Listeria monocytogenes sensitivity to antimicrobial treatments depends on cell origin

In this study we investigated how cell origin could affect the efficacy of an antimicrobial treatment (mild heating combined with terpenoids) in Listeria monocytogenes Scott A, considering cells from: 1. single colony, 2. glycerol stock, 3. cold adapted culture, and 4. fresh culture in stationary phase. After treatment, culturability on BHI medium and viability assessed by flow cytometry were evaluated. Our results showed that the cell origin significantly impacted viability and culturability of L. monocytogenes towards antimicrobial treatment. The mild heat treatment combined or not with terpenoids mainly affected culturability rather than viability, although the culturability of cells from single colony was less impacted. Therefore, to mimic the worst scenario, these latter were selected to contaminate Gorgonzola rind and roast beef slices and we evaluated the ability of L. monocytogenes cells to recover their culturability (on ALOA agar medium) and to growth on the food matrix stored at 4 °C for 7 days. Our results suggest that only Gorgonzola rind allowed a partial recovery of the culturability of cells previously heated in presence or not of terpens. In conclusion, we found a connection between the cell history and sensitivity toward an antimicrobial treatment, underlying the importance to standardize the experimental procedures (starting from the cells to be used in the assay) in the assessment of cell sensitivity to a specific treatment. Finally, our study clearly indicated that VBNC cells can resuscitate under favorable conditions on a food matrix, becoming a threat for consumer’s health

Effects of Starter Cultures and Type of Casings on the Microbial Features and Volatile Profile of Fermented Sausages

In the literature, the effect of the type of casing on fermented sausages is quite unexplored, while several studies are focused on the impact of starter cultures. Therefore, this paper studied the effect of three commercial starter cultures and two casings (natural or collagen) on Italian fermented sausages. Physico-chemical parameters (aw, pH, weight loss), microbiota, aroma profile and sensory analysis were evaluated. Results showed that collagen casings promoted a higher reduction of pH and weight loss. Concerning the microbiota, samples with natural casing had higher counts of lactic acid bacteria, while yeast proliferation was promoted in those with collagen. Regardless of the starters and casings applied, levels of enterococci and Enterobacteriaceae were low (≤2 log CFU/g). The aroma profile was significantly affected by casing: despite the starter applied, the presence of collagen casing favoured acid accumulation (mainly acetate and butanoate) and reduction of ketones. Sensory analysis highlighted significant differences only for odour, colour intensity and sourness. The differences observed suggest that collagen casings may provide a greater availability of oxygen. Overall, casings rather than starter cultures impact the microbial and sensorial features of fermented sausages

Microbial Spoilage of Traditional Goose Sausages Produced in a Northern Region of Italy

Recently, during the ripening of goose sausage, a defect consisting of ammonia and vinegar smell was noticed. The producer of the craft facility, located in Lombardia, a Northern region of Italy, asked us to identify the cause of that defect. Therefore, this study aimed to identify the potential responsible agents for the spoilage of this lot of goose sausages. Spoilage was first detected by sensory analysis using the "needle probing" technique; however, the spoiled sausages were not marketable due to the high ammonia and vinegar smell. The added starter culture did not limit or inhibit the spoilage microorganisms, which were represented by Levilactobacillus brevis, the predominant species, and by Enterococcus faecalis and E. faecium. These microorganisms grew during ripening and produced a large amount of biogenic amines, which could represent a risk for consumers. Furthermore, Lev. brevis, being a heterofermentative lactic acid bacteria (LAB), also produced ethanol, acetic acid, and a variation in the sausage colour. The production of biogenic amines was confirmed in vitro. Furthermore, as observed in a previous study, the second cause of spoilage can be attributed to moulds which grew during ripening; both the isolated strains, Penicillium nalgiovense, added as a starter culture, and P. lanosocoeruleum, present as an environmental contaminant, grew between the meat and casing, producing a large amount of total volatile nitrogen, responsible for the ammonia smell perceived in the ripening area and in the sausages. This is the first description of Levilactobacillus brevis predominance in spoiled goose sausage

