Acid resistance of Salmonella Typhimurium ATCC 14028 after desiccation stress during peanut storage / Avaliação da resistência ácida de Salmonella Typhimurium ATCC 14028 após o estresse dessecativo durante o armazenamento de amendoim

Salmonella is a relevant pathogen, which causes foodborne outbreaks associated with both high and low moisture foods (LMF). This study evaluated the effect of previous desiccation stress on the acid resistance of S. Typhimurium ATCC 14028 using blanched peanut kernels as an LMF model. Salmonella was recovered from the peanut samples throughout 180 days of blanched peanut kernels storage at 28 ºC. During this period two death rates were verified, 0.04 log cfu/g/day in the first 30 days and 0.007 log cfu/g/day between 30 and180 days.Regarding acid resistance, there was no difference (P > 0.05) in the Salmonella growth/death kinetics between the undesiccated sample (TSB)and the cells recovered from peanut samples over 180 days of storage after 4 h at pHs 3.0, 3.5, 4.5 and 7.2. The average growth rate observed for pH 7.2 was 0.44 log cfu/ml/h. At pH 4.5, the Salmonella counts did not change significantly over 4 h. In contrast, Salmonella populations declined by 0.14 to 0.29 log cfu/ml/h at pH 3.5. At pH 3.0 declines were estimated to be 0.65 log cfu/ml/h for the undesiccated sample and 2.07 log cfu/ml/h for Salmonella recovered from peanuts stored for 120 days. Therefore, our data indicated that desiccation stress caused during the peanut storagedid not influence the Salmonella acid resistance.

Em alimentos de baixa umidade (LMF), o primeiro desafio encontrado por patógenos como a Salmonella é o estresse de dessecação. Neste estudo, o efeito prévio do estresse de dessecação sobre a resistência ácida de S. Typhimurium ATCC 14028 foi avaliado utilizando amendoim blancheado como um modelo de LMF. Salmonella foi recuperada das amostras de amendoim após 180 dias de estocagem a 28 ºC. Durante este período foram verificadas duas taxas de mortalidade, 0,04 log ufc/g/dia nos primeiros 30 dias e 0,007 log ufc/g/dia entre 30 e 180 dias. Com relação à resistência ácida, não houve diferença (P > 0,05) na cinética de crescimento/morte de Salmonella entre a amostra sem estresse dessecativo (TSB) e as amostras de amendoim após 4 h em pHs 3,0, 3,5, 4,5 e 7,2. A taxa média de crescimento observada para o pH 7,2 foi de 0,44 log cfu/ml/h. No pH 4,5, a contagem de Salmonella não mudou significativamente durante 4 h. Em contraste, a população de Salmonella diminuiu de 0,14 a 0,29 log cfu/ml/h no pH 3,5. No pH 3,0, a queda foi estimada em 0,65 log cfu/ml/h para a amostra sem estresse dessecativo e 2,07 log cfu/ml/h para a Salmonella recuperada das amostras de amendoim estocadas por 120 dias. Portanto, nossos dados indicaram que o estresse dessecativo causado durante a estocagem do amendoim não influenciou a resistência ácida de Salmonella.

Use of organic acids to reduce Salmonella Typhimurium excretion in swine / Uso de ácidos orgânicos para reduzir a excreção de Salmonella Typhimurium em suínos

The use of antimicrobials as growth promoters and disease prevention is being constantly reduced in several animal production systems, including in the swine industry. Therefore, this study aimed to evaluate the effectiveness of using acidifiers to control Salmonella Typhimurium in 65-day-old pigs by detecting the pathogen in organs at euthanasia. For this, 24 piglets were divided into two experimental groups consisting of 12 piglets each. An untreated control group (G1) and a treatment group (G2) received a liquid organic acidifier in the drinking water for 10 days (D-5 to D5). Five days after the start of treatment (D0), all piglets were challenged with 106 CFU of Salmonella Typhimurium and assessed for 12 days (D12). Every three days (D3, D6, D9, and D12), three animals from each experimental group were euthanized and then submitted for necropsy. Samples from the intestines (ileum, cecum, mesenteric lymph nodes, and ileocolic lymph nodes), liver, spleen, and lungs were collected to isolate Salmonella. The results show that, numerically, Salmonella isolation in the organs of G2 was lower than in G1 and that the number of positive cecum samples in G1 (66.7%; 8/12) was statistically different from the number of positive models in G2 (16.7%; 2/12), with a reduction of 28.6% of the total cecum positive samples in the treated group compared to the control. Therefore, it was observed that the liquid organic acidifier product could reduce the colonization of organs by Salmonella Typhimurium. (AU)

Use of organic acids to reduce Salmonella Typhimurium excretion in swine / Uso de ácidos orgânicos para reduzir a excreção de Salmonella Typhimurium em suínos

The use of antimicrobials as growth promoters and disease prevention is being constantly reduced in several animal production systems, including in the swine industry. Therefore, this study aimed to evaluate the effectiveness of using acidifiers to control Salmonella Typhimurium in 65-day-old pigs by detecting the pathogen in organs at euthanasia. For this, 24 piglets were divided into two experimental groups consisting of 12 piglets each. An untreated control group (G1) and a treatment group (G2) received a liquid organic acidifier in the drinking water for 10 days (D-5 to D5). Five days after the start of treatment (D0), all piglets were challenged with 106 CFU of Salmonella Typhimurium and assessed for 12 days (D12). Every three days (D3, D6, D9, and D12), three animals from each experimental group were euthanized and then submitted for necropsy. Samples from the intestines (ileum, cecum, mesenteric lymph nodes, and ileocolic lymph nodes), liver, spleen, and lungs were collected to isolate Salmonella. The results show that, numerically, Salmonellaisolation in the organs of G2 was lower than in G1 and that the number of positive cecum samples in G1 (66.7%; 8/12) was statistically different from the number of positive models in G2 (16.7%; 2/12), with a reduction of 28.6% of the total cecum positive samples in the treated group compared to the control. Therefore, it was observed that the liquid organic acidifier product could reduce the colonization of organs by Salmonella Typhimurium.(AU)

