Occurrence and growth of Listeria monocytogenes in packaged raw milk

The increased availability of packaged raw drinking milk necessitates the investigation of the occurrence and growth of Listeria monocytogenes in raw milk during distribution and storage. The occurrence of L. monocytogenes in 105 retailed raw milk bottles, 115 bulk tank milk samples, 23 in-line milk filter socks and in 50 environmental samples collected from an on-farm dairy establishment were investigated. Growth of inoculated low-level L. monocytogenes contamination was also investigated in two types of raw milk packaging, namely in 1-litre plastic bottles and 3-litre bag-in-boxes, both stored at three different storage temperatures of 6, 8 and 10 degrees C. The occurrence of L. monocytogenes was higher (4.8%) in bottled raw milk stored until the use-by-date of the package compared to fresh bulk tank milk (1.7%). L. monocytogenes counts were 5 13 CFU/ml in bottled raw milk and 5 1 CFU/ml in bulk tank milk. L. monocytogenes was not detected in the packaging facility, but occurred very frequently (39%) in the milk filter socks. Subtyping of L. monocytogenes isolates using pulsed -field gel-electrophoresis revealed seven pulsotypes, of which two occurred in multiple samples. Targeted inoculum levels of 1-2 CFU/ml yielded L. monocytogenes counts 100 CFU/ml within seven days of storage in 22% of the raw milk packages stored at 6 degrees C, and in all of the raw milk packages stored at 8 degrees C. The frequent occurrence of L. monocytogenes in raw milk and the ability of a low-level L. monocytogenes contamination to grow at refrigeration temperatures highlight the importance of consumer education regarding the appropriate raw milk storage and handling.Peer reviewe

Epidemiology and growth potential of Listeria monocytogenes and Yersinia pseudotuberculosis in raw milk production

