Health officials in Portugal have found the reason why more than 200 people fell ill recently after eating a type of bread.

The Directorate-General of Health (DGS) said 209 cases were associated with the consumption of broa de milho (a type of cornbread) in some regions of the country since mid-July.

The clinical symptoms of cases directed a laboratory investigation that considered the short incubation period and duration, the literature, and had contributions from experts.

Patients presented similar symptoms, including a dry mouth, vision issues, dizziness, mental confusion, and decreased muscle strength. Symptoms were observed between 30 minutes to two hours after eating food. In most cases, they were classified as mild, but more than 40 people required hospital care.

Tropane alkaloid findings
In samples taken from flour, bread, and patients, the tropane alkaloids atropine and scopolamine were detected at very high levels.

An investigation found strong evidence of contamination with seeds from the Datura genus, a plant that may be present as weeds in cultivated fields. Such contamination can occur during harvesting.

This work involved regional departments of public health, the Economic and Food Safety Authority (ASAE) and the General Directorate of Food and Veterinary Affairs (DGAV).

Following the incident, DGAV is to release a guide for producers, to ensure better control of this plant in fields and after harvest.

In early August, officials warned people not to eat broa de milho in certain parts of the country but said the product “is, and should continue to be, an integral part of the Portuguese diet.”

Authorities restricted the use of raw materials in the manufacture of the implicated products.

The advice to avoid broa de milho in Leiria, Santarém, Coimbra, and Aveiro has now been lifted.

Authorities said this is due to the lack of new suspected cases and the absence of potentially contaminated products on the market. Businesses and consumers were thanked for following the earlier recommendations.

DGS added that a risk assessment does not justify maintaining the guidance to avoid broa de milho in the identified regions but if new cases arise the situation could change.