Evaluation of strategies for reducing patulin contamination of apple juice using a farm to fork risk assessment model

The numerous studies conducted so far on the issue of patulin contamination have focused mainly on aspects like growth of Penicillium expansum, patulin production under different conditions and the influence of processing on the patulin concentration in apple juice. The purpose of the present study was to collect the necessary information and to develop a quantitative risk assessment model (QRAM) in order to evaluate different strategies to reduce patulin contamination. For apple juice (AJ) production 3 types of apples are considered, namely fresh apples, apples stored under cold air (short term storage) and apples stored under controlled atmosphere (CA) (long term storage). The QRAM described the complete chain from the picking of apples until storage of produced AJ. In comparison to a traditional chemical analysis, the QRAM was found accurate in predicting the concentration of patulin in cloudy and clear AJs commercialised in Belgium. Simulation of the model demonstrated that the use of apples stored under CA contributes to a large extent to the patulin contamination of AJ. Since apples stored in CA are used from more or less January onwards, AJ with high patulin concentration can be produced from January onwards. It would be useful in this respect to take this into account when sampling plans are made by apple juice producers in the framework of their HACCP-system and by governments and control agencies when monitoring programmes are elaborated. The duration of deck storage between the delivery at the apple juice producer (AJP) and the processing of the apples had a large influence on the patulin concentration, and this effect was more pronounced for apples stored under controlled atmosphere compared to apples stored under cold air. The duration of the deck storage should therefore be considered as a Critical Control Point (CCP) within HACCP-systems. Also the application of a sorting step was evaluated to be efficient to reduce the high patulin concentration in AJ. Therefore, a combination of the 2 most effective measures (namely sorting out apples with an infection lesion larger than 10cm² and a reduction of the volume of CA apples) was tested and resulted in a reduction to levels below 25μg/kg in 99.7 to 99.9% of the clear and cloudy apple juices, respectively. It is therefore advisable to include a sorting step prior to processing, when apples stored in CA are used.