O uso de antimicrobianos como promotores de crescimento e prevenção de doenças vem sendo constantemente reduzido em diversos sistemas de produção animal, inclusive na suinocultura. Portanto, o objetivo do presente estudo foi avaliar a eficácia do uso de acidificantes no controle de Salmonella Typhimurium em suínos de 65 dias de idade, detectando o patógeno em órgãos após a eutanásia. Para isso, 24 leitões foram divididos em dois grupos experimentais constituídos por 12 leitões cada. Um grupo controle não tratado (G1) e um grupo de tratamento (G2) que recebeu um acidificante orgânico líquido na água de beber por 10 dias (D-5 a D5). Cinco dias após o início do tratamento (D0), todos os animais foram inoculados oralmente com 106 UFC de Salmonella Typhimurium e avaliados por 12 dias (D12). A cada três dias (D3, D6, D9 e D12), três leitões de cada grupo experimental foram eutanasiados e posteriormente submetidos à necropsia. Amostras de intestino (íleo, ceco, linfonodos mesentéricos e linfonodos ileocólicos), fígado, baço e pulmões foram coletadas para o isolamento de Salmonella. Os resultados mostram que, numericamente, o isolamento de Salmonella nos órgãos do G2 foi inferior ao G1, e que o número de amostras positivas de ceco no G1 (66,7%; 8/12) foi estatisticamente diferente do número de amostras positivas no G2 (16,7%; 2/12), com redução de 28,6% do total de amostras positivas de ceco no grupo tratado em relação ao controle. Portanto, observou-se que o ácido orgânico líquido foi capaz de reduzir a colonização de órgãos por Salmonella Typhimurium.(AU)

Acid resistance of Salmonella Typhimurium ATCC 14028 after desiccation stress during peanut storage / Avaliação da resistência ácida de Salmonella Typhimurium ATCC 14028 após o estresse dessecativo durante o armazenamento de amendoim

ABSTRACT: Salmonella is a relevant pathogen, which causes foodborne outbreaks associated with both high and low moisture foods (LMF). This study evaluated the effect of previous desiccation stress on the acid resistance of S. Typhimurium ATCC 14028 using blanched peanut kernels as an LMF model. Salmonella was recovered from the peanut samples throughout 180 days of blanched peanut kernels storage at 28 ºC. During this period two death rates were verified, 0.04 log cfu/g/day in the first 30 days and 0.007 log cfu/g/day between 30 and180 days.Regarding acid resistance, there was no difference (P > 0.05) in the Salmonella growth/death kinetics between the undesiccated sample (TSB)and the cells recovered from peanut samples over 180 days of storage after 4 h at pHs 3.0, 3.5, 4.5 and 7.2. The average growth rate observed for pH 7.2 was 0.44 log cfu/ml/h. At pH 4.5, the Salmonella counts did not change significantly over 4 h. In contrast, Salmonella populations declined by 0.14 to 0.29 log cfu/ml/h at pH 3.5. At pH 3.0 declines were estimated to be 0.65 log cfu/ml/h for the undesiccated sample and 2.07 log cfu/ml/h for Salmonella recovered from peanuts stored for 120 days. Therefore, our data indicated that desiccation stress caused during the peanut storagedid not influence the Salmonella acid resistance.

RESUMO: Em alimentos de baixa umidade (LMF), o primeiro desafio encontrado por patógenos como a Salmonella é o estresse de dessecação. Neste estudo, o efeito prévio do estresse de dessecação sobre a resistência ácida de S. Typhimurium ATCC 14028 foi avaliado utilizando amendoim blancheado como um modelo de LMF. Salmonella foi recuperada das amostras de amendoim após 180 dias de estocagem a 28 ºC. Durante este período foram verificadas duas taxas de mortalidade, 0,04 log ufc/g/dia nos primeiros 30 dias e 0,007 log ufc/g/dia entre 30 e 180 dias. Com relação à resistência ácida, não houve diferença (P > 0,05) na cinética de crescimento/morte de Salmonella entre a amostra sem estresse dessecativo (TSB) e as amostras de amendoim após 4 h em pHs 3,0, 3,5, 4,5 e 7,2. A taxa média de crescimento observada para o pH 7,2 foi de 0,44 log cfu/ml/h. No pH 4,5, a contagem de Salmonella não mudou significativamente durante 4 h. Em contraste, a população de Salmonella diminuiu de 0,14 a 0,29 log cfu/ml/h no pH 3,5. No pH 3,0, a queda foi estimada em 0,65 log cfu/ml/h para a amostra sem estresse dessecativo e 2,07 log cfu/ml/h para a Salmonella recuperada das amostras de amendoim estocadas por 120 dias. Portanto, nossos dados indicaram que o estresse dessecativo causado durante a estocagem do amendoim não influenciou a resistência ácida de Salmonella.

Portrayal of Punica granatum L. peel extract through High Performance Liquid Chromatography and antimicrobial activity evaluation

Abstract Increasing trend in antimicrobial resistance and failure of chemically synthesized antibiotics lead to discover alternative methods for the treatment of bacterial infections. Various medicinal plants are in use traditionally and their active compounds can be further applied for treatment of bacterial diseases. This study was designed to determine the antibacterial activity of Punica granatum (P. granatum L.) (pomegranate) peel extract against Enterobacteriaceae [Escherichia coli (E. coli), Salmonella Typhimurium (S. Typhimurium) and Shigella Dysenteriae (S. Dysenteriae)] and gram-positive bacterium [Staphylococcus aureus (Staph aureus)]. Methanolic extract of P. granatum L. peel was prepared by Soxhlet apparatus method. Total flavonoid and phenolic contents from the extract were determined by High Performance Liquid Chromatography (HPLC). The antibacterial activity of P. granatum L. peel extract was evaluated through agar well diffusion method. HPLC showed the range of phenolics (gallic acid, caffeic acid, benzoic acid, cinnamic acid) and flavonoid compounds. The chemical structures of flavonoid and phenolics found in the methanolic extract of P. granatum L. peel have been reported for the first time. The methanolic peel extract (50 ul) of yellow P. granatum L. showed 26, 10, 10 and 9mm zones of inhibition (ZOI) against S. aureus, S. Typhimurium, S. Dysenteriae and E. coli, respectively. The methanolic extract of red P. granatum L. (100 ul) showed 27, 8, 12 and 15 mm ZOI against Staph. aureus, S. Typhimurium, S. Dysenteriae and E. coli, respectively. Highest ZOI was observed against Staph. aureus. Many of the bacteria studied in the present work may cause serious gastrointestinal infections, which can lead to hemorrhagic diarrhea in children. These infections can be life-threatening to young children and the elderly. There is an incentive to find alternative control measures, such as plant and herbal extracts, especially in lesser-developed countries where traditional antibiotics may not be readily available.

