The use of vortex and ultrasound techniques for the in vitro removal of Salmonella spp. Biofilms
Webber, BrunaCanova, RaíssaEsper, Luciana MariaPerdoncini, GustavoNascimento, Vladimir Pinheiro doPilotto, FernandoSantos, Luciana Ruschel dosRodrigues, Laura Beatriz
Background: The presence of biofilm is common to all types of surfaces, such as stainless steel. Once formed, biofilms act as a point of constant contamination releasing fragments or planktonic cells of microorganisms, such as Salmonella spp., and may impair the microbiological quality of products. The laboratory methods are being used and tested in vitro for removal and the subsequent quantification of biofilms, including the use of vortex and ultrasound. The aim of the study was to evaluate the effectiveness of these two laboratory methods for removing Salmonella spp. biofilms, in vitro cultured on stainless steel surface from the food industry.Materials, Methods & Results: Three strains were analyzed for biofilm formation by Salmonella spp., and they are S. Typhimurium ATCC 14028, S. Enteritidis ATCC 13076 and S. Enteritidis isolated from drag swab on poultry farm and genetically confirmed by Microarray, denominated P106. Coupons of stainless steel AISI 316, with an area of 1 cm² were used. These materials used for the coupons were obtained from the equipments at the cutting room in the poultry slaughterhouse. Biofilms were formed using TSB broth without glucose and incubated at 36°C for 24 h. Six replicates were performed for each microorganism in each removal method. After the biofilm formation, two methods were used in the removal stage, the vortexing, performed for 2 min, and the sonication method, with coupons maintained for 10 min in an ultrasound bath, at a frequency of 40 kHz and potency 81 W. Serial dilutions were made and transferred to PCA agar for quantification in log10CFU.mL-1. The microtopography was performed by scanning electron microscopy (SEM) of surfaces before the removal step. Statistical analysis of the results showed no significant difference between the two removal methods and between the three strains studied (P > 0.05).[...](AU)
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