Consumer interest in drinking unpasteurized and unprocessed ‘raw milk’ has grown over the past decades. To understand risks associated with packaged raw milk, the epidemiology of L. monocytogenes and Y. pseudotuberculosis on dairy farms and the growth of these pathogens in raw milk was studied. The epidemiology of L. monocytogenes was investigated on three Finnish dairy farms. In 2013–2016, a total of 1,702 samples were collected from the farms from the barn environment, feed, water, feces and the milking equipment. In addition, 186 bulk tank milk samples and 224 milk filter samples were analyzed. Production hygiene was evaluated at the beginning and end of the study. L. monocytogenes was isolated and speciated using standard methods and subtyped using pulsed-field gel electrophoresis (PFGE). A subset 250 isolates were analyzed using whole genome sequencing. On all farms, L. monocytogenes occurred ubiquitously in the barn environment, particularly on the floors, water troughs, feeding surfaces and bedding. The occurrence of L. monocytogenes correlated with the level of hygiene on the farm. The occurrence of L. monocytogenes on udders or the milking equipment were identified as the main risk factors driving the occurrence of the pathogen in milk. Both sporadically occurring and recurring (‘persistent’) L. monocytogenes subtypes were isolated from the farms. The persistent subtypes accounted for most of the contamination load in the barn environment and in bulk tank milk. The epidemiology of Y. pseudotuberculosis was investigated on the outbreak-associated dairy farm during April to November 2014. A total 234 samples were obtained from milk, milk filters, feces, the barn environment, milking equipment and the raw milk packaging facility. Y. pseudotuberculosis were isolated and speciated from the samples using standard methods, subtyped using PFGE and a subset of 14 isolates were analyzed using whole genome sequencing. The outbreak-associated subtype of Y. pseudotuberculosis was detected in nearly all bulk tank milk and milk filter samples throughout the study, but it was absent in samples of feces and the farm environment. Deficiencies in feed hygiene and pest control were identified on farm visits, suggesting that Y. pseudotuberculosis may have been transmitted from wild animals accessing the feed stores and disseminated on the farm by the resident rodent population. The growth of L. monocytogenes and Y. pseudotuberculosis was investigated in raw milk packaged in bottles and bag-in-boxes stored at 6 °C. The growth studies indicated that both L. monocytogenes and Y. pseudotuberculosis grew in refrigerated raw milk, but the risk associated with the growth of these pathogens was not equal. During the 5-day shelf-life of the raw milk package, L. monocytogenes inoculated at a targeted level of 2 CFU/ml did not exceed the 100 CFU/g safety criterion. In contrast, Y. pseudotuberculosis inoculated at a targeted level of 2 CFU/ml grew very rapidly to infective levels in packaged raw milk. As the threat of foodborne pathogens can never be eliminated entirely from raw milk and heat treatment remains the best way to ensure milk safety.Raakamaito on maitoa, jota ei ole kuumennettu eikä muutoin käsitelty. Raakamaidon vähittäismyyntiin liittyvien riskien tunnistamiseksi on tärkeää selvittää, miten nopeasti jääkaappilämpötiloissa kasvavat taudinaiheuttajat, kuten Listeria monocytogenes ja Y. pseudotuberculosis lisääntyvät raakamaidossa. Lisäksi on tärkeä tunnistaa näiden taudinaiheuttajien tartuntareitit ja tartuntoja edistävät tekijät maidontuotantoympäristössä. L. monocytogenesin epidemiologiaa tutkittiin kolmella suomalaisella maitotilalla. Vuosina 2013–2016 tiloilta kerättiin yhteensä 2112 näytettä tankkimaidosta, lypsylaitteiston suodattimistia, navettaympäristöstä, rehusta, vedestä, ulosteista ja lypsylaitteistosta. Listeriaa esiintyi yleisesti rehuissa, lattioissa, juoma-astioissa, ruokintapinnoilla ja kuivikkeissa. L. monocytogenes -bakteerin esiintyminen vedinten ulkopinnalla tai lypsylaitteistossa olivat merkittäviä tankkimaidon saastumiselle altistavia tekijöitä. Tiloilla todettiin sekä satunnaisesti esiintyviä että toistuvasti eristettyjä (”pysyviä”) L. monocytogenes -kantoja. Pysyvät ja navettaympäristössä laajalle levinneet kannat muodostivat valtaosan tilan L. monocytogenes -kontaminaatiosta. Lähes kaikki pysyvät kannat eristettiin myös rehuista, osoittaen, että saastuneet rehut ylläpitävät listeriakontaminaatiota maitotiloilla. Y. pseudotuberculosis -bakteerin epidemiologiaa tutkittiin taudinpurkaukseen yhdistetyllä maitotilalla huhti-marraskuussa 2014. Tilalta kerättiin yhteensä 234 näytettä maidosta, suodattimista, ulosteesta, navettaympäristöstä, lypsylaitteistosta ja raakamaidon pakkauslaitoksesta. Taudinpurkauksen aiheuttanut Y. pseudotuberculosis -kanta eristettiin lähes kaikista tankkimaito- ja suodatinnäytteistä koko seurantajakson ajan, mutta sitä ei todettu ulosteissa tai navettaympäristössä. Tartunnan lähteenä epäiltiin subkliinista utaretulehdusta tai biofilmiä lypsylaitteistossa. Tilakäynneillä havaittiin puutteita rehuhygieniassa ja tuholaistorjunnassa. Y. pseudotuberculosis oli saattanut levitä tilalle rehuvarastoihin päässeistä haittaeläimistä ja levitä tilan jyrsijäpopulaatiossa. L. monocytogenes- ja Y. pseudotuberculosis -kantojen kasvua tutkittiin pulloihin ja hanapakkauksiin pakatussa raakamaidossa 6 °C:ssa. Kasvukokeet osoittivat, että sekä L. monocytogenes että Y. pseudotuberculosis kasvavat raakamaidossa jääkaappilämpötiloissa, mutta eri kasvunopeuksilla. L. monocytogeneksen kasvu raakamaidossa ei ylittänyt lakisääteistä raja-arvoa (100 pmy/g) raakamaitopakkauksen viiden vuorokauden säilyvyysajan puitteissa, kun maidon listeriamäärä oli kokeen alussa luonnollista saastuntaa vastaava (2 pmy/ml). Sen sijaan Y. pseudotuberculosis kasvoi alle viidessä vuorokaudessa tasolle, jossa 1 dl maitoa sisälsi tartuntaan riittävän annoksen, kun lähtötaso kokeen alussa oli luonnollista saastuntaa vastaava (2 pmy/ml). Pakkaustyyppi (pullo tai hanapakkas) ei ollut vaikuttanut merkittävästi taudinaiheuttajien kasvuun raakamaidossa. Tulokset osoittavat, että pakattuun raakamaitoon liittyy vaikeasti ehkäistäviä taudinaiheuttajariskejä. Koska taudinaiheuttajien uhkaa ei koskaan saada täysin poistettua, on raakamaidon pastörointi paras tapa turvata maidon elintarviketurvallisuus

