Hundreds of people swarmed Vancouver’s streets Saturday, taking aim at genetically modified foods – and one of their largest manufacturers – as part of a worldwide day of protest.

Chants of “Say no to GMO!” could be heard as protesters braved the rain to speak out against genetically modified foods and their potentially harmful effects on health.

“Human beings have never eaten these before,” said protester Warren Brander. “We don’t have enough studies to say if they’re safe or not. I wouldn’t want my family eating them.”

Brander said one of the protests’ goals is for the federal government to introduce mandatory labeling of genetically modified foods.

“I feel like that’s a basic right to know,” he said.

Many European countries already force manufacturers to label GMO foods, but it’s practically impossible for Canadians to know if what they’re eating has been genetically enhanced.

“It doesn’t give us an option as a consumer as to whether we want to consume those types of foods,” said Cherie Doucette. “It’s important to come out here and show that the average citizen, it’s important to them.”

Aside from lobbying the government, protesters said they were also calling out one of the largest producers of modified seed – Monsanto – for having a monopoly on much of the world’s food supply.

“I think if people are given the choice of buying GMO or non-GMO, then it will take the power away from Monsanto,” an unnamed protester said. “If they know what they’re buying, they’ll certainly make the right choice, and educated choice.”

Monsanto has said that it respects people's rights to express their opinion on the topic, but maintains that its seeds improve agriculture by helping farmers produce more from their land while conserving resources such as water and energy.

Genetically modified plants are grown from seeds that are engineered to resist insecticides and herbicides, add nutritional benefits or otherwise improve crop yields and increase the global food supply.

Health Canada and the U.S. Food and Drug Administration have both taken the official stance that GMO food is safe to consume.

In 2011, Health Canada said that it wouldn’t call for mandatory labeling unless it received information that there’s a health concern.

“March Against Monsanto” organizers said protests were planned for more than 250 cities around the globe, including several cities in Canada.

With a report from CTV British Columbia’s Scott Roberts and files from The Associated Press