| Congresso Brasileiro de Microbiologia 2023 | Resumo: 777-2 | ||||
Resumo:This study focused on evaluating the inhibitory effect of lactic acid (LA) + acetic acid (AA) on the formation of multispecies biofilms, which included Listeria monocytogenes (Listeriaceae), Salmonella spp. (Enterobacteriaceae), and accompanying microbiota (Streptocococaceae, Pseudomonadaceae, Moraxelaceae, Yersiniaceae, and Enterobacteriaceae), isolated from surfaces of equipment and utensils in animal origin food industries. A total of 480 samples were collected from poultry, pork, and dairy product processing facilities, which were regularly inspected by the Federal Inspection Service in Brazil. Biofilms were formed on polypropylene surfaces and treated with 0.12 mg/mL LA + 0.12 mg/mL AA at 10°C for different time intervals (3, 24, 120, 216, and 312 hours). Viable cell counts, bacterial ecology, and architecture were assessed at each time point to understand the impact of the treatment on biofilm development. The results indicated that the bacterial consortium successfully formed multispecies biofilms on the polypropylene surface, with the highest counts observed at 312 hours. However, when treated with LA+AA, significant reductions in viable cell counts were observed, ranging from 39.34% to 99.993%, with the lowest counts at 24, 120, 216, and 312 hours. The bacterial diversity in the biofilms was evaluated using 16S rRNA gene sequencing, and the relative frequency of microorganisms was analyzed up to the family level. Notably, the treatment with LA+AA resulted in changes in the relative frequency of certain bacterial families. For instance, Yersiniaceae family had reduced relative frequency in the LA+AA-treated biofilm, mainly at 120, 216, and 312 hours. Streptococcaceae, on the other hand, was more frequent in the biofilm treated with LA+AA, regardless of the evaluation time. Additionally, Enterobacteriaceae were present in the early stages of biofilm formation in both the control and LA+AA-treated biofilms. The Moraxellaceae family was detected in the control biofilm but not in the LA+AA-treated biofilm, while Pseudomonadaceae showed higher relative frequency in the LA+AA-treated biofilm and was not detected in the control. A significant difference in alpha (p=0.003) and beta (p=0.001) diversity was observed in the different biofilms studied. Furthermore, the architecture of the biofilms was analyzed using scanning electron microscopy (SEM). The biofilms formed with LA+AA showed a lower number of bacterial cells and lacked the deposition of exopolysaccharide matrix (EPS). Overall, the study suggests that the use of LA+AA as a treatment can effectively reduce viable cell counts, alter the relative frequency and diversity of bacterial species, and modify the architecture of multispecies biofilms. These findings are relevant in the context of food safety and public health, as LA+AA treatment could be considered as an effective adjunct in the sanitization process of industrial surfaces to control the formation and persistence of biofilms. Palavras-chave: antibiofilm, control methods, microbial ecology, 16S rRNA, Agência de fomento:Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Process nº 2020/01529-9, 2022/03062-6 and 2023/01195-1. | |||||