Grapevine stilbenoids as natural food preservatives: calorimetric and spectroscopic insights on the interaction with model cell membranes

2021 ◽  
Author(s):  
Francesca Saitta ◽  
Stefania Mazzini ◽  
Luce M Mattio ◽  
Marco Signorelli ◽  
S. Dallavalle ◽  
...  

Food contamination with pathogenic microorganisms, such as Listeria monocytogenes, Salmonella enterica, Staphylococcus aureus and Bacillus cereus, is a common health concern. Natural product, which have been the main source of...

2008 ◽  
Vol 71 (2) ◽  
pp. 325-332 ◽  
Author(s):  
YONG-SUK KIM ◽  
ZIAN-BIN ZHENG ◽  
DONG-HWA SHIN

Kimchi is a unique Korean traditional vegetable product that is fermented by lactic acid bacteria (LAB) and is mainly consumed as a side dish with boiled rice. Its main ingredients are brined Chinese cabbage, red pepper powder, and fermented fish sauce, and these are combined with many spices such as garlic, green onion, ginger, and some seaweed. The relationship between the concentration of LAB or the pH and the growth of three gram-positive foodborne pathogens (Bacillus cereus, Listeria monocytogenes, and Staphylococcus aureus) was evaluated. Heat treatment (HT; 85°C for 15 min) or neutralization treatment (NT; pH 7.0) was conducted on day 0 (0-D group) and day 3 (3-D group) of incubation. The pH in the control group and the NT group dropped sharply to 4.12 to 4.30 after 2 days of incubation and slightly decreased thereafter, whereas the pH in the control group and HT group stayed at 7.0 during incubation. LAB were not detected in the HT kimchi during incubation. B. cereus in the NT-0-D, NT-3-D, and HT-3-D groups was reduced by 1.5 to 3.1 log CFU/ml but increased slightly in the HT-0-D group. L. monocytogenes in HT-3-D and NT-3-D groups disappeared after 5 days of incubation, and S. aureus in the NT-0-D group disappeared after 4 days. These findings indicate that growth of all the foodborne pathogens was inhibited by NT-0-D, HT-3-D, and NT-3-D, but B. cereus was not inhibited by HT-0-D. Thus, growth of LAB in kimchi is an important factor in the control of foodborne pathogens.


2007 ◽  
Vol 20 (2) ◽  
pp. 139-148 ◽  
Author(s):  
Miriam Isabel Souza dos Santos Simon ◽  
Susette Freimüller ◽  
Eduardo César Tondo ◽  
Anelise Siviero Ribeiro ◽  
Michele Drehmer

OBJETIVOS: Avaliar a qualidade microbiológica e a temperatura de dietas enterais antes e após a implementação do sistema Análise de Perigos e Pontos Críticos de Controle na Central de Produção de Alimentação Enteral do Hospital de Clínicas de Porto Alegre. MÉTODOS: Durante o período de setembro de 2001 a janeiro de 2002, foram coletadas 320 amostras de 4 tipos de dietas enterais produzidas na Central de Produção de Alimentação Enteral (dietas padrão I, II, III e dieta especial), as quais foram submetidas a análises microbiológicas e de temperatura. As amostras foram coletadas semanalmente em dois pontos do processo: logo após o preparo e após 16 horas de armazenamento refrigerado. Para comparação dos dados pré e pós análise dos perigos em pontos criticos e de controle, utilizou-se o teste "t" de Wilcoxon para amostras pareadas (teste não-paramétrico equivalente ao teste "t" de Student para amostras pareadas) com nível de significância de 0,05. RESULTADOS: Antes da análise de perigos e pontos críticos de controle, 92% das temperaturas de armazenamento estavam acima dos valores de refererência vigentes. Após a implantação da análise de perigos e pontos críticos de controle, houve reduções significantes (p<0,05) nas contagens de microrganismos mesófilos totais das dietas II, III e Especial, logo após preparo. Reduções significantes também foram encontradas nas dietas II e III armazenadas sob refrigeração. Não foram encontrados coliformes fecais, Staphylococcus aureus, Bacillus cereus, Clostridium sulfito redutores, Salmonella sp., Yersinia enterocolitica ou Listeria monocytogenes em nenhum dos momentos avaliados. A análise crítica do fluxograma de produção identificou as etapas de aquisição de matéria-prima e de armazenamento sob refrigeração como Pontos Críticos de Controle das dietas produzidas. CONCLUSÃO: Com a implantação deste sistema na central de produção de alimentação enteral foram realizadas mudanças que contribuíram significativamente na qualidade do produto final, diminuindo riscos de contaminação alimentar.


2019 ◽  
Vol 8 (4) ◽  
Author(s):  
Francesca Pedonese ◽  
Giada Verani ◽  
Beatrice Torracca ◽  
Barbara Turchi ◽  
Antonio Felicioli ◽  
...  

