella zeylanoides (up to 24% of the relative frequency). Unexpected species as Wickerhamomyces subpelliculosus and Zygosaccharomyces rouxii were also detected. HS-SPME-GC/MS analysis allowed to identify a complex volatile profile, showing 159 volatile organic compounds (VOCs). VOCs belonged to twelve classes, such as aldehydes, ketones and lactones, esters and ace- tates, alcohols, terpenoids, sulfur compounds, aliphatic hydrocarbons, aromatic hydrocarbons, nitrogen com- pounds, acids, furans and pyrans, and phenols. The analysis of VOCs composition provided evidence that samples from the two producers (A and B) were different, as confirmed by the Principal Component Analysis. Hence, it is likely that the raw materials used, as well as variations related with the empirical practice of the butchers, strongly influenced the final product. The results obtained in the present study represent a further advancement in the knowledge on the biodiversity and VOCs composition of Portuguese fermented sausages. To better un- derstand the interactions occurring between the autochthonous microorganisms and the meat batter in the Painho de Porco Preto fermented sausage, microbial and VOCs dynamics must be further deepened throughout the production process.