Antimicrobial Activity of Nanoclay Films Enriched with Citrus aurantium Essential Oil against Indicator FoodBorne Pathogens in Fishery Products

In recent years, edible films and coatings that are nutritious and able to significantly control microbial loads for the food safety have been further popular. In this study, effects of nanoclay film of citrus essential oil on bacterial pathogens of Listeria monocytogenes, Vibrio parahaemolyticus, Streptococcus iniae and Salmonella typhi were investigated in fishery products, including silver carp surimi, grass carp sausages and common carp tofu.

The nanoclay film was prepared using solution of sodium alginate and solid sodium gelatin. The film solution was mixed with 0.2, 0.4 and 0.6% of citrus essential oil. Bacterial load in fish products was investigated on Days 0, 7 and 14.

The microbial load significantly increased by 0.2, 0.4 and 0.6% (p < 0.05) in nanoclay treatment of the citrus essential oil in silver surimi, grass carp sausage and common carp tofu from Day 0 to Day 14. Load of bacteria in fishery products included 0.4 and 0.6% in nanoclay treated with citrus essential oil until Day 14, compared to controls. The exceptions included common carp tofu contaminated with Salmonella typhi and Streptococcus iniae and grass carp sausages contaminated with Streptococcus iniae treated with 0.6% citrus essential oil contained nanoclay; in which, the bacterial load increased up to Day 14.

Results showed that nanoclay with 0.4 and 0.6% of citrus essential oil was able to control the microbial load in fisheries products. This activity depended on the bacterial species as well as percentage of the citrus essential oil.