Sound the alarm: the plastics industry has discovered that your eco-friendly reusable shopping bags may be making you sick.

The Environment and Plastics Industry Council stated Wednesday that a study it funded shows reusable bags “pose a public health risk” due to high counts of yeast, moulds and bacterias in dirty reusable bags.

According to Dr. Richard Summerbell, who spoke on behalf of EPIC, potential hazards include “food poisoning … bacterial boils, allergic reactions, triggering of asthma attacks, and ear infections.”

But B.C. provincial health officer Dr. Perry Kendall said reusable bags do not pose a serious public health risk if consumers treat bags as they would cutting boards or food preparation surfaces, and wash them regularly and dry them well.

The study was conducted on approximately 24 reusable bags obtained through “street intercepts throughout downtown Toronto.”

“We randomly selected bags from consumers,” said Cathy Cirko, vice-president of EPIC.

Cirko said the study was “material neutral,” and couldn’t say what materials the randomly tested bags were made of.

Most of the bags tested were less than a year old and 44 per cent were in daily use.

Of the bags tested, 64 per cent were contaminated with “some level of bacteria,” about 30 per cent had “elevated bacterial counts” higher than what is considered safe for drinking water, 40 per cent of the bags had yeast or mould, and some of the bags had “an unacceptable presence of coliforms.”

Summerbell, a microbiologist, said one example of how serious contamination could occur is through droplets leaking from bloody meat in a reusable bag that could transfer from one surface to another.

More than 50 per cent of the tote bags studied were used for multiple purposes. Summerbell said that transporting gym clothing, running shoes, athletic equipment and diapers in the same bags used for grocery shopping increases risks of contamination.

Summerbell said “a reusable bag might be stored in a folded manner that creates a moist environment that is perfect for bacterial growth.”

He said: “A reusable bag is a hygiene item. If you clean it, no problem.

“A bag starts off being microbiologically sterile. If it’s kept in a clean condition, it stays close to that level … what was found in the study was about half of the bags were not being kept in sterile conditions.”

Kendall said: “The basic lesson from this is that if you’re really unhygienic, anything can be a risk.”

“Obviously a damp, wet cloth bag is going to be a breeding ground for moulds. I’m not surprised they found them in shopping bags.

“At this point it’s not a public health risk, it’s just about the importance of hygiene, and the same basic principles that apply to cutting boards and separating raw foods from cooked foods.”

Kendall, who grew up in England, said, “I grew up with reusable shopping bags, everybody used them well into the ’60s, or wicker baskets. People laundered their bags periodically.”

Lindsay Coulter of the David Suzuki foundation said: “It doesn’t surprise me or scare me that bags going from your grocery store to the trunk of your car could harbour bacteria.

“Keep them in a dry ventilated area and wash them once a week.”

dryan@vancouversun.com