Natural technologies to control saprophytic and pathogenic microorganisms in fresh vegetables

PONCE, ALEJANDRA, G., MOREIRA, MARÍA DEL R, DEL VALLE, CARLOS, E. AND ROURA, SARA, I

Research Advances in Food Science

Global Research Network

Lugar: Kerala (India).; Año: 2005; p. 21 - 26

The exploration of naturally occurring antimicrobials for food preservation receives increasing attention due to consumer awareness of natural food products and a growing concern of microbial resistance towards conventional preservatives. Many spices and herbs exert antimicrobial activity to their essential oil fractions, also some native microflora naturally present on fresh produce surfaces are capable of producing antimicrobial compounds playing an important role maintaining fresh vegetable quality and safety. The use of essential oils on fresh vegetables, as an alternative to the use of synthetic chemicals to preserve organically grown produce, was investigated through in vitro and in vivo experiments. Some oils presented antimicrobial and antioxidant activities that indicate clearly their potential to become technological useful products as sanitizing agents. Clove and tea tree essential oils were highly inhibitory to a selected pathogen (E. coli). The potential use of microbial growth inhibitors derived from lactic acid bacteria occurring naturally in organically produced leafy vegetables was investigated. Four lactic acid bacteria strains presented antagonistic activity against indicator microorganisms, food borne pathogens or taxonomically similar microorganisms from the same raw material. These strains were identified as L. lactis, E.  faecium, E. hirae and E. canis.  Metabolic end products from E. faecium and E. canis cultures presented the capacity to inhibit the growth of Gram negative and Gram positive food-borne pathogens such as E. coli and L. monocytogenes.