Most cannabis sold on streets contains faecal matter, study finds

Average amount of faecal bacteria in each gram of resin in Madrid is 500 times higher than maximum legal limit for marijuana in the US

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The vast majority of cannabis sold on the streets of Madrid contains dangerous levels of faecal matter and is unfit for human consumption, according to a new study.

Manuel Pérez Moreno, a pharmacologist at the Universidad Complutense in Madrid, obtained 90 samples of cannabis resin from different drug dealers in the Spanish capital and found E Coli bacteria and Aspergillus fungus in a high proportion of the samples.

E Coli was present in 75 per cent of the samples he analysed – an indicator of faecal contamination. And 10 per cent were contaminated with Aspergillus – a dangerous fungus which can cause lung infections, particularly in people with underlying health conditions.

The average amount of faecal bacteria in each gram of resin was 500 times higher than the maximum limit set by the US legislation for marijuana or by the European regulation for fruit and tea, the study revealed.

Mr Pérez said the methods of trafficking the drugs are the chief reason for the high levels of contamination.

According to Spanish newspaper El Pais, he said traffickers wrap the cannabis resin in transparent film so they are the size of acorns, and ingest them, ball after ball, after having eaten yoghurt to neutralise stomach acids.

“When they arrive in Spain, they take laxatives and emit the acorns. And that goes on sale,” the pharmacist said.

He reported 93 per cent of the cannabis in these acorns contained E coli, and said 40 per cent of the acorns he bought smelled of faeces.

“Most of the hashish sold in Madrid is not suitable for human consumption, mainly due to microbiological criteria, and represents a danger to health,” he concludes in his study, published in the journal Forensic Science International.

Of all the samples obtained, 83.3 per cent were deemed unsafe for human consumption.

The study’s authors warned the dangers can affect vulnerable patients buying cannabis illegally to manage pain.

They said in recent years the number of people with cancer who smoke cannabis has increased as they attempt to reduce the side effects of chemotherapy.

“These patients have weakened immune systems, so an infection caused by the consumption of contaminated or adulterated hashish could be fatal,” the study says.

Combustion does not reduce all the risks, Mr Pérez explained.

“The filters of the joints are hollow. Not only do you suck the smoke, you also suck particles,” he said.

Biologist Immaculada Santos, co-author of the study and also a professor at the university told El Pais: “The amounts of bacteria we have observed are outrageous. The problem is not just inhalation. Hashish is being manipulated with his hands constantly.”

“It is clear that it is a public health problem.”