Insights into the Metabolomic Diversity of Latilactobacillus sakei

: Latilactobacillus sakei (L. sakei), widely used as a starter culture in fermented sausages, is a species adapted to meat environments. Its ability to survive for a long time in such products is due to the exploitation of different metabolic pathways to gain energy (hexose and pentose sugar fermentation, amino acids catabolism, etc.). Since L. sakei demonstrates high phenotypic and metabolic strain biodiversity, in this work, a metabolomic approach was used to compare five strains of different origins. They were cultivated in a defined medium with glucose or ribose at two concentrations, and analyzed through nuclear magnetic resonance (1H-NMR) spectroscopy to monitor amino acid consumptions and accumulation of organic acids and aroma compounds. The results showed that all the strains were able to use arginine, especially when cultivated with ribose, while serine was consumed mainly in the presence of glucose. Aroma compounds (i.e., diacetyl and acetoin) were mainly accumulated in samples with ribose. These aspects are relevant for starter cultures selection, to confer specific features to fermented sausages, and to optimize the fermentations. Moreover, the use of 1H-NMR allowed the fast identification of different classes of compounds (without derivatization or extraction procedures), providing a powerful tool to increase the knowledge of the metabolic diversity of L. sakei

Survival, growth, and biogenic amine production of Enterococcus faecium FC12 in response to extracts and essential oils of Rubus fruticosus and Juniperus oxycedrus

Enterococci are lactic acid bacteria (LAB) usually found as food contaminants in fermented products such as cheeses and fermented sausages. Due to their antibiotic resistance, the presence of virulence factors, and the ability to produce biogenic amines (BAs), the determination of these bacteria is crucial to assure food quality and safety. BAs production and consequent accumulation in foods can cause toxicological eects on human health. Plant phenolic compounds are promising alternatives to chemical preservatives and reflect consumers’ demand for “green” solutions. In this study, the antimicrobial eect of blackberry (Rubus fruticosus) leaves and prickly juniper (Juniperus oxycedrus) needles, both as phenolic extracts (PE) and essential oils (EO), were evaluated against Enterococcus faecium FC12, a known tyramine-producing strai

Sul/Sudoeste mineiro na reversão da migração interestadual em Minas Gerais

From information on the migration of data-sets of Demographic Census of 1991 and 2000 this study examines migration flows in interstate mesoregion south/southwest of Minas Gerais, according to the micro regions of origin and destination quinquennium in 1986/1991 and 1995 / 2000. The data show a reversal of balances migration, from negative to positive in mesoregion South/South West in the 1995/2000 compared to 1986/1991. These changes were decisive in reversing the role of Minas Gerais in the national migration scenario. The results suggest that the space decentralization process of the population and some economic activities that have occurred in the most dynamic regions of the country, combined with geographical location, not only turned into strategic advantages for the economy of mesoregion South / South West, but also elevated their power of attraction and retention population.Resumo Este trabalho analisa, a partir de informações referentes à migração de data-fixa dos Censos Demográficos de 1991 e 2000, os fluxos migratórios interestaduais na mesorregião Sul/Sudoeste de Minas Gerais, segundo as microrregiões de origem e destino nos qüinqüênios 1986/1991 e 1995/2000. Os dados revelam uma reversão dos saldos migratórios, de negativo para positivo, na mesorregião Sul/Sudoeste no período de 1995/2000 comparativamente ao qüinqüênio 1986/1991. Estas mudanças foram decisivas na reversão do papel de Minas Gerais no cenário migratório nacional. Os resultados sugerem que o processo de desconcentração espacial da população e de algumas atividades econômicas que vem ocorrendo nas regiões mais dinâmicas do país, aliada a localização geográfica, não só se transformou em vantagens estratégicas para a economia da mesorregião Sul/Sudoeste, mas também eleva seus poderes de retenção e atração populacional. Palavras-chave: Migração interestadual; Mesorregião, Sul/Sudoeste; Minas Gerais. South / South West miner in the reversal of interstate migration in Minas Gerais Abstract: This study examines, from informations about the migration of data-sets of Demographic Census of 1991 and 2000, migration flows in interstate mesoregion south / southwest of Minas Gerais, according to the microregions of origin and destination quinquennium in 1986/1991 and 1995 / 2000. The date shows a reversal of balances migration, from negative to positive in mesoregion South / South West in the 1995/2000 compared to 1986/1991. These changes were decisive in reversing the role of Minas Gerais in the national scenario of migration. The results suggest that the process of space decentralize of the population and some economic activities that has occurred in the most dynamic regions of the country, combined with geographical location, not only turned into strategic advantages for the economy of mesoregion South / South West, but also elevates his powers of attraction and retention population. Key-words: Interstate migration; Mesoregion, South/South West; Minas Gerais

Squamous cell carcinoma "transformation" concurrent with secondary T790M mutation in resistant EGFR-mutated adenocarcinomas

