Estrategias de intervención para mitigar el impacto...
Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens that can cause bloody diarrhea, hemorrhagic colitis and hemolytic uremic syndrome. The meat contaminated with STEC impacts on the public health due to the risk of making the\nconsumer sick and on the economy due to the loss implie...
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| Formato: | Tesis doctoral acceptedVersion |
| Lenguaje: | Español |
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Universidad de Buenos Aires. Facultad de Ciencias Veterinarias
2021
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| Acceso en línea: | http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=avaposgra&cl=CL1&d=HWA_7021 https://repositoriouba.sisbi.uba.ar/gsdl/collect/avaposgra/index/assoc/HWA_7021.dir/7021.PDF |
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I28-R145-HWA_7021 |
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dspace |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-145 |
| collection |
Repositorio Digital de la Universidad de Buenos Aires (UBA) |
| language |
Español |
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spa |
| topic |
STEC Carne bovina Irradiación gamma Carne vacuna Acidos orgánicos Escherichia coli Toxina Shiga Industria cárnica Radiación gamma Tecnología de los alimentos |
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STEC Carne bovina Irradiación gamma Carne vacuna Acidos orgánicos Escherichia coli Toxina Shiga Industria cárnica Radiación gamma Tecnología de los alimentos Cap, Mariana Estrategias de intervención para mitigar el impacto... |
| topic_facet |
STEC Carne bovina Irradiación gamma Carne vacuna Acidos orgánicos Escherichia coli Toxina Shiga Industria cárnica Radiación gamma Tecnología de los alimentos |
| description |
Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens that can cause bloody diarrhea, hemorrhagic colitis and hemolytic uremic syndrome. The meat contaminated with STEC impacts on the public health due to the risk of making the\nconsumer sick and on the economy due to the loss implied by the rejection of\ncontaminated meat destined for export. In this context, there is a strong demand to\nevaluate the effectiveness of the antimicrobial treatments available in the country against native STEC O157 and non-O157 strains. The aim of the present study was to evaluate, standardize and promote intervention strategies to reduce the presence of STEC O157 and non-O157 in beef cuts, beef trimmings (raw material for beef burger preparation)\nand ground beef. For that matter, we conducted three assays. In assay 1, we evaluated the efficacy of lactic acid (LA), peroxiacetic acid (PA), caprylic acid (CA) and electrolyzed water (EW) to reduce STEC in beef cuts. In assay 2, we evaluated the efficacy of LA,\nCA and gamma irradiation, alone and combined, to reduce STEC in beef trimmings. In assay 3, we evaluated the efficacy of gamma irradiation to reduce STEC in ground beef.\nIn the 3 assays, the effects on the sensory attributes of the most effective interventions on the different meat matrices analyzed were evaluated, and in assays 1 and 2 the effects on physicochemical parameters were also evaluated. The inoculum consisted in a cocktail of native STEC strains that belonged to the following serogroups: O26, O103, O111, O145 and O157. Samples were inoculated with two bacterial concentrations, high\nand low. Samples with high inoculum (HI) were analyzed by plate count while samples\nwith low inoculum (LI) were analyzed by real-time PCR after an enrichment step.\nEffectiveness was estimated in terms of log reductions for samples with HI and in terms of reduction of the percentages of positive samples for stx and eae genes in samples with LI. Results from assay 1 demonstrated that from the four interventions evaluated,\nonly CA was effective to reduce STEC. The achieved reductions were 0.8 log CFU/g in samples with HI and 77% in samples with LI. Results from assay 2 demonstrated that the most effective treatment to reduce STEC was 2 kGy of gamma irradiation as the\nreduction was higher than 5 log CFU/g in samples with HI and of 100% in samples with LI. The combined treatment of LA and gamma irradiation increased STEC lethality in\nsamples with HI but not in samples with LI. Results from assay 3, demonstrated that 1 kGy was enough to reduce 5 log CFU/g in ground beef samples with HI. However, when samples with LI were subjected to that dose it did not achieve a total STEC inactivation.\nThe results of the present study demonstrate the importance of assessing antimicrobial treatments with more than one level of inoculum. Furthermore, increase the knowledge about different strategies to reduce STEC contamination in beef products without\nsignificantly affecting nor physicochemical characteristics neither sensory attributes |
