Suchergebnisse

High moisture content, relative humidity, temperature and environment rich in oxygen (O2) are the main factors for tree nuts to get infected by fungi and so aflatoxins (AFLs) contaminated. During storage and commercialization dry Brazil nuts packs need to maintain their safety and quality. Modified atmospheres in storage (macro-environment) and packaging (micro-environment) have been used to prolong food shelf life by reducing O2 concentration with inhibitory gases or, more recently, by adding O2 absorber pads. This work reports the application of O2 atmosphere reducing methods on stored shelled Brazil nut packs aiming fungi and AFL degradation as well as hygienic conditions improvements. The methods applied were: (a) ozone - O3, (b) carbon dioxide - CO2 and (c) O2 absorber pads with and without vacuum. Nuts were submitted to microbiological tests (fungi, aflatoxigenic strains, yeast and bacteria), moisture content and AFLs analysis. From all O2 reducing atmosphere evaluated, the best performance was obtained with O3. A reduction on fungi growth (1.8 x 104 cfu.g-1 to 2.6 x 10 cfu.g-1) and yeast destruction after the first month of storage were registered. Also O3 was the only nut treatment that was able to degrade AFLs. None of the spiked (AFLs: 15 ppb) nut samples O3 treated had AFLs detected up to the LOQ of the method (0.36 μg.kg-1 for AFB1+AFB2+AFG1+AFG2) i.e., much lower than the allowed by the European Union regulation (MRL: 4 and 2 ppb for total and AFB1, respectively), thus producing safer nuts. All other treatments stabilized and/or inhibited microorganisms growth. Add CO2 and O2 pads played an important role on nut quality. Further study will be carried out in order to adjust O3 concentration and application conditions for longer period of storage.