This thesis is an investigation of the potential of Allyl Isothiocyanate (AITC) derived from oriental mustard meal (Brassica juncea meal) as a natural preservative suppression moulds growth on bread. Currently, clean labels and natural antimicrobial agents are interests of alternative preservatives. In this study, an antimicrobial sachet/patch containing B. juncea meal was developed to produce AITC vapour in situ; the efficacy of gaseous AITC/B. juncea meal on suppression of Penicillium spp. and other mould growth was investigated. The growth was completely inhibited for 28 days at 23˚C in the presence of 0.7-1.3 ppm AITC in the headspace (released from 50-100 mg B. juncea meal). Fifty mg mustard meal showed fungistatic activity, and ≥100 mg were fungicidal. The shelf life of sliced white bread (600 g) was prolonged for 14 days using 3g of B. juncea meal at 23˚C thereby illustrating the potential of AITC as an alternative to chemical preservatives.