Resumo A tendência crescente na resistência antimicrobiana e na falha dos antibióticos sintetizados quimicamente leva à descoberta de métodos alternativos para o tratamento de infecções bacterianas. Várias plantas medicinais estão em uso tradicionalmente e seus compostos ativos podem ser posteriormente aplicados para o tratamento de doenças bacterianas. Este estudo foi desenhado para determinar a atividade antibacteriana do extrato de casca de Punica granatum (P. granatum L.) (romã) contra Enterobacteriaceae [Escherichia coli (E. coli), Salmonella Typhimurium (S. Typhimurium) e Shigella Dysenteriae (S. Dysenteriae) ] e bactéria gram-positiva [Staphylococcus aureus (Staph aureus)]. O extrato metanólico da casca de P. granatum L. foi preparado pelo método do aparelho de Soxhlet. O conteúdo total de flavonoides e fenólicos do extrato foi determinado por cromatografia líquida de alta eficiência (HPLC). A atividade antibacteriana do extrato da casca de P. granatum L. foi avaliada através do método de difusão em ágar. HPLC mostrou a gama de compostos fenólicos (ácido gálico, ácido cafeico, ácido benzoico, ácido cinâmico) e flavonoides. As estruturas químicas de flavonoides e fenólicos encontradas no extrato metanólico da casca de P. granatum L. foram relatadas pela primeira vez. O extrato metanólico da casca (50 ul) de P. granatum L. amarelo apresentou zonas de inibição (ZOI) de 26, 10, 10 e 9mm contra S. aureus, S. Typhimurium, S. Dysenteriae e E. coli, respectivamente. O extrato metanólico de P. granatum L. vermelho (100 ul) apresentou 27, 8, 12 e 15 mm IOI contra Staph. aureus, S. Typhimurium, S. Dysenteriae e E. coli, respectivamente. O ZOI mais alto foi observado contra Staph. aureus. Muitas das bactérias estudadas no presente trabalho podem causar infecções gastrointestinais graves, que podem levar à diarreia hemorrágica em crianças. Essas infecções podem ser fatais para crianças pequenas e idosos. Há um incentivo para encontrar medidas de controle alternativas, como extratos de plantas e ervas, especialmente em países menos desenvolvidos, onde os antibióticos tradicionais podem não estar prontamente disponíveis.

Identification and characterization of pathogenic and multidrug-resistant bacteria in feral pigeons surrounding a veterinary hospital in Minas Gerais, Brazil / Identificação de bactérias patogênicas e multirresistentes a antimicrobianos em pombos urbanos no entorno de um Hospital Veterinário em Belo Horizonte, Minas Gerais, Brasil

Pigeons are known for their capacity to harbor and spread several zoonotic agents. Studies have suggested that pigeons are also relevant disseminators of multidrug-resistant strains. In this study, pigeons surrounding a veterinary hospital were sampled and tested for the presence of pathogenic Escherichia coli, Salmonella spp., Staphylococcus spp., and Clostridioides (Clostridium) difficile. E. coli isolates from 19 (40.4%) pigeons tested positive for the E. coli heat-stable enterotoxin 1 (EAST1)-encoding gene. The intimin-encoding gene (eae) of enteropathogenicE. coli (EPEC) was found in one isolate (2.1%). Salmonella spp. were found in nine (19.1%) pigeons, all from the first capture event (P < 000.1). S. Typhimurium and S. Heidelberg were isolated from six and three pigeons, respectively. Enterobacterial repetitive intergenic consensus (ERIC-PCR) of the Salmonella spp. isolates suggested that eight of the nine strains had a high genetic similarity, supporting the hypothesis of an outbreak of salmonellosis in these pigeons. Twenty (42.5%) staphylococcal isolates were recovered from 18 (38.3%) pigeons. Eight different species were detected, with S. xylosus being the most frequent. Two (4.3%) C. difficile strains were isolated. Three isolates, one each of S. Typhimurium, S. aureus, and C. difficile, were classified as multidrug-resistant strains. The present research suggested that pigeons residing in urban areas can act as reservoirs and disseminators of pathogenic bacteria, including nosocomial pathogens, such as diarrheagenicE. coli and multidrug-resistant Staphylococcus spp., C. difficile, and Salmonella spp.

Pombos urbanos são conhecidos pela sua capacidade de carrear e disseminar diversos agentes zoonóticos. Estudos tem sugerido que pombos são também relevantes na disseminação de estirpes resistentes a múltiplas drogas. No presente estudo, pombos no ambiente de um hospital veterinário foram amostrados em três diferentes períodos e testados para a presença de Escherichia coli patogênica, Salmonella spp., Staphylococcus spp. e Clostridioides (Clostridium) difficile. Isolados de E. coli de 19 pombos (40.4%) foram positivos para o gene codificador da toxina EAST1. O gene codificador de intimina (eae) do patotipo E. coli enteropatogênica foi encontrada em um isolado (2.1%). Salmonella spp. foi encontrada em nove pombos (19.1%), sendo todos isolados do primeiro período de captura (P < 000.1). S. Typhimurium foi isolado de seis animais e S. Heidelberg de três. A tipagem molecular de isolados de Salmonella spp. por ERIC-PCR demonstrou que oito estirpes possuíam alta similaridade genética entre si, sugerindo a ocorrência de um surto de salmonelose nos animais carreadores. Vinte Staphylococcus (42.5%) foram isolados de 18 animais (38.3%). Oito diferentes espécies foram detectadas, sendo S. xylosus a mais frequente. Duas estirpes de C. difficile não-toxigênica (4.3%) foram isoladas. Uma estirpe de S. Typhimurium, uma de S. aureus e um isolado de C. difficile foram classificados como resistentes a múltiplas drogas antimicrobianas. O presente estudo sugere que pombos capturados no ambiente do hospital veterinário podem atuar como reservatórios e disseminadores de bactérias patogênicas e envolvidas em infecção hospitalar, incluindo E. coli diarreiogênica e Staphylococcus sp., C. difficile e Salmonella spp multirresistente.

Portrayal of Punica granatum L. peel extract through High Performance Liquid Chromatography and antimicrobial activity evaluation / Retrato do extrato de casca de Punica granatum L. por meio de cromatografia líquida de alto desempenho e avaliação da atividade antimicrobiana

Abstract Increasing trend in antimicrobial resistance and failure of chemically synthesized antibiotics lead to discover alternative methods for the treatment of bacterial infections. Various medicinal plants are in use traditionally and their active compounds can be further applied for treatment of bacterial diseases. This study was designed to determine the antibacterial activity of Punica granatum (P. granatum L.) (pomegranate) peel extract against Enterobacteriaceae [Escherichia coli (E. coli), Salmonella Typhimurium (S. Typhimurium) and Shigella Dysenteriae (S. Dysenteriae)] and gram-positive bacterium [Staphylococcus aureus (Staph aureus)]. Methanolic extract of P. granatum L. peel was prepared by Soxhlet apparatus method. Total flavonoid and phenolic contents from the extract were determined by High Performance Liquid Chromatography (HPLC). The antibacterial activity of P. granatum L. peel extract was evaluated through agar well diffusion method. HPLC showed the range of phenolics (gallic acid, caffeic acid, benzoic acid, cinnamic acid) and flavonoid compounds. The chemical structures of flavonoid and phenolics found in the methanolic extract of P. granatum L. peel have been reported for the first time. The methanolic peel extract (50 ul) of yellow P. granatum L. showed 26, 10, 10 and 9mm zones of inhibition (ZOI) against S. aureus, S. Typhimurium, S. Dysenteriae and E. coli, respectively. The methanolic extract of red P. granatum L. (100 ul) showed 27, 8, 12 and 15 mm ZOI against Staph. aureus, S. Typhimurium, S. Dysenteriae and E. coli, respectively. Highest ZOI was observed against Staph. aureus. Many of the bacteria studied in the present work may cause serious gastrointestinal infections, which can lead to hemorrhagic diarrhea in children. These infections can be life-threatening to young children and the elderly. There is an incentive to find alternative control measures, such as plant and herbal extracts, especially in lesser-developed countries where traditional antibiotics may not be readily available.

