Radiocaesium contamination in samples of black blueberry jams and comparison between organic and non-organic products

Still more than 30 years after the Chernobyl accident, foodstuff based on black blueberries (Vaccinium myrtillus) with relevant 137Cs activity concentrations are still found in the European Union market. Moreover, recently, mass media reported that food products based on black blueberries produced in UE were rejected by Asian markets because the 137Cs activity concentration was greater than 100 Bq kg-1. It is known that Ukraine, Belarus and Russia are great exporters of black blueberries: there is a strong suspicion that the berries are collected also from the most radio-contaminated areas of these countries and introduced in UE markets. For this reason, about 40 samples of jams, marmalades, stewed fruits and other food preparations based on black blueberries were analysed by high resolution gamma spectrometry with high purity germanium detectors to measure 137Cs and 134Cs activity concentration. All the food preparations of the study have been collected in supermarkets and in local stores of northern Italy. 134Cs, as expected following its half-life, was less than minimum detectable activity in all samples. 137Cs activity concentration was widely variable among samples: the minimum, mean and maximum concentration were 1, 54 and 162 Bq kg-1, respectively. The activity concentrations found in these products were corrected for the radioactive decay and reported to the same date. The activity concentration in fruits was calculated from fruit percentage content reported on the product label. In fruits used for marmalades, jams and stewed fruits, 137Cs activity concentration up to 230 Bq kg-1 was found. In a sample of blueberries in syrup, 137Cs activity concentration in blueberries was 450 Bq kg-1. The results found in organic jams and in non-organic jams were compared using parametric and non-parametric tests to find possible differences between the two groups.