According to Ben Urbonas, president of the Urban Watersheds Research Institute, these nutrient contaminants tend to be more of a problem in closed water systems,like lakes, where concentrations can build up.

VOA: standard.2010.08.04

And if food is anything you eat, it gives you a nutrient, then basically everything satisfies the criteria for food; not everything in the world, but most things would.

若不论吃什么,只要提供营养就是食物,那基本上没有什么不满足食物的定义,倒不是说一切东西,至少绝大部分都满足

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

This particular website has this free nutrient analysis On the website people may choose to get involved in and there may be charges for those things, I don't really know, but there may be and then they may ask you for identifying information, but it's your option to do that.

网站的营养分析服务,在该网站,人们可以选择使用其他服务,当然,那些可能是收费的,我不是很确定,可能有收费服务,并要求验证个人信息,但这由你自己选择

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选