Assessment of accumulative DPA residues throughout storage and packing facilities

The aim of this trial was to increase the amount of data available at present and to support the results obtained from the original study (A 02-13a). The project will also give an indication if a decontamination procedure could be followed for cold stores to reduce the risk of DPA cross-contamination. Fruit were sampled from new and old cold stores to determine if the wooden bins or cold stores could be a source of DPA cross-contamination. Cut-out paint samples and floor and wall cotton wool swab samples were sent for analyses to determine the levels and risk of DPA cross-contamination. A decontamination procedure with silver peroxide was also conducted to evaluate if DPA residues in a cold store is lower after the decontamination.

Fruit stored in old cold stores and in wooden bins were determined to be a low to no risk for DPA cross- contamination. This result supports the results obtained in the original project (A 02-13a).

Paint samples and cotton wool swabs from the walls and floor did not show clear trends between cold stores that stored DPA treated fruit and cold stores that did not. DPA levels were also very low in the cotton wool swab samples, and residue levels extracted from paint samples varied, suggesting that one cannot use swab or paint samples to determine (rank) if a cold store will be a high risk of DPA cross- contamination, or not.

Due to the low DPA levels in the cold stores, it could not be determined if decontamination with silver peroxide was successful or not.

From the data it was evident that there is DPA residues in cold stores. However, the low DPA residue levels on available surface areas were low compared to the volume of the cold store and the volume of fruit that are stored in the commercial cold stores. This could be the reason for the low to no levels of DPA detected on fruit stored in old cold stores and wooden bins that was evident in this trial and also the original project (A 02-13a).