ABSTRACT
[This corrects the article DOI: 10.1371/journal.pone.0201812.].
ABSTRACT
ABSTRACT The objective of this study was to evaluate the antifungal activity of nanoemulsions encapsulating essential oil of oregano (Origanum vulgare), both in vitro and after application on Minas Padrão cheese. Nanodispersions were obtained by the phase inversion temperature method. Cladosporium sp., Fusarium sp., and Penicillium sp. genera were isolated from cheese samples and used to evaluate antifungal activity. Minimal inhibitory concentrations of non-encapsulated and encapsulated oregano essential oil were determined, and they were influenced by the encapsulation of the essential oil depending on the type of fungus. The antifungal activity of the nanoencapsulated oregano essential oil in cheese slices showed no evidence of an effect of the MICs, when applied in the matrix. On the other hand, an influence of contact time of the nanoemulsion with the cheese was observed, due to the increase in water activity. It was concluded that nanoencapsulated oregano essential oil presented an inhibitory effect against the three genera of fungi evaluated. If environmental parameters, such as storage temperature and water activity, were controlled, the inhibitory effect of nanoemulsions of oregano oil could possibly be greatly improved, and they could be presented as a potential alternative for the preservation of Minas Padrão cheese against fungal contamination.
Subject(s)
Oils, Volatile/pharmacology , Cheese/microbiology , Origanum/chemistry , Food Preservation/methods , Food Preservatives/pharmacology , Antifungal Agents/pharmacology , Oils, Volatile/analysis , Microbial Sensitivity Tests , Food Contamination/prevention & control , Cheese/analysis , Food Preservatives/analysis , Fungi/isolation & purification , Fungi/classification , Fungi/drug effects , Antifungal Agents/analysisABSTRACT
The objective of this study was to evaluate the antifungal activity of nanoemulsions encapsulating essential oil of oregano (Origanum vulgare), both in vitro and after application on Minas Padrão cheese. Nanodispersions were obtained by the phase inversion temperature method. Cladosporium sp., Fusarium sp., and Penicillium sp. genera were isolated from cheese samples and used to evaluate antifungal activity. Minimal inhibitory concentrations of non-encapsulated and encapsulated oregano essential oil were determined, and they were influenced by the encapsulation of the essential oil depending on the type of fungus. The antifungal activity of the nanoencapsulated oregano essential oil in cheese slices showed no evidence of an effect of the MICs, when applied in the matrix. On the other hand, an influence of contact time of the nanoemulsion with the cheese was observed, due to the increase in water activity. It was concluded that nanoencapsulated oregano essential oil presented an inhibitory effect against the three genera of fungi evaluated. If environmental parameters, such as storage temperature and water activity, were controlled, the inhibitory effect of nanoemulsions of oregano oil could possibly be greatly improved, and they could be presented as a potential alternative for the preservation of Minas Padrão cheese against fungal contamination.
Subject(s)
Antifungal Agents/pharmacology , Cheese/microbiology , Food Preservation/methods , Food Preservatives/pharmacology , Oils, Volatile/pharmacology , Origanum/chemistry , Antifungal Agents/analysis , Cheese/analysis , Food Contamination/prevention & control , Food Preservatives/analysis , Fungi/classification , Fungi/drug effects , Fungi/isolation & purification , Microbial Sensitivity Tests , Oils, Volatile/analysisABSTRACT
Aflatoxins (AF) can be cumulative in fish tissues and can influence weight, length, feed intake and survival depending on the species. The aim of this work is to measure performance and aflatoxin levels in tissues of matrinxã (Brycon cephalus) fish chronically exposed to aflatoxin. Aflatoxin was incorporated into fish diets at the following levels: Control Feed + 0 µg AFB1 kg-1; A. Feed + 10 µg AFB1 kg-1; B. Feed + 20 µg AFB1 kg-1; C. Feed + 50 µg AFB1 kg-1. It was used one tank per treatment, each one with 150 juvenile fish, and three replicates within each tank were used for sampling, that was carried out monthly over a period of six months. Aflatoxin was quantified by HPLC in fish liver and muscle after clean up using immunoaffinity columns. Performance was evaluated by using weight, length, consumption and survival rate. Muscle and liver aflatoxin levels were below the limit of detection in all control samples. Aflatoxins B2, G1 and G2 were not detected in any tissues. Traces (values between limits of detection and quantification) of AFB1 were observed in liver tissue in treatment A from day 30 through 90, reaching 0.32 µg AFB1 kg-1 at 150 days of exposure. Treatment B presented traces up to day 60 and had, with a maximum level of 0.39 µg AFB1 kg-1 at 150 days of exposure. Treatment C had aflatoxin residues after day 30, with values ranging from 0.17 to 0.61 µg AFB1 kg-1 during exposure. Muscle samples only had traces of AFB1 in all treatments. Fish was affected by exposure to AFB1 with higher values (P<0.05) for weight and length in treatments A, B and C relative to controls. Therefore, results indicate that matrinxã do not accumulate AFB1 residues in edible tissues, but chronic exposure affects the species.
