A new case study considered a girl who went into anaphylactic shock after eating blueberry pie. She had a known history of allergy to penicillin, cow's milk, seasonal allergies and asthma.
Pie samples showed that the blueberries in the pie contained trace amounts of streptomycin, an antibiotic and common pesticide.
Studies into this type of link are rare and are even more so because the United States and Canada are some of the only countries that allow antibiotics in agriculture and processing. Recently, new Food and Drug Administration regulations may change that some.
The study, published in the Annals of Allergy, Asthma and Immunology in the September 2014 issue, had its lead author saying it was the first time fruits treated with antibiotic pesticides had been linked to allergic reactions. They and others acknowledge that the reaction is a rare case, even where antibiotic pesticides are common.