Resumo A tendência crescente na resistência antimicrobiana e na falha dos antibióticos sintetizados quimicamente leva à descoberta de métodos alternativos para o tratamento de infecções bacterianas. Várias plantas medicinais estão em uso tradicionalmente e seus compostos ativos podem ser posteriormente aplicados para o tratamento de doenças bacterianas. Este estudo foi desenhado para determinar a atividade antibacteriana do extrato de casca de Punica granatum (P. granatum L.) (romã) contra Enterobacteriaceae [Escherichia coli (E. coli), Salmonella Typhimurium (S. Typhimurium) e Shigella Dysenteriae (S. Dysenteriae) ] e bactéria gram-positiva [Staphylococcus aureus (Staph aureus)]. O extrato metanólico da casca de P. granatum L. foi preparado pelo método do aparelho de Soxhlet. O conteúdo total de flavonoides e fenólicos do extrato foi determinado por cromatografia líquida de alta eficiência (HPLC). A atividade antibacteriana do extrato da casca de P. granatum L. foi avaliada através do método de difusão em ágar. HPLC mostrou a gama de compostos fenólicos (ácido gálico, ácido cafeico, ácido benzoico, ácido cinâmico) e flavonoides. As estruturas químicas de flavonoides e fenólicos encontradas no extrato metanólico da casca de P. granatum L. foram relatadas pela primeira vez. O extrato metanólico da casca (50 ul) de P. granatum L. amarelo apresentou zonas de inibição (ZOI) de 26, 10, 10 e 9mm contra S. aureus, S. Typhimurium, S. Dysenteriae e E. coli, respectivamente. O extrato metanólico de P. granatum L. vermelho (100 ul) apresentou 27, 8, 12 e 15 mm IOI contra Staph. aureus, S. Typhimurium, S. Dysenteriae e E. coli, respectivamente. O ZOI mais alto foi observado contra Staph. aureus. Muitas das bactérias estudadas no presente trabalho podem causar infecções gastrointestinais graves, que podem levar à diarreia hemorrágica em crianças. Essas infecções podem ser fatais para crianças pequenas e idosos. Há um incentivo para encontrar medidas de controle alternativas, como extratos de plantas e ervas, especialmente em países menos desenvolvidos, onde os antibióticos tradicionais podem não estar prontamente disponíveis.

Portrayal of Punica granatum L peel extract through High Performance Liquid Chromatography and antimicrobial activity evaluation / Retrato do extrato de casca de Punica granatum L por meio de cromatografia líquida de alto desempenho e avaliação da atividade antimicrobiana

ncreasing trend in antimicrobial resistance and failure of chemically synthesized antibiotics lead to discover alternative methods for the treatment of bacterial infections. Various medicinal plants are in use traditionally and their active compounds can be further applied for treatment of bacterial diseases. This study was designed to determine the antibacterial activity of Punica granatum (P. granatum L.) (pomegranate) peel extract against Enterobacteriaceae [Escherichia coli (E. coli), Salmonella Typhimurium (S. Typhimurium) and Shigella Dysenteriae (S. Dysenteriae)] and gram-positive bacterium [Staphylococcus aureus (Staph aureus)]. Methanolic extract of P. granatum L. peel was prepared by Soxhlet apparatus method. Total flavonoid and phenolic contents from the extract were determined by High Performance Liquid Chromatography (HPLC). The antibacterial activity of P. granatum L. peel extract was evaluated through agar well diffusion method. HPLC showed the range of phenolics (gallic acid, caffeic acid, benzoic acid, cinnamic acid) and flavonoid compounds. The chemical structures of flavonoid and phenolics found in the methanolic extract of P. granatum L. peel have been reported for the first time. The methanolic peel extract (50 ul) of yellow P. granatum L. showed 26, 10, 10 and 9mm zones of inhibition (ZOI) against S. aureus, S. Typhimurium, S. Dysenteriae and E. coli, respectively. The methanolic extract of red P. granatum L. (100 ul) showed 27, 8, 12 and 15 mm ZOI against Staph. aureus, S. Typhimurium, S. Dysenteriae and E. coli, respectively. Highest ZOI was observed against Staph. aureus. Many of the bacteria studied in the present work may cause serious gastrointestinal infections, which can lead to hemorrhagic diarrhea in children. These [...].

A tendência crescente na resistência antimicrobiana e na falha dos antibióticos sintetizados quimicamente leva à descoberta de métodos alternativos para o tratamento de infecções bacterianas. Várias plantas medicinais estão em uso tradicionalmente e seus compostos ativos podem ser posteriormente aplicados para o tratamento de doenças bacterianas. Este estudo foi desenhado para determinar a atividade antibacteriana do extrato de casca de Punica granatum (P. granatum L.) (romã) contra Enterobacteriaceae [Escherichia coli (E. coli), Salmonella Typhimurium (S. Typhimurium) e Shigella Dysenteriae (S. Dysenteriae) ] e bactéria gram-positiva [Staphylococcus aureus (Staph aureus)]. O extrato metanólico da casca de P. granatum L. foi preparado pelo método do aparelho de Soxhlet. O conteúdo total de flavonoides e fenólicos do extrato foi determinado por cromatografia líquida de alta eficiência (HPLC). A atividade antibacteriana do extrato da casca de P. granatum L. foi avaliada através do método de difusão em ágar. HPLC mostrou a gama de compostos fenólicos (ácido gálico, ácido cafeico, ácido benzoico, ácido cinâmico) e flavonoides. As estruturas químicas de flavonoides e fenólicos encontradas no extrato metanólico da casca de P. granatum L. foram relatadas pela primeira vez. O extrato metanólico da casca (50 ul) de P. granatum L. amarelo apresentou zonas de inibição (ZOI) de 26, 10, 10 e 9mm contra S. aureus, S. Typhimurium, S. Dysenteriae e E. coli, respectivamente. O extrato metanólico de P. granatum L. vermelho (100 ul) apresentou 27, 8, 12 e 15 mm IOI contra Staph. aureus, S. Typhimurium, S. Dysenteriae e E. coli, respectivamente. O ZOI mais alto foi observado contra Staph. aureus. Muitas das bactérias estudadas no presente trabalho podem causar infecções gastrointestinais graves, que podem levar à diarreia [...].

