Abstract

The perception of Minimally processed (MP) salad vegetables as healthy and convenient has led to an increasing popularity for such foods. Concerns regarding the microbiological safety of minimally processed salad vegetables arise as their unique characteristics enhances the growth of microorganisms, including those which can grow at refrigeration temperatures. For food processors the challenge is to produce a safe product with extended shelf-life. Normal catering operations require well defined instructions for the safe handling and preparation of salad vegetables which exist for other food groups such as meat, dairy and fish products. This research project was devised to examine the microbiological consequences of using NaDCC (sodium dichlorisocyanurate), commercially available as Aquatabs, as a surface disinfectant during the preparation of salad vegetables in catering or processing operations. Experiments were designed to do the following: 1. To reduce the microbial load on the surface of cut butterhead lettuce during it’s preparation using NaDCC as a chlorine dip. 2. To examine the antimicrobial effect of NaDCC on the different physiological groups of microorganisms present on cut lettuce and cabbage. 3. To examine the effect of NaDCC on foodbome pathogens commonly associated with vegetables in-vivo. 4. To compare Aquatabs to another commercially available chlorine product and two organic acid products as surface disinfectants for cut lettuce. Results showed that treatment of cut lettuce with NaDCC (Aquatabs) significantly improved the microbiological quality. When applying the disinfectant to salad vegetables intended for refrigerated storage, the pH of the chlorine solution, drying post treatment and type of vegetable are important factors to be considered. Treatment of cut lettuce with NaDCC also significantly reduced pathogens in-vivo contributing to the microbiological safety of the product. The efficiency of NaDCC disinfectants was similar to the lactic acid disinfectants. The survival of microorganisms was attributed to the surface microenvironment of the salad vegetable which protected the microoganisms from the biocidal action of the disinfectants.