| author2 |
Vaudagna, Sergio |
| author_facet |
Vaudagna, Sergio Cap, Mariana |
| format |
Tesis doctoral Tesis doctoral acceptedVersion |
| author |
Cap, Mariana |
| author_sort |
Cap, Mariana |
| title |
Estrategias de intervención para mitigar el impacto... |
| title_short |
Estrategias de intervención para mitigar el impacto... |
| title_full |
Estrategias de intervención para mitigar el impacto... |
| title_fullStr |
Estrategias de intervención para mitigar el impacto... |
| title_full_unstemmed |
Estrategias de intervención para mitigar el impacto... |
| title_sort |
estrategias de intervención para mitigar el impacto... |
| publisher |
Universidad de Buenos Aires. Facultad de Ciencias Veterinarias |
| publishDate |
2021 |
| url |
http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=avaposgra&cl=CL1&d=HWA_7021 https://repositoriouba.sisbi.uba.ar/gsdl/collect/avaposgra/index/assoc/HWA_7021.dir/7021.PDF |
| work_keys_str_mv |
AT capmariana estrategiasdeintervencionparamitigarelimpacto AT capmariana estrategiasdeintervencionparamitigarelimpactodeescherichiacoliproductordetoxinashigaenlacadenacarnicabovina |
| _version_ |
1824356458901274624 |
| spelling |
I28-R145-HWA_70212024-08-27 Estrategias de intervención para mitigar el impacto... Shiga toxin-producing Escherichia coli (STEC) are foodborne pathogens that can cause bloody diarrhea, hemorrhagic colitis and hemolytic uremic syndrome. The meat contaminated with STEC impacts on the public health due to the risk of making the\nconsumer sick and on the economy due to the loss implied by the rejection of\ncontaminated meat destined for export. In this context, there is a strong demand to\nevaluate the effectiveness of the antimicrobial treatments available in the country against native STEC O157 and non-O157 strains. The aim of the present study was to evaluate, standardize and promote intervention strategies to reduce the presence of STEC O157 and non-O157 in beef cuts, beef trimmings (raw material for beef burger preparation)\nand ground beef. For that matter, we conducted three assays. In assay 1, we evaluated the efficacy of lactic acid (LA), peroxiacetic acid (PA), caprylic acid (CA) and electrolyzed water (EW) to reduce STEC in beef cuts. In assay 2, we evaluated the efficacy of LA,\nCA and gamma irradiation, alone and combined, to reduce STEC in beef trimmings. In assay 3, we evaluated the efficacy of gamma irradiation to reduce STEC in ground beef.\nIn the 3 assays, the effects on the sensory attributes of the most effective interventions on the different meat matrices analyzed were evaluated, and in assays 1 and 2 the effects on physicochemical parameters were also evaluated. The inoculum consisted in a cocktail of native STEC strains that belonged to the following serogroups: O26, O103, O111, O145 and O157. Samples were inoculated with two bacterial concentrations, high\nand low. Samples with high inoculum (HI) were analyzed by plate count while samples\nwith low inoculum (LI) were analyzed by real-time PCR after an enrichment step.\nEffectiveness was estimated in terms of log reductions for samples with HI and in terms of reduction of the percentages of positive samples for stx and eae genes in samples with LI. Results from assay 1 demonstrated that from the four interventions evaluated,\nonly CA was effective to reduce STEC. The achieved reductions were 0.8 log CFU/g in samples with HI and 77% in samples with LI. Results from assay 2 demonstrated that the most effective treatment to reduce STEC was 2 kGy of gamma irradiation as the\nreduction was higher than 5 log CFU/g in samples with HI and of 100% in samples with LI. The combined treatment of LA and gamma irradiation increased STEC lethality in\nsamples with HI but not in samples with LI. Results from assay 3, demonstrated that 1 kGy was enough to reduce 5 log CFU/g in ground beef samples with HI. However, when samples with LI were subjected to that dose it did not achieve a total STEC inactivation.