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This work aimed to develop an edible antimicrobial coating based on a starch-chitosan matrix to evaluate its effect on minimally processed carrot by means of microbiological analyses. Coatings based on 4% yam starch (w/w) + 2% glycerol (w/w) and coatings based on 4% yam starch (w/w) + 2% glycerol (w/w) + chitosan in 0.5% and 1.5% concentrations were prepared. Samples of minimally processed carrot slices were immersed into these coatings. All the samples were placed in expanded polystyrene trays, wrapped in polyvinylchloride film and stored at 10°C/15 days. During storage, all the samples had counting <100 CFU/g for Staphylococcus aureus and <3 MPN/g for Escherichia coli. Starch + 0.5% chitosan coating controlled the growth of mesophilic aerobes, yeasts and molds and psychrotrophs during the first five days of storage, ultimately presenting reductions of only 0.64, 0.11 and 0.16 log cycles, respectively, compared to the control. Starch + 1.5% chitosan coated samples showed reductions in mesophilic aerobes, mold and yeast and psychrotrophic counting of 1.34, 2.50 and 1.30 log cycles, respectively, compared to the control. The presence of 1.5% chitosan in the coatings inhibited the growth of total coliforms and lactic acid bacteria throughout the storage period. The use of edible antimicrobial yam starch and chitosan coating is a viable alternative for controlling microbiological growth in minimally processed carrot.

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Consumers are increasingly demanding foods with lower synthetic preservatives. Plant essential oils are natural compounds with remarkable antimicrobial properties and may be incorporated as emulsions into water-soluble polymers to form antimicrobial films. Coarse emulsions (diameters of 1.3-1.9 μm) and nanoemulsions (diameters of 180-250 nm) of clove bud (Syzygium aromaticum) and oregano (Origanum vulgare) essential oils were produced through low-speed mixing and ultrasonication, respectively. Methylcellulose was added for film-forming purposes. Both essential oils reduced the rigidity and increased the extensibility of the methylcellulose films, effects that were even more pronounced for nanodroplets. Both essential oils lessened the counts of yeasts and molds in sliced bread during 15 days, and droplet size reduction provided a further improvement in antimicrobial properties. Due to increased bioavailability, less preservative content might be used and still deliver the same antimicrobial efficiency if encapsulated in smaller particles.

a b s t r a c tAntimicrobial packaging, besides protecting the product from external environment, inhibits or retards microorganism growth in foods, minimizing direct addition of preservatives and satisfying the actual demand of consumers for healthier foods, containing less additives. Pediocins are antimicrobial peptides produced by Pediococcus sp. and researches have revealed their ability to inhibit the growth of some pathogenic bacteria. The objective of this work was to develop and evaluate the antimicrobial efficiency of films incorporated with pediocin on sliced ham conservation. The antimicrobial films were incorporated with pediocin (25% and 50%) in a cellulose base emulsion. The antimicrobial efficiency of the films against Listeria innocua e Salmonella sp. on sliced ham was tested by means of a challenge test, in which the slices were immersed in 0.1% peptone solution containing about 10 6 CFU/mL of L. innocua or Salmonella sp. The experiment was set up overlapping the slices of ham with the films (control, 25% and 50% of pediocin). These systems were packaged under vacuum and stored at 12°C. The slices of ham were analyzed for L. innocua and Salmonella sp. counts at 0, 3, 6, 9, 12 and 15 storage days. The antimicrobial films were more effective inhibiting growth of L. innocua. The 50% pediocin-film presented a reduction of 2 log cycles in relation to control treatment after 15 days of storage. The 25% and 50% pediocin-films had similar performance on Salmonella sp. inhibition, both presenting 0.5 log cycle reduction in relation to control, after 12 days of storage. Hence, the films incorporated with pediocin showed potential use as one hurdle technology added in the storage period among others good manufacturing practices for preservation of sliced ham.