Modelling of Listeria monocytogenes growth and survival in presence of royal jelly, a promising anti-biofilm agent

Abstract

Royal jelly is a natural bee product with well-known antimicrobial properties and prominent clinical uses. The main objective of this study was to reveal the response of L. monocytogenes to royal jelly. Firstly, the influence of royal jelly on the growth kinetic parameters of L. monocytogenes ATCC 7644 was studied with the modified Gompertz mathematical equation. Results indicated that royal jelly retarded the growth of L. monocytogenes by acting mainly on the lag phase duration. Microdilution assay on L. monocytogenes ATCC 7644 performed with two-fold serial dilution method showed that minimal inhibitory concentration (MIC) was 41.67 mg.ml(-1). However, the estimated MIC value modelled with Gompertz survival curve (23.85 mg.ml(-1)) and the validated value (24 mg.ml(-1)) were notably lower than in the micro-dilution assay. It is noteworthy that the predictive microbiology approach has good performance in determining the optimum dose and cost-effective of antimicrobial agents. To our knowledge, biofilm prevention by royal jelly has not yet been studied and a limited number of studies regarded the effects on Listeria monocytogenes. The ability to reduce the formation of biofilm with royal jelly may allow further studies to explore the use of apiculture products in the struggle with L. monocytogenes.