Intergroup relations affect depressive symptoms of Indigenous people: Longitudinal evidence

One thousand eight hundred thirty‐five individuals who self‐identified as Indigenous (with Mapuche being the largest group) participated in a two‐wave longitudinal survey conducted in Chile with an 18 months lag. This was an approximately nationally representative sample of residents from culturally diverse communities. The aim of the study was to identify protective and adverse factors that are related to the development of depressive symptoms in Indigenous people. It was hypothesized that perceived social support would be negatively related to the development of depressive symptoms and that perceived discrimination would be positively associated with depressive symptoms, so that being on the receiving end of discrimination would make the manifestation of depressive symptoms more likely. Social support and perceived discrimination were themselves predicted to be affected by acculturation preferences and skin pigmentation. It was hypothesized that a positive acculturation orientation towards both the Indigenous group and members of non‐Indigenous majority society would be associated with more perceived social support. Hence, preference for culture maintenance and preference for cross‐group contact were expected to be positively related to social support. Further, it was hypothesized that darker skin pigmentation would be associated with more experiences of discrimination. Taken together, two processes were expected to affect depressive symptomatology: a protective effect of acculturation preferences mediated by social support and a deleterious effect of pigmentation mediated by experiences of discrimination. Results confirmed the predictions cross‐sectionally but longitudinal effects were only found for the deleterious effect of pigmentation; the protective effect of acculturation preferences was notably weaker over time. These findings have both theoretical and applied implications

Creating Lakes from Open Pit Mines: Processes and Considerations, Emphasis on Northern Environments

Creating Lakes from Open Pit Mines: Processes and Considerations, Emphasis on Northern Environments. This document summarizes the literature of mining pit lakes (through 2007), with a particular focus on issues that are likely to be of special relevance to the creation and management of pit lakes in northern climates. Pit lakes are simply waterbodies formed by filling the open pit left upon the completion of mining operations with water. Like natural lakes, mining pit lakes display a huge diversity in each of these subject areas. However, pit lakes are young and therefore are typically in a non-equilibrium state with respect to their rate of filling, water quality, and biology. Separate sections deal with different aspects of pit lakes, including their morphometry, geology, hydrogeology, geochemistry, and biology. Depending on the type and location of the mine, there may be opportunities to enhance the recreational or ecological benefits of a given pit lake, for example, by re-landscaping and re-vegetating the shoreline, by adding engineered habitat for aquatic life, and maintaining water quality. The creation of a pit lake may be a regulatory requirement to mitigate environmental impacts from mining operations, and/or be included as part of a closure and reclamation plan. Based on published case studies of pit lakes, large-scale bio-engineering projects have had mixed success. A common consensus is that manipulation of pit lake chemistry is difficult, expensive, and takes many years to achieve remediation goals. For this reason, it is prudent to take steps throughout mine operation to reduce the likelihood of future water quality problems upon closure. Also, it makes sense to engineer the lake in such a way that it will achieve its maximal end-use potential, whether it be permanent and safe storage of mine waste, habitat for aquatic life, recreation, or water supply

Processos de criação do livro para a infância: imagem, palavra e construção poética

Editorial n. 37. Dossiê: Processos de criação do livro para a infância: imagem, palavra e construção poétic

Genomic Epidemiology and Phenotyping Reveal on-Farm Persistence and Cold Adaptation of Raw Milk Outbreak-Associated Yersinia pseudotuberculosis

