The identification of critical lethal action in antimicrobial mechanism of glycerol monomyristate against foodborne pathogens

Abstract

22Glycerol monomyristate (GMM) is a promising antimicrobial substance due to its broad 23 antibacterial spectrum: however, the critical lethal action in its antimicrobial mechanism 24 for foodborne pathogens remains unclear. In the present study, the inhibitory activities of 25 GMM on Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Candida 26 albicans (C. albicans) were compared, and its membrane and intracellular action 27 mechanism was investigated. The results showed that the susceptibility of E. coli to 28 GMM was the highest, followed by S. aureus, and C. albicans being the poorest. Using 29 flow cytometry, the GMM dose causing above 50% permeability ratio on E. coli was 30 lower than that on S. aureus. The images from scanning electron microscope revealed no 31 doses difference existed between the two strains when the obvious cell damage occurred. 32Furthermore, cell cycle and multiple fluorescent staining assays showed only the cell 33 division of E. coli and S. aureus, excluding that of C. albicans, was obviously affected at Importance 38 Foodborne pathogens, as a common source of biological pollution in the food industry, 39 can cause millions of food poisoning incidents each year, which poses great risks to 40 consumers' health and safety. The use of monoglyceride as an edible surfactant to inhibit 41 the growth of food-borne microorganisms has been a long time, but the relevant 42 3 antibacterial mechanism is too broad to accurately grasp its key lethal effect and its 43 action doses, which not only affects the antibacterial efficiency, but also may result in the 44 abnormalities of food flavor when adding at overdoses. The significance of the study is 45 to identify the key lethal effect and its action doses, which will greatly enhance the 46 understanding of the response mechanism of different types of foodborne pathogens to 47 monoglycerides, and provide a more reasonable reference for differential control and 48 treatment of different gastrointestinal infections when combined with antibiotics in 49 clinical. 50 51 52 53 54 55 56 57 58 59 60 61 62 63 4 Introduction 64Food safety is very important to global public health. The control of foodborne 65 pathogens has always been the major task in the food industry. There are millions of 66 gastrointestinal infection cases every year due to consuming foods contaminated with 67 harmful microbes (1). Owing to the concern of the potential toxicity of chemical 68 preservatives (2), researchers have been striving to find effective and safe substances to 69 replace traditional chemical preservatives such as benzoate, sorbate, and propionate (3). 70Monoglycerides are important non-ionic surfactants with broad antibacterial spectrum, 71 strong antibacterial activity, and high stability (4). Among them, glycerol monomyristate 72 (GMM) show both excellent bacterial and fungal inhibitory ability (5, 6). For example, 73 myristic acid and its monoglyceride showed a moderate inhibition effect on the growth of 74 Aspergillus, Penicillium, and Fus...