Study: 75% of Madrid hashish contaminated with faecal bacteria

A researcher at the University of Madrid conducted a study on hashish which he obtained on the black market, and thus found that most of the hashish sold on the streets of Madrid is unfit for human consumption. Studies like this highlight the dangers of a lack of regulation of cannabis products.

Contaminated hashish

Pérez Moreno, a pharmaceutical researcher at the School of Veterinary Medicine at the Complutense University of Madrid, became a cannabis user for the purposes of the study. He went out himself to buy some hashish from 90 different dealers and then analyzed it. The study concluded that «most of the hashish sold in the Community of Madrid is unfit for human consumption, primarily due to microbiological criteria, and poses a health hazard.».

In fact, 75% of the samples analyzed contained significant amounts of’Escherichia coli, a bacterium that indicates fecal contamination. The vast majority of Spanish hashish comes from neighboring Morocco, where smugglers ingest it, expel it on the other side, and then sell it. While passing through the body, the piece of hashish becomes contaminated with bacteria. This is particularly true of hash sold in olive-shaped pieces (93% of the samples analyzed were contaminated). The team also analyzed hash in slab form and found fecal bacteria in only 30% of the samples.

Fecal bacteria are not the only health risk. In 10% samples, Pérez’s team detected traces of fungi of the genus Aspergillus which can cause infections and allergic reactions. «A Aspergillus »can be fatal if left untreated," the researcher says. In 2012, Energy Control, a Spanish project aimed at reducing the risks associated with drug use had 170 samples of hashish analyzed and had found fungi in 4% of them. The research did not focus on bacteria in this case.

Causes and Dangers

This contamination may be harmless, but according to the study, the amount of bacteria found in each gram is about 500 times higher than the limits set by U.S. and European health authorities for fruit or tea. Pérez Moreno also points out that for some patients with cancer or autoimmune diseases, self-medication can be dangerous because the risk of infection is greatly increased due to a weakened immune system.

«This type of contamination is due to the fact that hashish is illegal in Spain. In a regulated market, this would be unthinkable,» points out Claudio Vidal of’Energy Control. «It’s clear that this is a public health issue. The levels of bacteria we observed are outrageous,» says biologist Inmaculada Santos, who participated in the study. «The problem isn’t just from inhalation. Hashish is constantly handled with the hands,» she explains. «The filters on joints are hollow. You’re not just inhaling smoke but also particles,» adds Perez.

The vast majority of hashish sold in France and Spain is from Morocco and is therefore likely to have been ingested and then excreted in feces. France and Spain are the top two countries in the European Union in terms of cannabis use. It is therefore possible that many users are exposed to these risks. Claudio Vidal, however, qualifies the study’s findings: «This is a small number of samples, and we do not know how many different types of hashish are currently in circulation. We cannot know whether the results are representative of what is sold in the Community of Madrid or in Spain.».