In the first week of September, The Local carried an article about the outbreak of Legionnaire's disease in Umeå and Linköping.

In the article we reported that “the outbreak has been linked to an old spraying system for fruit and vegetables at the OBS supermarket in Umeå”.

Miatech Inc, an American company based in Oregon which specialises in the production of misting and humidification systems for fruit and vegetables, has asked us to clarify that the incident in Umeå was caused by an ultrasonic fogger, not a mister or a sprayer. We are happy to oblige.

They explained to us that in order for the Legionella bacteria to be inhaled by humans, the water droplets must be smaller than 5 microns in size. No spraying systems can produce droplets smaller than 10 microns. Miatech’s spraying systems create water particles of around 40 microns, which cannot be inhaled, and which cannot therefore transmit Legionella.

We translated the word “befuktningsanläggningar” as “spraying system”, when of course it should have been “fogging system”.

The company kindly pointed out to us the following:

“In North America more than 90% of all public grocery stores now use produce misting. No store uses fogging, because people might die and that would be irresponsible.”

Indeed, during the last 20 years around 30,000 misting systems have been operating around the world without one single incident of Legionella being reported, according to Miatech.

Miatech also pointed out that the system cannot have been one of theirs, since they have not sold any systems in Sweden.

We trust this clarifies the matter.