Placing a jar of feces on a pedestal next to him, billionaire philanthropist Bill Gates made a plea Tuesday for the safe disposal of human waste as he kicked off a �Reinvented Toilet� Expo in China.

�You might guess what�s in this beaker � and you�d be right. Human feces,� the former CEO of software giant Microsoft said. �This small amount of feces could contain as many as 200 trillion rotavirus cells, 20 billion Shigella bacteria, and 100,000 parasitic worm eggs.�

He went on to say that pathogens like these cause diseases that kill nearly 500,000 children under the age of 5 every year.

More than 20 companies and academic institutions are exhibiting new toilet technologies at the three-day expo in Beijing, from self-contained toilets to a small-scale, self-powered waste treatment plant called the Omni Processor.

The Bill and Melinda Gates Foundation that Gates co-founded with his wife has spent more than $200 million since 2011 to stimulate research and development of safe sanitation technology.

�The technologies you�ll see here are the most significant advances in sanitation in nearly 200 years,� he said, according to a text of his prepared remarks.

UNICEF estimates that 4.5 billion people worldwide do not have access to safely managed sanitation, and that 480,000 children under 5 die every year from diarrhea, primarily in South Asia and sub-Saharan Africa. There is an economic cost too: Poor sanitation cost the world nearly $223 billion in 2015, according to a study by Oxford Economics and Japanese toilet maker Lixil.

Gates left the feces on display for about 10 minutes before removing it, his point made.

(AP)