Dados do Trabalho

Título

EVALUATION OF BACTERIAL BIOFILM FORMATION ISOLATED FROM INDUSTRIALIZED AND BULK FUNCTIONAL FLOURS

Introdução

In Brazil, the diversity of fruits and vegetables processed into functional flours offers numerous nutritional and therapeutic properties, aiding in the management of metabolic diseases such as diabetes, obesity, cardiovascular complications, and hypertension. Compliance with microbiological standards is essential for these flours, but bacteria like Salmonella spp., Escherichia coli, and Bacillus cereus, which are critical criteria for microbiological evaluation, have the ability to form biofilms on abiotic surfaces used in the production, storage, and distribution chain of these products. This study aimed to evaluate the biofilm formation by bacteria isolated from industrialized and bulk-sold functional flours.

Material e Métodos

Twenty-five strains isolated from 19 flour samples (10 industrialized and nine bulk) were identified using Matrix-Assisted Laser Desorption Ionization – Time of Flight/Mass Spectrometry (MALDI-TOF/MS) and VITEK® 2. The strains were cultured in brain-heart infusion (BHI) broth and incubated at 22.5°C and 37°C to simulate environmental conditions in stores and temperatures favorable for microorganisms, respectively. Biofilm quantification was performed using the crystal violet staining technique on polystyrene microplates, measuring optical density at 600 nm with a spectrophotometer.

Resultados e Discussão

Biofilm formation varied according to the bacterial strain and temperature. Klebsiella pneumoniae represented 12% of the strains (n=3) and showed a high capacity for biofilm formation, with 44% of the strains being moderately adherent at 22.5°C and strongly adherent at 37°C. In contrast, E. coli (4% of the total) displayed greater biofilm formation at 22.5°C compared to 37°C. Strains of Bacillus cereus (44%) and Cronobacter spp. (40%) formed weakly adherent biofilms regardless of the temperature. Notably, the strains with the highest biofilm formation capacity originated from bulk flour samples (three K. pneumoniae strains). Biofilm formation in flours is influenced by both temperature and bacterial strain. The presence of nutrients, combined with deficiencies in hygienic-sanitary procedures in storage locations, creates an environment conducive to biofilm formation, which once established, enhances resistance to disinfectants. Therefore, it is essential to assess microbiological risks and outline effective disinfection strategies that ensure food safety and quality.