Portrayal of Punica granatum L peel extract through High Performance Liquid Chromatography and antimicrobial activity evaluation / Retrato do extrato de casca de Punica granatum L por meio de cromatografia líquida de alto desempenho e avaliação da atividade antimicrobiana

ncreasing trend in antimicrobial resistance and failure of chemically synthesized antibiotics lead to discover alternative methods for the treatment of bacterial infections. Various medicinal plants are in use traditionally and their active compounds can be further applied for treatment of bacterial diseases. This study was designed to determine the antibacterial activity of Punica granatum (P. granatum L.) (pomegranate) peel extract against Enterobacteriaceae [Escherichia coli (E. coli), Salmonella Typhimurium (S. Typhimurium) and Shigella Dysenteriae (S. Dysenteriae)] and gram-positive bacterium [Staphylococcus aureus (Staph aureus)]. Methanolic extract of P. granatum L. peel was prepared by Soxhlet apparatus method. Total flavonoid and phenolic contents from the extract were determined by High Performance Liquid Chromatography (HPLC). The antibacterial activity of P. granatum L. peel extract was evaluated through agar well diffusion method. HPLC showed the range of phenolics (gallic acid, caffeic acid, benzoic acid, cinnamic acid) and flavonoid compounds. The chemical structures of flavonoid and phenolics found in the methanolic extract of P. granatum L. peel have been reported for the first time. The methanolic peel extract (50 ul) of yellow P. granatum L. showed 26, 10, 10 and 9mm zones of inhibition (ZOI) against S. aureus, S. Typhimurium, S. Dysenteriae and E. coli, respectively. The methanolic extract of red P. granatum L. (100 ul) showed 27, 8, 12 and 15 mm ZOI against Staph. aureus, S. Typhimurium, S. Dysenteriae and E. coli, respectively. Highest ZOI was observed against Staph. aureus. Many of the bacteria studied in the present work may cause serious gastrointestinal infections, which can lead to hemorrhagic diarrhea in children. These [...].(AU)

A tendência crescente na resistência antimicrobiana e na falha dos antibióticos sintetizados quimicamente leva à descoberta de métodos alternativos para o tratamento de infecções bacterianas. Várias plantas medicinais estão em uso tradicionalmente e seus compostos ativos podem ser posteriormente aplicados para o tratamento de doenças bacterianas. Este estudo foi desenhado para determinar a atividade antibacteriana do extrato de casca de Punica granatum (P. granatum L.) (romã) contra Enterobacteriaceae [Escherichia coli (E. coli), Salmonella Typhimurium (S. Typhimurium) e Shigella Dysenteriae (S. Dysenteriae) ] e bactéria gram-positiva [Staphylococcus aureus (Staph aureus)]. O extrato metanólico da casca de P. granatum L. foi preparado pelo método do aparelho de Soxhlet. O conteúdo total de flavonoides e fenólicos do extrato foi determinado por cromatografia líquida de alta eficiência (HPLC). A atividade antibacteriana do extrato da casca de P. granatum L. foi avaliada através do método de difusão em ágar. HPLC mostrou a gama de compostos fenólicos (ácido gálico, ácido cafeico, ácido benzoico, ácido cinâmico) e flavonoides. As estruturas químicas de flavonoides e fenólicos encontradas no extrato metanólico da casca de P. granatum L. foram relatadas pela primeira vez. O extrato metanólico da casca (50 ul) de P. granatum L. amarelo apresentou zonas de inibição (ZOI) de 26, 10, 10 e 9mm contra S. aureus, S. Typhimurium, S. Dysenteriae e E. coli, respectivamente. O extrato metanólico de P. granatum L. vermelho (100 ul) apresentou 27, 8, 12 e 15 mm IOI contra Staph. aureus, S. Typhimurium, S. Dysenteriae e E. coli, respectivamente. O ZOI mais alto foi observado contra Staph. aureus. Muitas das bactérias estudadas no presente trabalho podem causar infecções gastrointestinais graves, que podem levar à diarreia [...].(AU)

In Vitro Antimicrobial Efficacy Assessment of Ethanolic and Aqueous Extracts of Cinnamon (Cinnamomum Verum) Bark against Selected Microbes

To combat pathogens and reduce the major public health problem of antibiotic residues in animal products, scientists are looking for natural antibiotic substitutes that are effective against drug-resistant pathogenic microbes and spoilage fungi. The antimicrobial activity of three Cinnamomum verum extracts prepared with three different solvents (absolute ethanol, 50% ethanol, and aqueous extracts) was determined against two Gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes) and two Gram-negative bacteria (Salmonella Typhimurium and Escherichia coli) as well as two fungal strains. The antimicrobial activities of various Cinnamomum verum extracts against selected microbes were evaluated using the disc diffusion test, minimum inhibitory concentrations (MIC), minimum bactericidal concentrations (MBC), minimum fungicidal concentrations (MFC), and the poisoned food technique. Cinnamomum verum bark (CVB) extracts inhibited and killed microbial growth to varying degrees. Our findings also revealed that extracts prepared with alcoholic solvents, particularly absolute ethanol-CVB extract, were more active compared with aqueous solvents, suggesting that the cinnamon plant is a promising natural antimicrobial agent for food preservation.(AU)

The Efficiency of Bacteriophages Against Salmonella Typhimurium Infection in Native Noi Broilers

Though recently considered a therapeutic treatment for commercial broilers, little is known about the effects of bacteriophages on native, slow-growing birds. This study evaluated their efficacy against Salmonella enterica subsp. enterica serovar Typhimurium infected Noi chicken, a native Vietnamese broiler breed. In total, 420 birds were used in a completely randomized design consisting of seven treatments and four replicates of 15 birds. The treatments were NC (negative control), PC (positive control, S. Typhimurium challenged); NC+B1 and NC+B2 (negative control plus B1 or B2 bacteriophage, respectively); PC+B1, PC+B2 (positive control plus B1 or B2 bacteriophage, respectively) and PC+B1B2 (positive control plus both B1 and B2 bacteriophages). After four weeks of infection, the mortality rate in the PC group was 51.1% compared with 11.1% in the PC+B1B2 treatment. Bacteriophage administration had resulted in increased weight gain and decreased feed conversion ratio, particularly when both phages were included in the treatment (p<0.001). Moreover, the relative percentage of carcass weight was lowest in the PC treatment (66.9%) (p<0.001), whereas the other treatments registered similar carcass weight values. Regarding the internal organs, liver weight percentage was higher in the non-treated Salmonella group, and enlarged spleens were also noted in infected chickens even when treated with bacteriophages. The correlation between phage administration and blood parameters was unclear. Although the use of two bacteriophages for therapy was determined to be preferable for the majority of the criteria examined, further genetic characterization of the phages will be required before they can be widely used in chicken farms.(AU)

Evaluation of the active concentration of two disinfectants based on glutaraldehyde and benzalkonium chloride and antimicrobial activity in vitro against Salmonella Heidelberg and Salmonella Typhimurium

Biosecurity, cleaning and disinfection of swine and poultry facilities are fundamental for the reduction of pathogenic microorganisms of importance for public and animal health. The objective of this work was to compare the levels of active ingredient described on the label and the real levels detected in high-performance liquid chromatography (HPLC) of two disinfectants., then evaluate the antimicrobial activity since, following the Germicidal Sanitizing Action and Disinfectant Detergent (Official Method AOAC 960.09) in four different dilutions with the presence of 3% organic matter during 15 min of contact, against Salmonella Heidelberg and Salmonella Typhimurium (ST). The product "A" presents active levels of agreement according to the label. The content of quantified assets for product "B" was lower than that recorded on the label. The disinfectant "A" was effective in microbiological evaluation while the disinfectant "B" had microbiocidal activity compromised by the deficit of assets.