Free PMC article: https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/31156582/Packaged raw milk contaminated with Yersinia pseudotuberculosis mediated a large yersiniosis outbreak in southern Finland in 2014. The outbreak was traced back to a single dairy farm in southern Finland. Here we explore risk factors leading to the outbreak through epidemiologic investigation of the outbreak farm and through genomic and phenotypic characterization of the farm's outbreak and non-outbreak associated Y. pseudotuberculosis strains. We show that the outbreak strain persisted on the farm throughout the 7-month study, whereas the non-outbreak strains occurred sporadically. Phylogenomic analysis illustrated that the outbreak strain was related to previously published genomes of wild animal isolates from Finland, implying that wild animals were a potential source of the outbreak strain to the farm. We observed allelic differences between the farm's outbreak and non-outbreak strains in several genes associated with virulence, stress response and biofilm formation, and found that the outbreak strain formed biofilm in vitro and maintained better growth fitness during cold stress than the non-outbreak strains. Finally, we demonstrate the rapid growth of the outbreak strain in packaged raw milk during refrigerated storage. This study provides insight of the risk factors leading to the Y. pseudotuberculosis outbreak, highlights the importance of pest control to avoid the spread of pathogens from wild to domestic animals, and demonstrates that the cold chain is insufficient as the sole risk management strategy to control Y. pseudotuberculosis risk associated with raw drinking milk.This research was supported by the Finnish Ministry of Agriculture and Forestry grant Dnro: 1395/311/214, the Walter Ehrström Foundation, and the University of Helsinki Doctoral Program in Food Chain and Health. The sequencing of the strains and the salary of AJ and JI were supported by the INNUENDO project (https://sites.google.com/site/theinnuendoproject/) which received funding from the European Food Safety Authority, grant agreement GP/EFSA/AFSCO/2015/01/CT2 (“New approaches in identifying and characterizing microbial and chemical hazards”).info:eu-repo/semantics/publishedVersio

Expression of Retinoid Acid Receptor-Responsive Genes in Rodent Models of Placental Pathology

In humans, retinoic acid receptor responders (RARRES) have been shown to be altered in third trimester placentas complicated by the pathologies preeclampsia (PE) and PE with intrauterine growth restriction (IUGR). Currently, little is known about the role of placental Rarres in rodents. Therefore, we examined the localization and expression of Rarres1 and 2 in placentas obtained from a Wistar rat model of isocaloric maternal protein restriction (E18.5, IUGR-like features) and from an eNOS-knockout mouse model (E15 and E18.5, PE-like features). In both rodent models, Rarres1 and 2 were mainly localized in the placental spongiotrophoblast and giant cells. Their placental expression, as well as the expression of the Rarres2 receptor chemokine-like receptor 1 (CmklR1), was largely unaltered at the examined gestational ages in both animal models. Our results have shown that RARRES1 and 2 may have different expression and roles in human and rodent placentas, thereby underlining immanent limitations of comparative interspecies placentology. Further functional studies are required to elucidate the potential involvement of these proteins in early placentogenesis

Bacteriocin production by Escherichia coli during biofilm development

Escherichia coli is a highly versatile bacterium ranging from commensal to intestinal pathogen, and is an important foodborne pathogen. E. coli species are able to prosper in multispecies biofilms and secrete bacteriocins that are only toxic to species/strains closely related to the producer strain. In this study, 20 distinct E. coli strains were characterized for several properties that confer competitive advantages against closer microorganisms by assessing the biofilm-forming capacity, the production of antimicrobial molecules, and the production of siderophores. Furthermore, primer sets for E. coli bacteriocins–colicins were designed and genes were amplified, allowing us to observe that colicins were widely distributed among the pathogenic E. coli strains. Their production in the planktonic phase or single-species biofilms was uncommon. Only two E. coli strains out of nine biofilm-forming were able to inhibit the growth of other E. coli strains. There is evidence of larger amounts of colicin being produced in the late stages of E. coli biofilm growth. The decrease in bacterial biomass after 12 h of incubation indicates active type I colicin production, whose release normally requires E. coli cell lysis. Almost all E. coli strains were siderophore-producing, which may be related to the resistance to colicin as these two molecules may use the same transporter system. Moreover, E. coli CECT 504 was able to coexist with Salmonella enterica in dual-species biofilms, but Shigella dysenteriae was selectively excluded, correlating with high expression levels of colicin (E, B, and M) genes observed by real-time PCR.info:eu-repo/semantics/publishedVersio

