Nisin is a bacteriocin synthesized by certain species of Lactococcus lactis, that has been recently employed as a preservative in the food industry. Taking into account its potential as a natural preservative, its applicability in cosmetics and topical products was probed, aiming to replace or reduce the use of synthetic preservatives currently used in these products. In vitro susceptibility tests were performed using the plate diffusion method and the "Challenge Test". The action of nisin was tested when applied alone and in synergy with ethylenediaminetetraacetic acid tetrasodium salt (EDTA) and similar synthetic preservatives, Abiol® (INCI-Imidazolidinyl urea) and Microcare PM2 (Phenoxyethanol, Ethylparaben, Methylparaben). The results of this study demonstrate that nisin is effective in inhibiting gram-positive microorganisms Staphylococcus aureus and Bacillus sp. However, for other tested microorganisms, only the combination of nisin, EDTA and synthetic preservatives, respectively at 125 ppm/0.1/0.35%, showed antimicrobial activity in compliance with criterion A from ISO 11930. With this study, it is concluded that nisin can be a viable alternative when associated with other preservatives, reducing the use of higher doses of chemical/synthetic preservatives that are often associated with sensitivity and allergic reactions.
- Antimicrobial tests