Adaptação e adaptação cruzada de biofilmes de Salmonella sp. a linalol, citral e cinamaldeído

Abstract

Salmonellosis is a toxinfection that may be acquired by food contaminated with Salmonella, and its pathogeny is marked by the occurrence of severe symptoms and possibe death. Biofilms are bacterial cell aggregates, which produce polymeric substances that form communication networks. The capacity Salmonella has of forming biofilm influences the high number of food poisoning outbreaks given that it raises the resistance and persistence on colonized surfaces. Essential oils and major compounds are considered an efficient alternative as common chemical sanitizers in food industry by reaching several targets on the microbial cell. However, bacteria may consume sublethal concentrations of major compounds causing them to become inactive. Thus, this work aimed at verifying the bactericidal effect of planktonic and sessile cells of Enteritidis and Typhimurium Salmonella enterica serotypes under sublethal stress conditions, and at evaluating the consumption kinetics of cinnamaldehyde by the same serovars using HPLC. The lowest concentrations capable of eliminating planktonic cells of Salmonella serovars were under the effect of cinnamaldehyde and biofilms and suffered inhibition with doses of citral. Adaptation in the planktonic stage rose biofilm resistance whereas the sublethal exposure during the sessile stage reduced MBBC. Cross-adaptation tests showed that cinnamaldehyde is efficient after sublethal exposure of other major compounds, and sublethal doses of linalol affected the resistance mechanisms of Citral, causing them to become ineffective. The kinetics of cinnamaldehyde consumption by Salmonella serovars depends on the concentration of exposure. After 8 hours of incubation, sublethal doses were almost depleted and the mean of obtained area showed statistical difference for both serovars (p < 0.05%). In lethal doses, a significant conservation of initial doses of cinnamaldehyde was observed, and the mean of the areas showed no difference (p < 0.05%). This study highlights the high adaptive resistance capacity of S. Enteritidis and S. Typhimurium biofilms on common surfaces of the food industry, as well as the effectiveness of major compounds of essential oils over microbiological control, since their safety for use.