Prevalence and antimicrobial resistance of Salmonella spp isolated from free-ranging wild boars in the state of São Paulo, Brazil / Prevalência e resistência antimicrobiana de Salmonella spp isoladas em javalis de vida livre no estado de São Paulo

European wild boars (Sus scrofa) are considered exotic invasive species worldwide. Invasions of wild boars are a growing public health concern, as wild boars may represent an important reservoir of zoonotic pathogens, including bacteria of the genus Salmonella. The aim of this study was to determine the prevalence and serovars of Salmonella spp. in free-ranging wild boars legally hunted in the state of São Paulo, Brazil, and the susceptibility of those Salmonella spp. to antimicrobials. Fecal samples and mesenteric lymph nodes were acquired from 63 wild boars. The prevalence of Salmonella spp. in free-ranging wild boars was 9.5 % (6/63; confidence interval: 4.4 % - 19.2 %). Six serovars were isolated: S. enterica subsp. enterica ser. 4,5,12:-:1,2, S. enterica ser. Cerro, S. enterica ser. Madelia, S. enterica ser. Typhimurium, S. enterica ser. I (4,5,12:i:-) and S. enterica ser. Muenster. Analysis of antimicrobial resistance of Salmonella spp. showed that the majority of serovars were fully susceptible to the tested antimicrobials. Only S. enterica ser. Typhimurium and S. enterica ser. Muenster showed a resistance pattern to at least one antimicrobial analyzed. To our knowledge, this study is the first report the prevalence and serovars of Salmonella spp. in free-ranging wild boars in the State of São Paulo, Brazil. Results indicate a low prevalence with variability of Salmonella serovars, with some pattern of antimicrobial resistance. This study highlights the potential role of wild boars as carriers of Salmonella and could pose a risk to wild and domestic animals as well as humans.

Os javalis europeus (Sus scrofa) são considerados uma espécie exótica invasora em todo o mundo. As invasões de javalis são uma preocupação crescente de saúde pública, pois os javalis podem representar um importante reservatório de patógenos zoonóticos, incluindo bactérias do gênero Salmonella. O objetivo deste estudo foi determinar a prevalência e os sorovares de Salmonella spp. em javalis de vida livre caçados legalmente no Estado de São Paulo, Brasil, e a suscetibilidade dessa Salmonella spp. aos antimicrobianos. Amostras fecais e linfonodos mesentéricos foram adquiridos de 63 javalis. A prevalência de Salmonella spp. em javalis selvagens foi de 9,5% (6/63; intervalo de confiança: 4,4% - 19,2%). Seis sorovares foram isolados: S. enterica subsp. enterica ser. 4,5,12:-:1,2, S. enterica ser. Cerro, S. enterica ser. Madelia, S. enterica ser. Typhimurium, S. enterica ser. I (4,5,12:i:-) e S. enterica ser. Muenster. As análises de resistência antimicrobiana de Salmonella spp. evidenciaram que a maioria dos sorovares era pansensível aos antimicrobianos testados. Apenas S. enterica ser. Typhimurium e S. enterica ser. Muenster mostraram um padrão de resistência a pelo menos um antimicrobiano analisado. A saber, este estudo é o primeiro relato da prevalência e de sorovares de Salmonella spp. em javalis de vida livre no Estado de São Paulo, Brasil. Os resultados indicaram baixa prevalência com variabilidade de sorovares de Salmonella, com algum padrão de resistência antimicrobiana. Este estudo destaca o papel potencial dos javalis como portadores de Salmonella spp. e pode representar um risco para os animais domésticos e selvagens, bem como para os humanos.

Probiotic Lactobacilli Improved Growth Performance and Attenuated Salmonella Typhimurium Infection Via Jak/Stat Signaling in Broilers

This study aimed to investigate the effect of Lactobacillus plantarum DPP8 and Lactobacillus acidophilus C7282 in feed supplementation on growth performance, Salmonella invasion, inflammation, and mediating signaling in broilers infected with Salmonella Typhimurium (S. Typhimurium). A total of 240 broilers at day old were randomly allocated into four groups, orally infected with S. Typhimurium and supplemented with individual or combined Lactobacilli DPP8 and C7282 at doses of 0 (control), 1010 (individual), or 2.0 × 1010 (combination) cfu/kg of diet for 21 d. The results showed that supplementing Lactobacilli improved (p 0.05) feed intake and body weight gain and decreased (p 0.05) S. Typhimurium load in the caecum, harder gland, spleen and bursa of Fabricius. Also, the supplements decreased (p 0.05) interleukin (1/2/4), tumor necrosis factor and interferon in the serum, enhanced (p 0.05) interleukin 10, and downregulated gene expressions of inflammatory mediators including Janus kinase (Jak2/3), signal transducer and activator of transcription protein (STAT3/4/5/6) in the intestinal mucosa. In contrast, diets containing DPP8 exhibited greater effects on the inhibition of the pathogen and inflammatory response than C7282. The obtained data suggest that Lactobacilli C7282 and DPP8 can be used as feed additives to inhibit colonization and translocation of S. Typhimurium and inflammatory responses via downregulating Jak/STAT signaling in broilers.(AU)

Probiotic Lactobacilli Improved Growth Performance and Attenuated Salmonella Typhimurium Infection Via Jak/Stat Signaling in Broilers

This study aimed to investigate the effect of Lactobacillus plantarum DPP8 and Lactobacillus acidophilus C7282 in feed supplementation on growth performance, Salmonella invasion, inflammation, and mediating signaling in broilers infected with Salmonella Typhimurium (S. Typhimurium). A total of 240 broilers at day old were randomly allocated into four groups, orally infected with S. Typhimurium and supplemented with individual or combined Lactobacilli DPP8 and C7282 at doses of 0 (control), 1010 (individual), or 2.0 × 1010 (combination) cfu/kg of diet for 21 d. The results showed that supplementing Lactobacilli improved (p 0.05) feed intake and body weight gain and decreased (p 0.05) S. Typhimurium load in the caecum, harder gland, spleen and bursa of Fabricius. Also, the supplements decreased (p 0.05) interleukin (1/2/4), tumor necrosis factor and interferon in the serum, enhanced (p 0.05) interleukin 10, and downregulated gene expressions of inflammatory mediators including Janus kinase (Jak2/3), signal transducer and activator of transcription protein (STAT3/4/5/6) in the intestinal mucosa. In contrast, diets containing DPP8 exhibited greater effects on the inhibition of the pathogen and inflammatory response than C7282. The obtained data suggest that Lactobacilli C7282 and DPP8 can be used as feed additives to inhibit colonization and translocation of S. Typhimurium and inflammatory responses via downregulating Jak/STAT signaling in broilers.

