Risk of biocontamination of salted environments by P. aeruginosa and E. coli.

Salty environments are susceptible to biological contamination by halotolerant microorganisms, by the phenotypic adaptation of microbial populations through the induction of survival mechanisms such as stress response pathways, and biofilm formation. Thus, this study aimed to investigate the bio-contamination risks posed by Pseudomonas aeruginosa and Escherichia coli in salted environments. The adhesion of the strains to glass and the surface energies were monitored in an aqueous medium at varying concentrations of sodium chloride (NaCl) (0%, 3%, 6%, 13%, 26%). Bacterial adhesion was observed by the optical microscopy, and the surface energies were estimated using the contact angle method. Surface energy measurements showed that NaCl was able to increase the electron donor (γ^-) and acceptor (γ⁺) characters, and the hydrophobicity (ΔG_iwi) of the bacterial surfaces at 3%. At 6%, 13%, and 26%, bacterial surfaces gradually regained their normal hydrophobicity. Similarly, the hydrophobicity of the glass surface increased and even reversed at 26%. The adhesion images showed an agglutination of the bacterial cells of both strains at 3% and 6%. However, at 6%, 13% and 26%, the adhesion becomes more dispersed and lighter. In brief, these findings suggest that NaCl may contribute to the enhancement of contamination in salted environments. Consequently, this raises concerns regarding the potential for bio-contamination in salty foods.