Publisher Copyright: © 2016 International Association for the Study of Lung Cancer. Published by Elsevier Inc.The authors report two cases of epidermal growth factor receptor gene (EGFR)-mutant stage IV lung adenocarcinomas developing immunohistochemically proven squamous cell carcinoma (SCC) "transformation" concurrently with T790M EGFR mutation, leading to acquired resistance to EGFR inhibitors. Moreover, the histologic change of EGFR-mutant lung adenocarcinoma into SCC has been recently reported in literature. The histological transformation to SCC appears as a novel mechanism of acquired EGFR TKI resistance in EGFR-mutated adenocarcinomas and it may be challenging for treatment.publishersversionPeer reviewe

Use of two autochthonous bacteriocinogenic strains as starter cultures in the production of salchichónes, a type of Spanish fermented sausages

In this work, two autochthonous LAB strains (Lactiplantibacillus paraplantarum BPF2 and Pediococcus acidilactici ST6), isolated from spontaneously fermented sausages produced in Spain, were tested to produce Spanish fermented sausages (salchichón) in pilot plants, due to their promising technological and anti-listerial activity. These products were compared with a sample obtained with a commercial starter (RAP) and a spontaneously fermented control sample. Physico-chemical parameters, microbial counts, metagenomic analysis, biogenic amines content and organoleptic profile of the obtained samples were studied to assess the performances of the native starters. In fact, traditional and artisanal products obtained through spontaneous fermentations can represent an important biodiversity reservoir of strains to be exploited as new potential starter cultures, to improve the safety, quality and local differentiation of traditional products. The data underlined that ST6 strain resulted in a final lower percentage if compared with the other LAB used as starter cultures. The use of starters reduced the BA concentration observed in the sausages obtained with spontaneous fermentation and the BPF2 and ST6 strains were able to decrease the level of products rancidity. Moreover, a challenge test against L. monocytogenes were performed. The data confirmed the effectiveness in the inhibition of L. monocytogenes by the two bacteriocinogenic strains tested, with respect to RAP and control samples, highlighting their ability to produce bacteriocins in real food systems. This work demonstrated the promising application in meat industry of these autochthonous strains as starter cultures to improve sensory differentiation and recognizability of typical fermented sausages

O norte e nordeste de Minas Gerais no contexto das migrações contemporâneas brasileiras

This study analyses information about the migration of data-sets of the Demographic Census of 1991 and 2000, migration flows in interstate mesoregion south / southwest of Minas Gerais, according to the microregions of origin and destination. The data show a reversal of balances migration, from negative to positive in mesoregion South / South West in the 1995/2000 period compared to 1986/1991. These changes were decisive in reversing the role of Minas Gerais in the national scenario of migration. The results suggest that the process of space decentralization of population and some economic activities that have occurred in the most dynamic regions of the country, combined with geographical location, not only turned into strategic advantages for the economy of mesoregion South / South West, but also elevated its powers of attraction and retention of population.Este trabalho tem como objetivo analisar o comportamento recente da migração nas mesorregiões históricas de perdas populacionais, complementadas pelas respectivas microrregiões selecionadas, levando-se em conta a origem e destino dos migrantes de Minas Gerais. Os resultados apontam que há manutenção e redução das emigrações nas mesorregiões em estudo. No âmbito da migração intraestadual, percebe-se a manutenção e intensificação nas perdas de população. As mudanças de modalidade migratória podem estar aliadas às novas áreas de oportunidade que o Estado vem oferecendo, novas estratégias de migração e o fortalecimento e ampliação de redes sociais entre os migrantes no interior do Estado, as quais estão calcadas na interação dos atores distribuídos em suas respectivas estruturas sociais

Identification, safety and technological characteristics of Weissella strains from traditional Southwestern Algerian kaddid

Kaddid is a dry-fermented meat product traditionally produced in North Africa by spontaneous fermentation. As a reservoir of natural biodiversity, the identification and relevant traits of lactic acid bacteria (LAB) were carried out from South-western Algeria homemade samples. After a preliminary physiological and biochemical screening, 19 presumptive LAB isolates were selected on the basis of antimicrobial compounds production. The isolates were identified by 16S rRNA gene sequencing as Weissella cibaria, W. confusa, W. paramesenteroides, Pediococcusacidilactici, and Enterococcus hirae. As predominant, the safety and technological characterization of Weissella strains were performed. The production of antimicrobial and antifungal compounds was observed, while neither H2S, biogenic amines nor hemolytic activity were detected; antibiotic resistance was exhibited, however several strains were more susceptible to assayed antibiotics. Technological characterization of Weissella strains showed high acidification rates even in the presence of up to 10 % NaCl, autolytic and proteolytic capacity however, no EPS production and lipolytic activity were observed. Strains characterization led to the selection of W. cibaria BK2, W. confusa BK6 and BK11 as well as W. paramesenteroides BK8 to be considered as possible candidates for use as starter culture for kaddid fermentation to improve and standardize this traditional meat product