Listeria monocytogenes en quesos artesanales expendidos en cuatro mercados de Trujillo - Perú, 2023
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Date
2023
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Publisher
Universidad Nacional de Trujillo
Abstract
Listeria monocytogenes es una bacteria que puede causar listeriosis en las personas cuando se ingieren alimentos crudos o procesados dentro de los que están los productos lácteos fermentados como los quesos por lo que se determinó la frecuencia de L. monocytogenes en quesos artesanales expendidos en cuatro mercados de la provincia de Trujillo entre junio y octubre del 2023. Se evaluaron 200 quesos artesanales adquiridos en los mercados Zonal Palermo, La Hermelinda, ASCOMALAC y Central. De cada muestra de queso se pesó 25g. y colocó en caldo de enriquecimiento para Listeria tamponado y suplementado, e incubó a 32°C durante 24 horas; luego se sembró en Agar Oxford e incubó a 37°C por 48 horas. Se aislaron colonias de color marrón grisáceo a negro con halo negro y bordes enteros; la identificación fenotípica se realizó mediante las pruebas de catalasa, motilidad, hemólisis y fermentación de carbohidratos. Se consideraron cultivos positivos a L. monocytogenes aquellos cultivos que resultaron ser catalasa, motilidad, beta hemólisis y ramnosa positivos; y manitol y xilosa negativos. Se evidenció el 1.5% (3/200) de quesos artesanales con L. monocytogenes, por lo que su consumo constituye un potencial riesgo para la salud humana.
Listeria monocytogenes is a bacteria that can cause listeriosis in people when raw or processed foods are ingested, including fermented dairy products such as cheeses, so the frequency of L. monocytogenes in artisanal cheeses sold in four markets was determined. the province of Trujillo between June and October 2023. 200 artisanal cheeses acquired in the Zonal Palermo, La Hermelinda, ASCOMALAC and Central markets were evaluated. 25g of each cheese sample was weighed. and placed in buffered and supplemented Listeria enrichment broth, and incubated at 32°C for 24 hours; then it was sown on Oxford Agar and incubated at 37°C for 48 hours. Grayish brown to black colonies with black halo and entire edges were isolated; Phenotypic identification was carried out through catalase, motility, hemolysis and carbohydrate fermentation tests. Cultures that were catalase, motility, beta hemolysis, and rhamnose positive were considered positive for L. monocytogenes; and mannitol and xylose negative. 1.5% (3/200) of artisanal cheeses were found to contain L. monocytogenes, so its consumption constitutes a potential risk to human health.
Listeria monocytogenes is a bacteria that can cause listeriosis in people when raw or processed foods are ingested, including fermented dairy products such as cheeses, so the frequency of L. monocytogenes in artisanal cheeses sold in four markets was determined. the province of Trujillo between June and October 2023. 200 artisanal cheeses acquired in the Zonal Palermo, La Hermelinda, ASCOMALAC and Central markets were evaluated. 25g of each cheese sample was weighed. and placed in buffered and supplemented Listeria enrichment broth, and incubated at 32°C for 24 hours; then it was sown on Oxford Agar and incubated at 37°C for 48 hours. Grayish brown to black colonies with black halo and entire edges were isolated; Phenotypic identification was carried out through catalase, motility, hemolysis and carbohydrate fermentation tests. Cultures that were catalase, motility, beta hemolysis, and rhamnose positive were considered positive for L. monocytogenes; and mannitol and xylose negative. 1.5% (3/200) of artisanal cheeses were found to contain L. monocytogenes, so its consumption constitutes a potential risk to human health.
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Keywords
Listeria monocytogenes, Mercados de abasto