But according to the New York State Health Department, these temperature-testing precautions are not enough.
"There are too many uncertainties involved about what the food in the dumpsters have been exposed to," said spokesman Peter Constantakes. "We have concerns about the practice mainly because anything that goes into trash has exposure to any sort of food pathogens, including rat droppings, pesticides, or household cleaners that can be a potential health risk."
Nelson, who employs the temperature-testing techniques, said: "People need to take the same reasonable health precautions with food outside of a store as they do inside of a store. It took me two years of doing this before I considered myself sophisticated enough with it to discern which foods were cold enough or hot enough to take."
Currently, Nelson is unemployed. She carefully lives off her savings and helps to organize bi-monthly trash tours and monthly Freeganism feasts in New York City, part of an effort to eliminate food waste in the U.S. -- an estimated 34 million tons annually, according to the Environmental Protection Agency.
Around 20 people attended the monthly feasts in NYC, said Nelson. The most recent one included a "dumpstered" spread: grilled veggies, fruit salad, coleslaw and "many of the kind of things you can find at a summer picnic."
"Since at least 2001, I remember George Bush saying, 'if you love America go out and buy because it will support the American economy,'" Nelson said. "But if you love the economy, if you love the world, for God sake don't buy because it's 100 percent unsustainable."