Influence of papain in biofilm formed by methicillin-resistant Staphylococcus epidermidis and methicillin-resistant Staphylococcus haemolyticus isolates

Methicillin-resistant Staphylococcus epidermidis (MRSE) and methicillin-resistant Staphylococcus haemolyticus (MRSHa) are important coagulase-negative staphylococci. They are often isolated from bacteremia in humans mainly due to their ability to form biofilm on the surfaces of medical devices. Papain is a complex mixture of proteolytic enzymes and peroxidases extracted from the latex of Carica papaya and it is recognized by accelerating the healing process of wounds. This study aimed to evaluate the ability of the MRSE and MRSHa isolates to produce biofilms. Besides this, the ability of papain to inhibit the formation of biofilms or to disrupt the ones already formed by those bacteria was analyzed. Thirty MRSHa and 30 MRSE were isolated from bacteremia and used in this study. It was observed that papain has ability to reduce biofilms formed by MRSE (p < 0.06) and by MRSHa (p = 0.0005). In addition, papain was able to disrupt mature biofilms made by MRSE (p = 0.014). No antibacterial activity of papain was observed for any isolates of MRSE and MRSHa tested. Papain has been demonstrated as a potential product for reducing biofilm.Staphylococcus epidermidis resistente à meticilina (MRSE) e Staphylococcus haemolyticus resistente à meticilina (MRSHa) são importantes estafilococos coagulase negativa. São frequentemente isolados em bacteremia humana, principalmente devido à capacidade de formar biofilmes nas superfícies de dispositivos médicos introduzidos no organismo. A papaína é mistura complexa de enzimas proteolíticas e peroxidases extraídas do látex de Carica papaya, reconhecida por acelerar os processos de cura de feridas. Este estudo teve como objetivo avaliar a capacidade dos MRSE e MRSHa em produzir biofilmes e analisar a capacidade da papaína em inibir a formação de biofilme ou desintegrar biofilmes já formados por essas bactérias. Observou-se que a papaína tem capacidade de reduzir a formação de biofilme por MRSE (p < 0,06) e MRSHa (p = 0,0005). Além disso, a papaína foi capaz de desintegrar biofilme maduro formado por MRSE (p = 0,014). Nenhuma atividade antibacteriana da papaína foi observada para qualquer das duas espécies de bactérias testadas. A papaína mostrou-se produto potencial para reduzir biofilme

Inclusão e professores: representações discursivas

O tema Inclusão tem-se destacado como uma forma revolucionária da educação, entende-se que analisar os discursos veiculados sobre este tema, contribui para elucidar certos aspectos que não são ditos (as entrelinhas) explicitamente, mas que direcionam a maneira de pensar e de agir da pessoa que os lê, já que quem escreveu tal artigo para a Revista tem sua história, sua ideologia, sua opinião formada sobre a temática e que influencia a maneira de pensar de quem lê tal reportagem. Partindo dos pressupostos teóricos da Análise do Discurso (AD) e da educação inclusiva, pretende-se, a partir da análise do artigo “A escola que é de todas as crianças” do site da Revista Nova Escola, edição n.º 182, do mês de maio de 2005, de autoria de Meire Cavalcante, cuja temática é a educação inclusiva, entender os discursos veiculados sobre a temática, que ideias difundem, que representações o artigo da Revista sob análise veicula sobre inclusão. Portanto, na análise, conforme apregoado na manchete em questão, o termo inclusão, mediante a ação do professor, é capaz de transformar os modos de pensar e agir das pessoas com deficiência, esquecendo que, na realidade, as escolas estão deficientes em vários sentidos: estrutura física, pedagógicas e tecnológicas, falta investimento na formação de todos os envolvidos no processo ensino/aprendizagem, sendo que tudo isso interfere nos resultados do processo de inclusão, ou seja, para uma educação de maior qualidade. Não é somente a ação isolada do professor que trará resultados profícuos nesse processo.Palavras-chave: Análise do discurso. Inclusão. Professores