diffusion through some food packaging materials

Regulatory approval of ozone has increased commercial interest in the development of applications to ensure produce quality and safety. However, ozone sometimes fails to inactivate microorganisms on packaged produce and this may be a consequence of poor diffusion into packages. Gaseous ozone (900 +/- 12 mu L/L) was applied to several common plastic films with a range of ventilation areas and diffusion through them determined. A semi-quantitative method using the reaction of ozone with indigo trisulfonate or with indigo carmine dye solutions was used. Dye de-colorization occurred relatively rapidly (in less than 1 h) after exposure to ozone, indicating that it diffused through all tested materials. Although the extent of ozone diffusion followed the sequence of high-density polyethylene > polypropylene > low density polyethylene, differences among them were small and not significant (P>0.05). Ozone diffusion was also determined through a low density polyethylene film with ventilation areas of 1.3, 5.2, and 10.4% created by circular holes 6.5 mm in diameter. Gradual but modest increases in ozone diffusion occurred as the ventilation area increased. (C) 2011 Elsevier B.V. All rights reserved

residues on table grape berries

The persistence of residues of some fungicides, commonly applied in table grape vineyards to reduce bunch rot, was investigated during the cold storage of 'Thompson Seedless' table grape stemmed berries in atmospheres of air or 0.3 mu L/L ozone enriched air. Grape berries were sprayed with a mixture of boscalid, iprodione, fenhexamid, cyprodinil, and pyrimethanil solutions, dried in air for 24 h, and packed in plastic clamshell containers in expanded polystyrene boxes. The boxes were stored either in ozone or in ambient air atmosphere (2 degrees C, 95% RH) for 36 d. Residue analyses were done initially and at 12-d intervals using gas chromatography-mass spectrometry. Residues of boscalid, iprodione, fenhexamid, and pyrimethanil declined during storage in air, but cyprodinil residues did not change significantly during 36-d storage. Storage in the ozone atmosphere markedly accelerated the rates of decline of fenhexamid, cyprodinil, and pyrimethanil, but not those of boscalid or iprodione. At the end of storage, degradation of fenhexamid, cyprodinil, or pyrimethanil was 1.6-, 2.8-, or 3.6-fold higher, respectively, in the ozone atmosphere compared that in air. Despite their structural similarity, pyrimethanil declined more rapidly in an ozone atmosphere than cyprodinil. Fenhexamid declined in both air and ozone more rapidly than the other fungicides; at the end of storage period, only 59.2% or 35.5% of the initial residue remained after air or ozone storage, respectively. Our results have shown that gaseous ozone treatment during storage has a great potential for degrading contemporary fungicides related to table grape production. (C) 2011 Elsevier B.V. All rights reserved

Imazalil residue loading and green mould control on citrus fruit as affected by formulation, solution pH and exposure time in aqueous dip treatments

Please help populate SUNScholar with the full text of SU research output. Also - should you need this item urgently, please send us the details and we will try to get hold of the full text as quick possible. E-mail to [email protected]. Thank you.Journal Articles (subsidised)AgriwetenskappePlantpatologi