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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Listeria monocytogenes Serotype 1/2b and 4b Isolates from Human Clinical Cases and Foods Show Differences in Tolerance to Refrigeration and Salt Stress

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Autor(es):
Ribeiro, V. B. [1] ; Destro, M. T. [1]
Número total de Autores: 2
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Dept Food & Expt Nutr, BR-05508000 Sao Paulo - Brazil
Número total de Afiliações: 1
Tipo de documento: Artigo Científico
Fonte: JOURNAL OF FOOD PROTECTION; v. 77, n. 9, p. 1519-1526, SEP 2014.
Citações Web of Science: 8
Resumo

Control of Listeria monocytogenes in food processing facilities is a difficult issue because of the ability of this microorganism to form biofilms and adapt to adverse environmental conditions. Survival at high concentrations of sodium chloride and growth at refrigeration temperatures are two other important characteristics of L. monocytogenes isolates. The aim of this study was to compare the growth characteristics under stress conditions at different temperatures of L. monocytogenes serotypes responsible for the majority of clinical cases from different sources. Twenty-two L. monocytogenes isolates, 12 from clinical cases (8 serotype 4b and 4 serotype 1/2a) and 10 from food (6 serotype 4b and 4 serotype 1/2a), and an L. monocytogenes Scott A (serotype 4b) reference strain were analyzed for the ability to grow in brain heart infusion broth plus 1.9 M NaCl (11%) at 4, 10, and 25 degrees C for 73, 42, and 15 days, respectively. The majority of L. monocytogenes strains was viable or even grew at 4 degrees C and under the high osmotic conditions usually used to control pathogens in the food industry. At 10 degrees C, most strains could adapt and grow; however, no significant difference (P > 0.05) was found for lag-phase duration, maximum growth rate, and maximum cell density. At 25 degrees C, all strains were able to grow, and populations increased by up 5 log CFU/ml. Clinical strains had a significantly longer lag phase and lower maximum cell density (P < 0.05) than did food strains. Regarding virulence potential, no significant differences in hemolytic activity were found among serotypes; however, serotype 4b strains were more invasive in Caco-2 cells than were serotype 1/2a strains (P < 0.05). The global tendency of decreasing NaCl concentrations in processed foods for health reasons may facilitate L. monocytogenes survival and growth in these products. Therefore, food companies must consider additional microbial growth barriers to assure product safety. (AU)

Processo FAPESP: 09/14618-0 - Expressão de genes de virulência em cepas de Listeria monocytogenes isoladas de casos clínicos e de alimentos, submetidas a diferentes condições de crescimento
Beneficiário:Vinicius Buccelli Ribeiro
Linha de fomento: Bolsas no Brasil - Doutorado
Processo FAPESP: 09/16931-8 - Expressão de genes de virulência em cepas de Listeria monocytogenes isoladas de casos clínicos e de alimentos, submetidas a diferentes condições de crescimento
Beneficiário:Maria Teresa Destro
Linha de fomento: Auxílio à Pesquisa - Regular