Veterinária
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11842
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Resultados da Pesquisa
Item Occurrence and characterization of Listeria monocytogenes from beef jerky processing line(Journal of Food Science and Technology, 2019-01) Silva, Danilo Augusto Lopes da; Nero, Luís Augusto; Coradini, Marcia Goulart Lopes; Maia, Darla Silveira Volcan; Iglesias, Mariana Almeida; Haubert, Louise; Lopes, Graciela VolzBeef jerky is a ready-to-eat product that does not require refrigeration at the point of sale. Here, we evaluated the occurrence of Listeria monocytogenes in the production process of beef jerky, the presence of virulence genes and the genomic relatedness of the isolates, to assess the safety of the final product. The raw material, surfaces with and without contact with the product and the final product were evaluated along the beef jerky processing line. The samples were evaluated by VIDAS immunoassay system, and the L. monocytogenes isolates were confirmed and evaluated for the presence of several virulence genes by PCR. Listeria monocytogenes was identified in six of the 84 samples (7.14%), and no genetic relationship was observed among isolates. Samples of raw material (2/7), food contact surface (1/56), and work surfaces without contact with food (3/14) presented contamination by L. monocytogenes. The final product was not contaminated, demonstrating that barriers to multiplication of pathogens used during the production process were effective for its control.Item Low occurrence of Salmonella in the beef processing chain from Minas Gerais state, Brazil: From bovine hides to end cuts(Food Control, 2014-06) Cossi, Marcus Vinícius Coutinho; Burin, Raquel Cristina Konrad; Camargo, Anderson Carlos; Dias, Mariane Rezende; Lanna, Frederico Germano Piscitelli Alvarenga; Pinto, Paulo Sérgio de Arruda; Nero, Luís AugustoThe present study aimed to track possible contamination sources of Salmonella spp. during bovine slaughtering. Three slaughterhouses located in Minas Gerais state, Brazil were selected and 836 samples were obtained by surface swabbing of 209 bovine carcasses at four steps of slaughtering: I) after bleeding (from the hide), II) after skinning, III) after evisceration, and IV) after end washing (performed with cold water). Samples were subjected to Salmonella spp. detection according to ISO 6975, and the suspected isolates were identified by PCR as Salmonella by targeting the ompC gene and performing serotyping. Twenty isolates were confirmed as Salmonella and subjected to XbaI macrorestriction and pulsed-field gel electrophoresis (PFGE). Salmonella spp. was detected in the hides of six animals, during slaughtering after skinning (one carcass), after evisceration (two carcasses), and after end washing (three carcasses). Isolates were serotyped as S. Dublin (n = 7), S. Derby (n = 8), S. Infantis (n = 1), S. Give (n = 1), and S. salamae subsp. salamae (n = 3). PFGE demonstrated identical Salmonella pulse-types from hides and slaughtering steps of skinning and evisceration, as well as from animal hides obtained from distinct slaughterhouses. The obtained data indicate a low prevalence of Salmonella spp. during bovine slaughtering in selected industries from Minas Gerais state, Brazil, but identified possible routes of contamination of pathogenic serotypes.Item Genetic diversity and some aspects of antimicrobial activity of lactic acid bacteria isolated from goat milk(Applied Biochemistry and Biotechnology, 2015-01-31) Cavicchioli, Valéria Quintana; Dornellas, Wesley dos Santos; Perin, Luana Martins; Pieri, Fábio Alessandro; Franco, Bernadette Dora Gombossy de Melo; Todorov, Svetoslav Dimitrov; Nero, Luís AugustoLactic acid bacteria (LAB, n = 57) were previously obtained from raw goat milk, identified as Lactococcus spp. (n = 24) and Enterococcus spp. (n = 33), and characterized as bacteriocinogenic. Fingerprinting by pulsed field gel electrophoresis (PFGE) demonstrated high genetic diversity, and 30 strains were selected and exhibited strong antimicrobial activity against 46 target strains (LAB, spoilage, and foodborne pathogens). Six strains (Lactococcus lactis: GLc03 and GLc05; and Enterococcus durans: GEn09, GEn12, GEn14, and GEn17) were selected to characterize their bacteriocinogenic features, using Listeria monocytogenes ATCC 7644 as the target. The six strains produced bacteriocins at higher titer when incubated in MRS at 37 °C up to 12 h, when compared to growth at 25 and 30 °C. The produced bacteriocins kept their antimicrobial activity after exposure to 100 °C for 2 h and 121 °C for 20 min; the antimicrobial activity was also observed after treatment at pH 2.0 to 10.0, except for GLc03. L. monocytogenes populations were reduced approximately two logs after treatment with cell-free supernatants from the selected strains. These data show that goat milk can contain a diverse microbiota able to inhibit L. monocytogenes, a common pathogen found in dairy products, and can be potentially employed in biopreservation of food produced under different