Lactic Acid Bacteria as the Green and Safe Food Preservatives: Their Mechanisms, Applications and Prospects

Microbial contamination of food is a crucial cause of food spoilage and foodborne diseases, posing a severe threat to global public health. Although chemical preservatives are effective, their potential hazards to human health and the environment, coupled with the growing demand for "clean label" products, have driven the search for natural alternatives. Lactic acid bacteria (LAB), recognized as the Generally Recognized as Safe (GRAS) microorganisms, have emerged as the promising bio-preservatives due to their safety, effectiveness, and multifunctionality. This review systematically summarized the core antimicrobial properties of LAB, including their inhibitory spectrum against foodborne pathogens, spoilage microorganisms, viruses, parasites, and their ability to degrade toxic substances such as mycotoxins, pesticides, and heavy metals. Key inhibitory mechanisms of LAB are highlighted, encompassing the production of antimicrobial metabolites, leading to metabolism disruption and cell membrane damage, nutrition and niche competition, quorum-sensing interference, and anti-biofilm formation. Furthermore, recent advances in LAB applications in preserving various food matrices (meat, dairy products, fruits and vegetables, cereals) are integrated, including their roles in enhancing food sensory quality, extending shelf life, and retaining nutritional value. The review also discusses critical factors influencing LAB's inhibitory activity (medium composition, culture conditions, ionic components, pathway regulator, etc.) and the challenges associated with the application of LAB. Finally, future research directions are outlined, including the novel LAB and metabolites exploration, AI-driven cultural condition optimization, genetic engineering application, nano-encapsulation and active packaging development, and building up the LAB-based cellular factories. In conclusion, LAB and their antimicrobial metabolites hold great promise as green and safe food preservatives. This review is to provide comprehensive theoretical support for the rational improvement and efficient application of LAB-based natural food preservatives, contributing to the development of a safer and more sustainable food processing and preservation systems.