Growth kinetics of Salmonella Typhimurium and Listeria monocytogenes in buffalo milk under different processing and storage conditions / Cinética de crescimento de Salmonella Typhimurium e Listeria monocytogenes em leite bubalino sob diferentes condições de processamento e armazenamento

Buffalo milk is rich in nutrients and can serve as a substrate for the proliferation of microorganisms. Thus, the objective of the present study was to evaluate the growth kinetics of Salmonella Typhimurium and Listeria monocytogenes in buffalo milk under different processing and storage conditions. Samples of raw and pasteurized milk were inoculated with 1 CFU of each bacterium, separately and together, per 25 mL. After contamination, samples were stored at 8 °C or 37 °C, and bacterial counts were performed at 24, 48, and 168 h. In addition, the accompanying microbiota growth, pH, and the effect of these variables on the growth kinetics of microorganisms were monitored. The pathogens tested were able to proliferate under most conditions tested, reaching high titers throughout the experimental period. At 37 °C, there was a decrease in pH and an increase in the accompanying microbiota that interfered with the microbial growth curve. It was also observed that pasteurized milk subjected to 8 °C provided better conditions for the multiplication of bacteria. Therefore, it was concluded that care throughout the production chain, storage, and commercialization of milk must be adopted to guarantee the microbiological safety of this food.

O leite bubalino é rico em nutrientes e pode servir de substrato para a proliferação de micro-organismos. Assim, o objetivo do presente estudo foi avaliar a cinética de crescimento de Salmonella Typhimurium e Listeria monocytogenes em leite bubalino, em diferentes condições de processamento e armazenamento. Para isso, utilizaram-se amostras de leite cru e pasteurizado, que foram inoculadas com 1 UFC/25 mL de cada bactéria separadamente e em conjunto. Após a contaminação, as amostras foram armazenadas nas temperaturas de 8 ºC e 37 ºC e realizadas contagens bacterianas em 24, 48 e 168h. Além disso, foi acompanhado o crescimento da microbiota acompanhante, o pH e o efeito dessas variáveis sobre a cinética de crescimento dos micro-organismos. Os patógenos testados conseguiram se proliferar na maioria das condições testadas, atingindo altos títulos durante todo o período experimental. Na temperatura de 37 ºC, houve uma diminuição do pH e um aumento da microbiota acompanhante, o que interferiu na curva de crescimento microbiana. Observou-se também que o leite pasteurizado e submetido a 8 ºC possibilitou melhores condições para a multiplicação das bactérias. Sendo assim, concluiu-se que cuidados durante toda a cadeia de produção, armazenamento e comercialização do leite devem ser adotados para garantir a segurança microbiológica desse alimento.

Growth kinetics of Salmonella Typhimurium and Listeria monocytogenes in buffalo milk under different processing and storage conditions / Cinética de crescimento de Salmonella Typhimurium e Listeria monocytogenes em leite bubalino sob diferentes condições de processamento e armazenamento

Buffalo milk is rich in nutrients and can serve as a substrate for the proliferation of microorganisms. Thus, the objective of the present study was to evaluate the growth kinetics of Salmonella Typhimurium and Listeria monocytogenes in buffalo milk under different processing and storage conditions. Samples of raw and pasteurized milk were inoculated with 1 CFU of each bacterium, separately and together, per 25 mL. After contamination, samples were stored at 8 °C or 37 °C, and bacterial counts were performed at 24, 48, and 168 h. In addition, the accompanying microbiota growth, pH, and the effect of these variables on the growth kinetics of microorganisms were monitored. The pathogens tested were able to proliferate under most conditions tested, reaching high titers throughout the experimental period. At 37 °C, there was a decrease in pH and an increase in the accompanying microbiota that interfered with the microbial growth curve. It was also observed that pasteurized milk subjected to 8 °C provided better conditions for the multiplication of bacteria. Therefore, it was concluded that care throughout the production chain, storage, and commercialization of milk must be adopted to guarantee the microbiological safety of this food.(AU)

O leite bubalino é rico em nutrientes e pode servir de substrato para a proliferação de micro-organismos. Assim, o objetivo do presente estudo foi avaliar a cinética de crescimento de Salmonella Typhimurium e Listeria monocytogenes em leite bubalino, em diferentes condições de processamento e armazenamento. Para isso, utilizaram-se amostras de leite cru e pasteurizado, que foram inoculadas com 1 UFC/25 mL de cada bactéria separadamente e em conjunto. Após a contaminação, as amostras foram armazenadas nas temperaturas de 8 ºC e 37 ºC e realizadas contagens bacterianas em 24, 48 e 168h. Além disso, foi acompanhado o crescimento da microbiota acompanhante, o pH e o efeito dessas variáveis sobre a cinética de crescimento dos micro-organismos. Os patógenos testados conseguiram se proliferar na maioria das condições testadas, atingindo altos títulos durante todo o período experimental. Na temperatura de 37 ºC, houve uma diminuição do pH e um aumento da microbiota acompanhante, o que interferiu na curva de crescimento microbiana. Observou-se também que o leite pasteurizado e submetido a 8 ºC possibilitou melhores condições para a multiplicação das bactérias. Sendo assim, concluiu-se que cuidados durante toda a cadeia de produção, armazenamento e comercialização do leite devem ser adotados para garantir a segurança microbiológica desse alimento.(AU)

Avaliação in vitro de atividade antimicrobiana de óleos essenciais contra Salmonella typhimurium e Staphylococcus aureus / In vitro evaluation of antimicrobial activity of essential oils against Salmonella typhimurium and Staphylococcus aureus

