No abstract

The use of PET bottles for packaging soft drinks and mineral waters is still growing world wide. The production process for these bottles is improving constantly. These improvements are focussed on bottles with better barrier properties, higher inertness and higher heat stability. One of the factors determining the quality of PET bottles is the release of acetaldehyde into the product during storage. A literature survey was conducted on the odour and taste detection threshold of acetaldehyde in water. A method is described t o rapidly determine the concentration of acetaldehyde in water up t o a level of 1 pg/I. This method was used t o determine the concentration of acetaldehyde in mineral water during storage in PET bottles. In still water no acetaldehyde could be found, whereas the concentration of acetaldehyde in carbonated mineral water increased steadily upon storage. Model experiments were performed t o find an explanation.

As part of a multi-client project, the potential public health risks of the reuse of polyethylene terephthalate (PET) refillable bottles (PRBs) following possible misuse has been investigated. Participants in the project provided data and information from previous studies conducted independently at contract laboratories. These studies were sponsored by the clients in order to provide further research data on PET containers and their safety. In this report, the results of five of these studies along with the results of a recent study carried out at TNO are compiled and reported. PET refillable bottles were exposed to 62 contaminants, including pesticides, that a consumer could potentially store in bottles. After storage with a contaminant under well defined conditions, the bottles were washed, filled with a simulated beverage, and stored for various lengths of time. The beverage and in some cases the bottle wall were then analysed for the presence of the contaminants. Toxicological evaluation of the analytical results from these tests on contaminant residue remigration showed that even under exaggerated exposure conditions, there was no public health concern. Only one compound, parathion, remigrated to a level that required a more in-depth risk evaluation, and under the most conservative assumptions, it too presented no real health hazard. Additionally, current detection systems employed to ensure product quality detect a wide variety of contaminants, including commercial formulations of parathion. Data developed in this paper are consistent with the finding that PRBs can be safely reused. For preventing negative effects on product quality (e.g. taste), however, good manufacturing procedures including visual and electronic inspection systems are required to eliminate abused bottles.

This work is the second part of a milk study evaluating the effect of package light transmittance on the vitamin content of milk, in this case on UHT whole milk. The milk was stored at three different light intensities in polyethylene terephthalate (PET) bottles with varying light transmittance as described by Saffert et al. (2006). Changes in the vitamin A, B 2 and D 3 content were monitored over a storage period of 12 weeks at 23°C. Losses in vitamins A and B 2 were most pronounced in completely transparent PET bottles exposed to the highest light intensity. In these bottles, a reduction of the light intensity reduced the vitamin A loss from 88 to 66%, while in the case of vitamin B 2 the complete decomposition was just delayed from 4 to 8 weeks storage. The vitamin D 3 losses in clear PET bottles were almost independent of the light intensity. For pigmented PET bottles, the impact of package light transmittance and light intensity differed for each vitamin. An increase in package light transmittance and light intensity was found to be most decisive for vitamin B 2 stability. In the case of vitamin D 3 , only the increase in light intensity was found to be of relevance, whereas for vitamin A stability the influence of increased package light transmittance and light intensity could not be clearly observed. In dark-stored 'control' samples, the analysed vitamins were almost stable.

This work is the third and last part of a milk study evaluating the effect of package light transmittance on the vitamin content of milk, in this case on fortifi ed UHT low-fat milk. The milk was stored under light with an intensity of 700 lux in polyethylene terephthalate (PET) bottles with varying light transmittance to monitor the changes in the vitamin A, B 2 and D 3 contents over a storage period of 12 weeks at 23°C. Milk packed in pigmented PET bottles with the lowest light transmittance, which was stored in the dark under the same experimental conditions, served as the 'control' sample. In clear PET bottles, a reduction of 93% of the initial content was observed for vitamin A and 66% for vitamin D 3 , while the vitamin B 2 content was completely degraded. In all pigmented PET bottles, the vitamin retention was only slightly higher; the losses ranged between 70 and 90% for vitamin A, between 63 and 95% for vitamin B 2 , and between 35 and 65% for vitamin D 3 depending on the pigmentation level. In the dark-stored 'control' sample, a 16% loss could be observed for vitamin A, while the level of vitamins B 2 and D 3 remained almost stable.