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Lactococcus lactis subsp. lactis bv. diacetylactis strains are often used as starter cultures by the dairy industry due to their production of acetoin and diacetyl, important substances that add buttery flavor notes in dairy products. Twenty-three L. lactis subsp. lactis isolates were obtained from dairy products (milk and cheese) and dairy farms (silage), identified at a biovar level, fingerprinted by rep-PCR and characterized for some technological features. Fifteen isolates presented molecular and phenotypical (diacetyl and citrate) characteristics coherent with L. lactis subsp. lactis bv. diacetylactis and rep-PCR allowed the identification of 12 distinct profiles (minimum similarity of 90%). Based on technological features, only two isolates were not able to coagulate skim milk and 10 were able to produce proteases. All isolates were able to acidify skim milk: two isolates, in special, presented high acidifying ability due to their ability in reducing more than two pH units after 24 h. All isolates were also able to grow at different NaCl concentrations (0 to 10%, w/v), and isolates obtained from peanut and grass silages presented the highest NaCl tolerance (10%, w/v). These results indicate that the L. lactis subsp. lactis bv. diacetylactis isolates presented interesting technological features for potential application in fermented foods production. Despite presenting promising technological features, the isolates must be assessed according to their safety before being considered as starter cultures.

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O gênero Weissella é composto por bactérias classificadas como Gram-positivas, catalase negativas, não formadoras de esporos, morfologia cocóide ou bacilos curtos. Pertencem ao grupo das bactérias lácticas (BAL), principalmente pela produção de ácido láctico a partir da fermentação de carboidratos. As espécies de Weissella estão distribuídas em diferentes habitats, como solos, ordenhadeiras, cana-de-açúcar e algumas cepas com características tecnológicas interessantes podem ser isoladas de alimentos fermentados, como queijos de leite cru, vegetais fermentados e leite fermentado. Do ponto de vista da tecnologia de alimentos, algumas cepas apresentam potencial na produção de exopolissacarídeos, oligossacarídeos não digeríveis, que está além de seu potencial probiótico. Portanto, as bactérias pertencentes ao gênero Weissella podem ter grande importância tecnológica, estando também envolvidas no controle de doenças de origem alimentar pela produção de bacteriocinas e peróxido de hidrogênio. Este gênero possui grande potencial para uso na indústria alimentícia.

Passion fruit (Passiflora cincinnata Mast.) is a native fruit from the Caatinga, a typical ecoregion in northeastern Brazil, and it has potential for use by the food and pharmaceutical industries. In this study, we characterized the antimicrobial activity of P. cincinnata and its application in the production of coalho cheese, a traditional Brazilian product. Aqueous extract of P. cincinnata exhibited high inhibitory activity against Listeria spp. (n = 4, reference strains), Staphylococcus aureus (n = 3, reference strains), and multidrug-resistant Staph. aureus (n = 8), and low inhibitory activity against lactic acid bacteria (LAB, n = 3, reference strains). Based on these results, we produced coalho cheese using goat milk with and without (control) passion fruit. Cheeses were stored at 10°C for 14 d and populations of mesophilic aerobes, Staph. aureus, and presumptive LAB were monitored at d 1, 7 and 14. The passion fruit cheese had lower counts of mesophilic aerobes, Staph. aureus (after 7 and 14 d), and presumptive LAB (after 14 d) than the control cheese. Adding ground passion fruit contributed to a reduction of Staph. aureus counts in goat cheese, although these differences were not significant. These results indicated the inhibitory potential of passion fruit and its potential use for controlling microbial populations in a cheese model; further studies are needed to characterize the active molecules that are responsible for such activity.