processing conditions.Item Molecular tracking of Salmonella spp. in chicken meat chain: from slaughterhouse reception to end cuts(Journal of Food Science and Technology, 2015-12-17) Dias, Mariane Rezende; Cavicchioli, Valéria Quintana; Camargo, Anderson Carlos; Lanna, Frederico Germano Piscitelli Alvarenga; Alvarenga, Frederico Germano Piscitelli; Bersot, Luciano dos Santos; Nero, Luís AugustoDue to the importance of Salmonella spp. in poultry products, this study aimed to track its main contamination routes since slaughtering reception to processing of chicken end cuts. Samples from different steps of slaughtering and processing (n = 277) were collected from two chicken slaughterhouses (Sl1 and Sl2) located in Minas Gerais state, Brazil, and subjected to Salmonella spp. detection. The obtained isolates were subjected to serological identification and tested by PCR for specific Salmonella spp. genes (ompC and sifB). Also, Salmonella spp. isolates were subjected to XbaI macrorestriction and pulsed-field gel electrophoresis (PFGE). Sixty-eight samples were positive for Salmonella spp. and 172 isolates were obtained. Sl1 and Sl2 presented similar frequencies of Salmonella spp. positive samples during reception, slaughtering and processing (p > 0.05), except for higher frequencies in Sl1 for chicken carcasses after de-feathering and evisceration (p < 0.05). PFGE allowed the identification of cross contamination and persistence of Salmonella spp. strains in Sl1. The results highlighted the relevance of the initial steps of chicken slaughtering for Salmonella spp. contamination, and the pre-chilling of carcasses as an important controlling tool. In addition, the presence of Salmonella spp. in chicken end cuts samples represents a public health concern.Item PFGE characterisation and adhesion ability of Listeria monocytogenes isolates obtained from bovine carcasses and beef processing facilities(Meat Science, 2012-12) Galvão, Newton Nascentes; Chiarini, Eb; Destro, Maria Teresa; Ferreira, Márcia de Aguiar; Nero, Luís AugustoListeria monocytogenes is a pathogen capable of adhering to many surfaces and forming biofilms, which may explain its persistence in food processing environments. This study aimed to genetically characterise L. monocytogenes isolates obtained from bovine carcasses and beef processing facilities and to evaluate their adhesion abilities. DNA from 29 L. monocytogenes isolates was subjected to enzymatic restriction digestion (AscI and ApaI), and two clusters were identified for serotypes 4b and 1/2a, with similarities of 48% and 68%, respectively. The adhesion ability of the isolates was tested considering: inoculum concentration, culture media, carbohydrate source, NaCl concentration, incubation temperature, and pH. Each isolate was tested at 10⁸ CFU mL⁻¹ and classified according to its adhesion ability as weak (8 isolates), moderate (17) or strong (4). The isolates showed higher adhesion capability in non-diluted culture media, media at pH 7.0, incubation at 25°C and 37 °C, and media with NaCl at 5% and 7%. No relevant differences were observed for adhesion ability with respect to the carbohydrate source. The results indicated a wide diversity of PFGE profiles of persistent L. monocytogenes isolates, without relation to their adhesion characteristics. Also, it was observed that stressing conditions did not enhance the adhesion profile of the isolates.Item PFGE characterisation and adhesion ability of Listeria monocytogenes isolates obtained from bovine carcasses and beef processing facilities Author links open overlay panel(Meat Science, 2012-06-09) Galvão, Newton Nascentes; Chiarini, Eb; Destro, Maria Teresa; Ferreira, Márcia de Aguiar; Nero, Luís AugustoListeria monocytogenes is a pathogen capable of adhering to many surfaces and forming biofilms, which may explain its persistence in food processing environments. This study aimed to genetically characterise L. monocytogenes isolates obtained from bovine carcasses and beef processing facilities and to evaluate their adhesion abilities. DNA from 29 L. monocytogenes isolates was subjected to enzymatic restriction digestion (AscI and ApaI), and two clusters were identified for serotypes 4b and 1/2a, with similarities of 48% and 68%, respectively. The adhesion ability of the isolates was tested considering: inoculum concentration, culture media, carbohydrate source, NaCl concentration, incubation temperature, and pH. Each isolate was tested at 108 CFU mL− 1 and classified according to its adhesion ability as weak (8 isolates), moderate (17) or strong (4). The isolates showed higher adhesion capability in non-diluted culture media, media at pH 7.0, incubation at 25 °C and 37 °C, and media with NaCl at 5% and 7%. No relevant differences were observed for adhesion ability with respect to the carbohydrate source. The results indicated a wide diversity of PFGE profiles of persistent L. monocytogenes isolates, without relation to their adhesion characteristics. Also, it was observed that stressing conditions did not enhance the adhesion profile of the isolates.