A 30-year-old woman has become the third person to die from methanol poisoning in the Brazilian state of São Paulo, as the authorities investigate the source of the tainted drinks thought to be making people ill.

Bruna Araújo de Souza died after consuming a vodka drink at a bar more than a week ago, according to officials in the city of São Bernardo. It follows the deaths of two other men attributed to the same source.

To date, there have been a total of 225 confirmed cases of methanol poisoning in Brazil, predominantly in São Paulo. In response, health authorities have closed at least 11 businesses and seized over 10,000 bottles of alcoholic beverages.

The exact cause of the contamination remains unclear, prompting officials to advise the public to avoid consuming unlabelled drinks or those lacking safety seals or tax stamps. Methanol, a toxic type of alcohol used in cleaning products and other industrial applications, poses severe health risks even in small quantities.

Symptoms of methanol poisoning can mimic a hangover, which complicates early detection of the condition.

Ms. Souza was hospitalized critically, testing positive for methanol, and later confirmed brain dead. Among the deceased are Marcos Antônio Jorge Júnior and Ricardo Lopes Mira, both residents of São Paulo.

As health officials continue to probe potential methanol poisoning incidents, the manager of a bar in the bustling Paulista Avenue area has reported growing customer concerns, advising patrons to refrain from cocktails.

Among those affected, Brazilian rapper Hungria has shared a hospital photo on social media, urging caution when drinking. The Brazilian Health Minister, Alexandre Padilha, has described this situation as “abnormal and unlike anything else in our history regarding methanol poisoning.”