Effects of the replacement of nitrates/nitrites in salami by plant extracts on colon microbiota

Salami is a cured sausage consisting of fermented and air-dried meat obtained from a mixture of meat and fat with spices and other ingredients. Excessive processed meat consumption is negatively considered because of its high fat and salt contents and few bioactive molecules. Notwithstanding, salami is largely consumed, and there is a strong interest to produce better and healthier products by substituting nitrites and nitrates with natural extracts. This work produced four different salami, two controls including nitrates and two alternative preparations where nitrates were substituted with plant extract and ascorbic acid. The products were in vitro digested with the INFOGEST protocol to simulate the oro-gastro-duodenal phase and in vitro fermented with MICODE model to simulate the colon phase. Samples were analyzed by microbiomics and metabolomics approaches to study the changes in bacterial populations and in metabolites production. The results showed that the clean-label formulations promote a general eubiosis of the intestinal microbiota, including favorable F/B ratio, the proliferation of beneficial microbial taxa (Bifidobacteriaceae), and reduction of negative microbial populations (Enterobacteriaceae). Volatilome analysis highlighted a marked production of beneficial molecules, including acetate, propionate and butyrate, and a reduction in host negative molecules such as phenol and p-cresol. Our results tell that the plant extracts could be used to replace nitrates, because the features obtained are comparable to those of controls. This work could represent an encouraging starting point for the processed meat industry for the development of clean-label formulations aimed at reducing the negative impact of these products on consumers.