O objetivo do trabalho foi avaliar a atividade antimicrobiana in vitro de diferentes óleos essenciais e suas combinações contra linhagens patogênicas de Salmonella typhimurium ATCC 13311 e Staphylococcus aureus ATCC 13565. Foram testados ao todo 41 óleos essenciais e as combinações em pares dos óleos de alecrim-pimenta (Lippia sidoides Cham.), capim-limão (Cymbopogon citratus Stapf.), tomilho (Thymus vulgaris L.), orégano (Origanum vulgare L.) e canela (Cinnamomum cassia (L.) D.Don. para observar efeitos adicionais ou não na inibição dos microrganismos. Os resultados mostraram que as melhores atividades antimicrobianas para os dois microrganismos foram obtidas utilizando os óleos de Thymus vulgaris L. (tomilho), Origanum vulgare L. (orégano) e Lippia sidoides Cham. (alecrim-pimenta). As combinações de cada par dos óleos de alecrim-pimenta, capim-limão, tomilho, orégano e canela não apresentaram uma melhora adicional no efeito para os patógenos estudados quando comparados com os seus óleos testados isoladamente. As composições químicas dos óleos essenciais mais ativos foram obtidas por meio de análises por cromatografia gasosa acoplada à espectrometria de massas (CG-EM), sendo que os compostos majoritários do óleo de orégano foram carvacrol (69,1%) e p-cimeno (18,8%), do óleo essencial de tomilho foram timol (45,5%) e p-cimeno (35,6%) e do alecrim-pimenta foram o timol (77,2%) e p-cimeno (14,2%). Análises quantitativas de p-cimeno, carvacrol e timol nos três óleos foram realizadas e comparadas com as composições químicas mostrando resultados proporcionalmente coerentes, exceto para p-cimeno, que foi quantificado com menores porcentagens por esse método. A aplicabilidade dos óleos selecionados, ou das substâncias presentes isoladas seria diretamente nos alimentos, com a finalidade de inibir ou controlar o crescimento desses patógenos, contribuindo assim para a segurança dos alimentos. (AU)

The aim of this study was to evaluate the in vitro antimicrobial activity of several essential oils and their combination against pathogenic strains of Salmonella typhimurium ATCC 13311 and Staphylococcus aureus ATCC 13565. A total of 41 essential oils and the combinations in pairs of the oils of rosemary pepper (Lippia sidoides Cham.), lemongrass (Cymbopogon citratus Stapf.), thyme (Thymus vulgaris L.), origanum (Origanum vulgare L.) and cinnamon (Cinnamomum cassia (L.) D.Don) were tested to observe additional effects or not in the inhibition of microorganisms. The results showed that the best antimicrobial activities for the two microorganisms were obtained using the oils of Thymus vulgaris L. (thyme), Origanum vulgare L. (origanum) and Lippia sidoides Cham. (rosemary pepper). The combinations of each pair of rosemary pepper, lemongrass, thyme, origanum and cinnamon oils did not show any further improvement in the effect for the studied pathogens when compared to their oils tested alone. The compositions of the most active essential oils were obtained by gas chromatography coupled to mass spectrometry (GC-MS). The major compounds in origanum oil were carvacrol (69.1%) and p-cymene (18.8%), thyme essential oil were thymol (45.5%) and p-cymene (35.6%) and rosemary pepper were thymol (77.2%) and p-cymene (14.2%). Quantitative analyses of p-cymene, carvacrol and thymol confirmed the presence in thyme, oregano and pepper rosemary oils and were compared with the chemical composition showing similar results, except for p-cymene, which was quantified with lower percentages in these oils. One of the possible applications of the results of this work is the use of essential oils, or the isolated substances, directly in foods, with the purpose of inhibiting or controlling the growth of these pathogens, thus contributing to the food safety.Keywords: Bioassay. GC-MS. Inhibition. Carvacrol. Thymol. p-cymene(AU)

Growth kinetics of Salmonella Typhimurium and Listeria monocytogenes in buffalo milk under different processing and storage conditions / Cinética de crescimento de Salmonella Typhimurium e Listeria monocytogenes em leite bubalino sob diferentes condições de processamento e armazenamento

ABSTRACT: Buffalo milk is rich in nutrients and can serve as a substrate for the proliferation of microorganisms. Thus, the objective of the present study was to evaluate the growth kinetics of Salmonella Typhimurium and Listeria monocytogenes in buffalo milk under different processing and storage conditions. Samples of raw and pasteurized milk were inoculated with 1 CFU of each bacterium, separately and together, per 25 mL. After contamination, samples were stored at 8 °C or 37 °C, and bacterial counts were performed at 24, 48, and 168 h. In addition, the accompanying microbiota growth, pH, and the effect of these variables on the growth kinetics of microorganisms were monitored. The pathogens tested were able to proliferate under most conditions tested, reaching high titers throughout the experimental period. At 37 °C, there was a decrease in pH and an increase in the accompanying microbiota that interfered with the microbial growth curve. It was also observed that pasteurized milk subjected to 8 °C provided better conditions for the multiplication of bacteria. Therefore, it was concluded that care throughout the production chain, storage, and commercialization of milk must be adopted to guarantee the microbiological safety of this food.

RESUMO: O leite bubalino é rico em nutrientes e pode servir de substrato para a proliferação de micro-organismos. Assim, o objetivo do presente estudo foi avaliar a cinética de crescimento de Salmonella Typhimurium e Listeria monocytogenes em leite bubalino, em diferentes condições de processamento e armazenamento. Para isso, utilizaram-se amostras de leite cru e pasteurizado, que foram inoculadas com 1 UFC/25 mL de cada bactéria separadamente e em conjunto. Após a contaminação, as amostras foram armazenadas nas temperaturas de 8 ºC e 37 ºC e realizadas contagens bacterianas em 24, 48 e 168h. Além disso, foi acompanhado o crescimento da microbiota acompanhante, o pH e o efeito dessas variáveis sobre a cinética de crescimento dos micro-organismos. Os patógenos testados conseguiram se proliferar na maioria das condições testadas, atingindo altos títulos durante todo o período experimental. Na temperatura de 37 ºC, houve uma diminuição do pH e um aumento da microbiota acompanhante, o que interferiu na curva de crescimento microbiana. Observou-se também que o leite pasteurizado e submetido a 8 ºC possibilitou melhores condições para a multiplicação das bactérias. Sendo assim, concluiu-se que cuidados durante toda a cadeia de produção, armazenamento e comercialização do leite devem ser adotados para garantir a segurança microbiológica desse alimento.

Validation of Alternative Methods of Detection of Salmonella Spp. in Experimentally Contaminated Poultry Environmental Samples

The analysis of Salmonella in the feces and the birds environment is a way of monitoring the colonization in the flocks and verifying the need for the introduction of stricter controls, in such a way that the results of the tests should be known before being sent for slaughter. The polymerase chain reaction (PCR), as well as other rapid methods represent alternatives increasingly used to detect enteric pathogens, but they need proof of effectiveness for their wide use. The aim of this study was to evaluate the equivalence between the results obtained by the methods: real-time PCR (BAX® System), Modified Rappaport-Vassiliadis Semi-solid Medium (MSRV) (ISO 6579) and the traditional method of official reference in Brazil for research of S. Typhimurium and S. Enteritidis in poultry samples. Two hundred and fifty-two samples of disposable shoe covers (DSC) and 252 samples of feces were infected with an average of 2 to 3 log CFU/g of each serovar, and the same samples without fortification were evaluated by the three methods. Five hundred and four diagnoses were obtained with satisfactory results in terms of repeatability (greater than 80%), reproducibility (mean 83,1%), sensitivity (81% to 100%), specificity (95% to 100%), and accuracy (90% to 100%). The compliance test verified that there was not a significant difference between the alternative and the official methods, allowing us to state that the methodologies have had equivalent performances.(AU)