Antibacterial Activities of Sophorolipids and Nisin and Their Combination against Foodborne Pathogen Staphylococcus aureus

Abstract

In food processing, both preservatives and surfactants are usually added to ensure the quality of food. Sophorolipids (SLs) are extracellular biosurfactants produced by yeasts that have antibacterial activities. Nisin is a polycyclic antibacterial peptide produced by Lactococcus lactis. In this study, the possibility of using SLs alone as a preservative and in combination with nisin as a compound additive is investigated. SLs and nisin exhibit effective antibacterial activities against foodborne pathogen Staphylococcus aureus with minimum inhibitory concentrations of 32 and 0.5 µg mL−1, respectively. Both SLs and nisin increase cell wall and cell membrane permeability of S. aureus, enhance intracellular content release and activities of extracellular ALP and β‐galactosidase, and reduce respiratory‐chain dehydrogenase activity of the pathogen. Fractional inhibitory concentration (FIC) index for SLs and nisin combination is 1.5, indicating the effect of SLs with nisin is additive. Results of the study indicate that SLs could be used alone as a preservative or in combination with nisin as a promising compound additive with functions of both emulsifier and preservative. Practical Applications: SLs could be used alone as a preservative in food industry or in combination with nisin as a promising compound additive with functions of both emulsifier and preservative.

Sophorolipids—Bio-Based Antimicrobial Formulating Agents for Applications in Food and Health

“…Production of sophorolipids from marine yeast Rhodotorula rubra has been observed to show antibacterial activities against foodborne pathogens E. coli and S. aureus with the utilization of Macrocystis pyrifera extract as a nutrient source [ 68 ]. Similar antibacterial potentials were demonstrated by Chen et al when they combined nisin with sophorolipids to form antimicrobial food preservatives [ 69 ]. Based on Gaur et al [ 70 ], sophorolipids from Candida albicans and Candida glabrata have been shown to be effective antibacterial biomolecules against both Gram-positive and Gram-negative bacterial pathogens through the formation of reactive oxygen species (ROS) [ 70 ].…”

The antibacterial mechanism of perilla rosmarinic acid

“…Naturally produced fatty acid monoglycerides have bacteriostasis to S. aureus , B. subtilis , Pseudomonas aeruginosa , and E. coli 16 . Chen et al 17 . found that the combined application of sophora lipids and streptococcus has a strong bacteriostasis on food‐borne S. aureus .…”

Antibiotic Susceptibility of Staphylococcus Species Isolated in Raw Chicken Meat from Retail Stores

“…Staphylococcal food contamination represents the greatest economically significant foodborne illness [ 28 ] and produces gastrointestinal illness through a wide variety of toxins [ 29 ], including staphylococcal enterotoxins characterized by vomiting and diarrhea within 2 to 6 h after the consumption of contaminated food [ 30 , 31 , 32 ]. A large number of daily consumed foods serve as an optimum growth medium for S. aureus [ 27 ], and this varies from country to country, especially due to different habits in food consumption [ 33 ].…”