\nThe results of the present study demonstrate the importance of assessing antimicrobial treatments with more than one level of inoculum. Furthermore, increase the knowledge about different strategies to reduce STEC contamination in beef products without\nsignificantly affecting nor physicochemical characteristics neither sensory attributes Fil: Cap, Mariana. Universidad de Buenos Aires. Fecultad de Ciencias Veterinarias. Buenos Aires, Argentina Vaudagna, Sergio Leotta. Gerardo Cap, Mariana 2021-05-05 Escherichia coli productor de toxina Shiga (STEC) es un patógeno de transmisión\nalimentaria que causa diarrea sanguinolenta, colitis hemorrágica y síndrome urémico hemolítico. La carne contaminada con STEC impacta en el ámbito de la salud pública por el riesgo de enfermar al consumidor y en el ámbito económico por la pérdida que implica el rechazo de la carne contaminada con destino a la exportación. En este contexto, existe una fuerte demanda de evaluar la efectividad de los tratamientos antimicrobianos disponibles en el país frente a cepas nativas de STEC O157 y no O157.\nEl objetivo del presente trabajo fue evaluar, estandarizar y promover estrategias de intervención para reducir la presencia de STEC (O157 y no-O157) en cortes, recortes\n(materia prima para la preparación de hamburguesas) picada de carne bovina. Para ello,\nse realizaron 3 ensayos. En el ensayo 1 se evaluó la efectividad de ácido láctico (AL), ácido peroxiacético (AP), ácido caprílico (AC) y agua electroactivada (AE) para reducir STEC en cortes de carne vacuna. En el ensayo 2 se evaluó la efectividad de AL, AC e irradiación, solos y combinados, para reducir la presencia de STEC en recortes de carne\nbovina y, en el ensayo 3 se evaluó la efectividad de irradiación gamma para reducir STEC en carne bovina picada. En los 3 ensayos se evaluaron los efectos sobre los atributos sensoriales de las intervenciones más efectivas sobre las distintas matrices cárnicas evaluadas y, en los ensayos 1 y 2 también se evaluaron los efectos sobre los parámetros fisicoquímicos. El inóculo consistió en un coctel de cepas autóctonas de STEC pertenecientes a los serogrupos O26, O103, O111, O145 y O157. Las muestras se inocularon con dos concentraciones de bacterias, alta y baja. Las muestras con alta\nconcentración de STEC se analizaron por recuento en placa y las muestras con baja concentración de STEC se enriquecieron y se analizaron por PCR en tiempo real. La\nefectividad se evalúo en términos de número de reducciones logarítmicas para las muestras con IA y en términos de reducción del porcentaje de muestras positivas para los genes stx y eae en las muestras con IB. Los resultados del ensayo 1 evidenciaron que, de los 4 tratamientos analizados, sólo el AC fue efectivo con reducciones de 0,8 log UFC/g en las muestras con IA y del 77% en las muestras con IB. Los resultados del ensayo 2 evidenciaron que el tratamiento más efectivo fue el de irradiación con 2 kGy con reducciones de más de 5 log UFC/g en las muestras con IA y del 100 % en las muestras con IB. La combinación de AL e irradiación aumentó la letalidad en muestras\ncon IA pero no en muestras con IB. Los resultados del ensayo 3 de las muestras con IA evidenciaron que 1 kGy sería suficiente para reducir 5 log UFC/g en carne bovina picada.\nSin embargo, al exponer las muestras con IB a dicha dosis no se alcanzó la inactivación total. Con respecto a los efectos sobre los parámetros fisicoquímicos y los atributos sensoriales de los productos cárnicos se concluyó que las modificaciones fueron\nmínimas. Los resultados de este trabajo demuestran la importancia de evaluar la\nefectividad de los tratamientos antimicrobianos con más de un nivel de inóculo y constituyen un aporte de conocimiento para reducir la contaminación de STEC en carne bovina sin alterar de manera significativa los parámetros fisicoquímicos ni los atributos sensoriales de la misma. application/pdf STEC Carne bovina Irradiación gamma spa Universidad de Buenos Aires. Facultad de Ciencias Veterinarias info:eu-repo/semantics/openAccess htpps://creativecommons.org/licenses/by-nend/2.5/ar/ Carne vacuna Acidos orgánicos Escherichia coli Toxina Shiga Industria cárnica Radiación gamma Tecnología de los alimentos Doctora de Universidad de Buenos Aires en Ciencias Veterinarias Estrategias de intervención para mitigar el impacto de Escherichia coli productor de toxina Shiga en la cadena cárnica bovina info:eu-repo/semantics/doctoralThesis info:ar-repo/semantics/tesis doctoral info:eu-repo/semantics/acceptedVersion http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=avaposgra&cl=CL1&d=HWA_7021 https://repositoriouba.sisbi.uba.ar/gsdl/collect/avaposgra/index/assoc/HWA_7021.dir/7021.PDF |