Susceptibility of Vegetative Cells and Endospores of Bacillus cereus to Rhamnolipid Biosurfactants and Their Potential Application in Dairy

Author(s)

Bertuso, Paula de Camargo ; Marangon, Crisiane Aparecida ; Nitschke, Marcia

• Document type: Journal article
• Source: MICROORGANISMS; v. 10, n. 9, p. 17-pg., 2022-09-01.

Abstract

Bacillus cereus is a Gram-positive, endospore-forming bacterium well-known as a food pathogen that causes great losses in the food industry, especially in dairy. In this study, rhamnolipid (RL) biosurfactants were evaluated as a bio-based alternative for controlling the growth of vegetative cells and endospores of B. cereus. RLs were tested against 14 B. cereus strains isolated from different types of foodstuffs. The antimicrobial activity against vegetative cells and endospores revealed minimal inhibitory concentration (MIC) values of 0.098 mg/mL for almost all strains tested and minimal bactericidal concentration (MBC) varying between 0.098 and >25 mg/mL. The presence of RLs inhibited endospore germination by more than 99%, reducing by 5.5 log the outgrowth of strain 0426. Scanning and transmission electron microscopy confirmed that exposure to RL causes damage to the structure of endospores. When skim milk was utilized as a food model, RL inhibited the growth of vegetative cells and endospores of B. cereus, showing MBC of 3.13 mg/mL for the vegetative cells of strain 0426. The surfactant also reduced bacterial growth in milk at refrigerator temperature. The results suggest that RLs are promising candidates for the development of novel strategies to control B. cereus in the food industry. (AU)

• FAPESP's process: 19/14405-9 - Exploring the potential of Rhamnolipid on controlling food pathogens: effect of ionic strength and biopolymers
• Grantee: Marcia Nitschke
• Support Opportunities: Regular Research Grants
• FAPESP's process: 19/22799-7 - Exploring the potential of biopolymers with fruit extracts nanoparticles on controlling food pathogens
• Grantee: Crisiane Aparecida Marangon
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 21/09935-9 - Innovative approaches in the use of rhamnolipids in food: control of endospores and interaction with sucrose
• Grantee: Marcia Nitschke
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/22214-6 - Towards a convergence of technologies: from sensing and biosensing to information visualization and machine learning for data analysis in clinical diagnosis
• Grantee: Osvaldo Novais de Oliveira Junior
• Support Opportunities: Research Projects - Thematic Grants