Propolis antimicrobial activity has been limitedly studied in food, particularly in dairy products. We studied the antimicrobial activity of an alcoholic extract of an Italian propolis in sterile skim milk, pasteurized cow’s milk, and cow’s and goat’s whey cheese (ricotta). Following the determination of the minimal inhibitory concentration on Gram+ and Gram- bacteria, the extract was employed at 2 and 5% (P2, P5), using controls with the same ethanol concentrations (E2, E5) and without any addition. In milk trials, Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, and Pseudomonas fluorescens were tested. P2 and P5 samples registered significant decreases of Gram+ bacteria in skim milk. The same was true for P5 in cows’ milk, but only with S. aureus for P2. Ricotta was inoculated with L. monocytogenes, S. aureus and B. cereus and stored at 8.5°C. In cow’s milk ricotta, L. monocytogenes counts in P5 were always lower than control during the storage time, significantly so from the 14th day. In goat’s ricotta, L. monocytogenes counts in P5 were at least one logarithm lower than E5, whereas the extract didn’t show a significant effect on S. aureus and B. cereus. The antimicrobial activity of propolis, particularly on L. monocytogenes, could be employed in ready-to-eat refrigerated dairy products.


2021 ◽  
Author(s):  
Qiong Huang

Food poisoning caused by microorganisms has caused widespread concern. Herein, a highly sensitive on-site screening test strip for the detection of different pathogenic microorganisms (Listeria monocytogenes and Staphylococcus aureus) was...


2003 ◽  
Vol 58 (11-12) ◽  
pp. 850-854 ◽  
Author(s):  
Ayşen Özdemir Türk ◽  
Meral Yılmaz ◽  
Merih Kıvanç ◽  
Hayrettin Türk

Abstract In this study, the antimicrobial activity of the acetone, diethyl ether and ethanol extracts of the lichen Cetraria aculeata has been investigated. The extracts were tested against twelve bacteria and eight fungi and found active against Escherichia coli, Staphylococcus aureus, Aeromonas hydrophila, Proteus vulgaris, Streptococcus faecalis, Bacillus cereus, Bacillus subtilis, Pseudomonas aeruginosa, Listeria monocytogenes. No antimicrobial activity against the fungi was detected. It was determined that only one substance in the extracts has antimicrobial activity and it was characterized as protolichesterinic acid. The MICs of the extracts and protolichesterinic acid were also determined.


2016 ◽  
Vol 79 (5) ◽  
pp. 810-815 ◽  
Author(s):  
FEREIDOUN FORGHANI ◽  
SHUAI WEI ◽  
DEOG-HWAN OH

ABSTRACTThree important foodborne pathogens, Bacillus cereus, Listeria monocytogenes, and Staphylococcus aureus, are of great concern for food safety. They may also coexist in food matrices and, in the case of B. cereus and S. aureus, the resulting illnesses can resemble each other owing to similar symptoms. Therefore, their simultaneous detection may have advantages in terms of cost savings and rapidity. Given this context, a rapid multiplex real-time PCR high-resolution melt curve assay for the simultaneous detection of these three pathogens in food was developed. The assay successfully detected B. cereus (gyrB), L. monocytogenes (hly), and S. aureus (nuc) in a single reaction, and the average melting temperatures were 76.23, 80.19, and 74.01°C, respectively. The application of SYTO9 dye and a slow melt curve analysis ramp rate (0.1°C/s) enabled the production of sharp, high-resolution melt curve peaks that were easily distinguishable from each other. The detection limit in food (milk, rice, and lettuce) was 3.7 × 103 CFU/g without an enrichment step and 3.7 × 101 CFU/g following the 10-h enrichment. Hence, the assay developed here is specific and sensitive, providing an efficient tool for implementation in food for the simultaneous detection of B. cereus, L. monocytogenes, and S. aureus.


2009 ◽  
Vol 58 (5) ◽  
pp. 577-583 ◽  
Author(s):  
T. D. Kalyan Kumar ◽  
K. Balakrishna ◽  
H. S. Murali ◽  
H. V. Batra

Haemolysin BL (HBL) of Bacillus cereus, listeriolysin O (LLO) of Listeria monocytogenes and enterotoxin B (SEB) of Staphylococcus aureus are among the major toxin components contributing to the pathogenicity of these organisms in foodborne illnesses. In this study, an intergenus non-toxic multidomain fusion protein (r-HLE) was generated with specificity for HBL, LLO and SEB. The fusion gene (r-hle) comprising the conserved regions of hblD and the hly and entB genes was codon-optimized for expression in Escherichia coli and encoded a 50 kDa recombinant multidomain chimeric protein (r-HLE). Hyperimmune antiserum raised against r-HLE specifically reacted with the L1 (38 kDa) component of the HBL complex of B. cereus, LLO (58 kDa) of L. monocytogenes and SEB (28 kDa) of S. aureus during Western blot analysis when tested on standard strains. During testing on isolates, the antiserum again identified the appropriate toxin molecules and was highly specific to the relevant bacterial species. The antigenicity of the SEB component of the r-HLE protein was also confirmed using a commercially available TECRA kit. The described procedure of creating a single antigenic molecule carrying components of three different toxins whilst still retaining the original antigenic determinants of individual toxins will be highly advantageous in the development of rapid, reliable and cost-effective immunoassays.


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