The Chernobyl reactor accident on 26 April 1986 released large quantities of radioactive isotopes into the environment. These substances were largely deposited on the soil and from there entered the soil-plant-human and soil-plant-animal-human food chains. From a radiobiological point of view, the caesium isotopes

• Caesium-137 (Cs-137) with a half-life of approx. 30 years and
• caesium-134 (Cs-134) with a half-life of approx. 2 years

are of particular importance. These isotopes remain in the upper soil layers for many years in unworked soils with organic layers, such as forests. There they can be absorbed in particular by shallow-rooted plants, such as fungi, moss, grasses and some berry bushes. This fact explains the still high caesium content in some outdoor mushrooms, some berries and in wild meat from animals that live in the wild and feed on grasses and shrubs, such as deer.

The following list summarises the results of a measurement campaign by the AG Physikalische Umweltanalytik, in which the total caesium content of berries was investigated in 1994. The data have the form:

• "Berry name", description (origin, date of discovery or purchase) / CS

with the abbreviations:

• MHD = best before date
• CS = total caesium activity (Cs-137 and Cs-134) in Becquerel per kilogramme in ready-to-eat form.

For better readability, the measurement uncertainty is not stated. "CS < 1" means "below the detection limit of 1 Bq/kg".

With regard to the evaluation of the measurement results, the Working Group on Physical Environmental Analysis agrees with the recommendation of the Radiation Commission of the German Federation for Environmental and Nature Conservation (BUND). This recommendation contains the following orientation values for the total caesium load in the ingested food:

• Adults: 35 becquerels per kilogramme
• Infants and pregnant women: 10 becquerels per kilogramme.

The specified values should not be exceeded on average. A single or very infrequent consumption of highly contaminated food is therefore not a cause for concern.

Fresh fruit

• Green gooseberries, 26203 Wardenburg, purchase 16.7.94, weekly market / CS < 1
• Blueberries DEMETER, 31604 Raddestorf, purchase 16.7.94, weekly market / CS = 1
• Blueberries, Lüneburger Heide, purchase 16.7.94, weekly market / CS < 1
• Raspberries, 49377 Langförden, purchase 16.7.94, weekly market / CS < 1
• Redcurrants, 21641 Apensen, purchase 16.7.94, weekly market / CS < 1
• Redcurrants, Germany, purchase 12.7.94, plus / CS < 1
• Red currants, 49377 Langförden, purchase 16.7.94, weekly market / CS < 1
• Red wine grapes, Chile, purchase 12.7.94, plus / CS < 1
• Sour cherries, Altes Land, purchase 16.7.94, weekly market / CS < 1
• Sour cherries, Spain, purchase 12.7.94, plus / CS < 1
• Blackcurrants, 49377 Langförden, purchase 16.7.94, weekly market / CS < 1
• Gooseberries, Altes Land, purchase 16.7.94, weekly market / CS < 1
• White currants, 26203 Wardenburg, purchase 16.7.94, weekly market / CS < 1
• White wine grapes, Italy, purchase 12.7.94, Comet / CS < 1

Preserves

• Blackberries VALENZI, purchase famila, 26.7.94, best before 11.5.96 / CS < 1
• Cocktail cherries ODENWALD, purchase famila, 26.7.94, best before 31.12.97 / CS < 1
• Blueberries TITZ, purchase famila, 26.7.94, best before 11.3.97 / CS < 1
• Raspberries KING'S CROWN, purchase famila, 26.7.94, best before 31.12.96 / CS < 1
• Raspberries RIO BRAVO, purchase Combi, 26.7.94, best before 13.7.96 / CS < 1
• Raspberries VALENZI, purchase Combi, 26.7.94, best before 17.1.97 / CS < 1
• Cranberries KING'S CROWN, purchase WEZ, 14.7.94, BBD 31.12.97 / CS = 37
• Cranberries KÜHNE, purchase Combi, 26.7.94, best before 31.12.95 / CS = 25
• Cranberries VALENZIA, purchase famila, 26.7.94, best before 26.1.98 / CS = 39
• Forest blueberries NATREEN, purchase famila, 26.7.94, best before 31.12.96 / CS = 1
• Wild blueberries ODENWALD, purchase Combi, 26.7.94, best before 31.12.97 / CS = 2
• Wild cranberries BASSERMANN, purchase WEZ, 14.7.94, best before 31.12.96 / CS = 18
• Wild cranberries NATREEN, purchase WEZ, 14.7.94, BBD 31.12.96 / CS = 24
• Wild cranberries ODENWALD, purchase WEZ, 14.7.94, best before 31.12.96 / CS = 42

Jams

• Blackberry jelly, Schwartau HAUSFRAUENART, purchase famila, 26.7.94, best before 5.5.95 / CS < 1
• Dreifrucht, Zentis BELFRUTTA, purchase famila, 26.7.94, best before 23.3.95 / CS < 1
• Dreifrucht, TAMARA, purchase ALDI, 26.7.94, best before 11.1.96 / CS < 1
• Blueberry, Zentis BELFRUTTA, purchase famila, 26.7.94, best before 20.6.95 / CS = 2
• Blueberry, Göbber UNSERE BESTE, purchase famila, 26.7.94, best before 6.12.95 / CS = 13
• Raspberry, Schwartau MÖVENPICK GOURMET, purchase famila, 26.7.94, best before 20.4.95 / CS < 1
• Raspberry, Göbber SYMPHONIE GOURMET, purchase famila, 26.7.94, best before 12.1.95 / CS < 1
• Raspberry jelly, Schwartau HAUSFRAUENART, purchase famila, 26.7.94, best before 16.6.95 / CS < 1
• Elderberry jelly, Schwartau GROSSMUTTERS, purchase Combi, 26.7.94, best before 13.1.96 / CS < 1
• Sour cherry, Zentis ACHENER FRÜCHTLI, Kauf Combi, 26.7.94, best before 25.3.95 / CS < 1
• Sour cherry, Göbber EXTRA, Kauf Combi, 26.7.94, best before 9.9.95 / CS < 1
• Sour cherry, GÖBBER, Kauf Combi, 26.7.94, best before 12.2.95 / CS < 1
• Sour cherry, Schwartau MÖVENPICK GOURMET, Kauf famila, 26.7.94, best before 29.4.95 / CS < 1
• Sour cherry, SCHWARTAU, purchase famila, 26.7.94, best before 28.8.95 / CS < 1
• Sour cherry, TAMARA, purchase ALDI, 26.7.94, best before 7.1.96 / CS < 1
• Blackcurrant, Zentis DIE ECHTE, purchase famila, 26.7.94, best before 10.9.94 / CS < 1
• Blackcurrant, MARMELINCHEN, purchase ALDI, 26.7.94, best before 29.7.95 / CS < 1
• Blackcurrant jelly, Schwartau HAUSFRAUENART, purchase famila, 26.7.94, best before 3.5.95 / CS < 1
• Gooseberry, Zentis BELFRUTTA, purchase famila, 26.7.94, best before 24.3.95 / CS < 1
• Forest fruit, Schwartau MÖVENPICK GOURMET, purchase famila, 26.7.94, best before 22.4.95 / CS = 6