Hate mealy apples and soggy french fries? Science can help. Food companies are increasingly turning to chemistry and physics to tackle the problem of food waste. There are spray-on peels and chemically enhanced sachets that can slow the ripening process in fruit and digital sensors that can tell when meat is safe to consume. Packets affixed to the top of a takeout box use thermodynamics to keep fries crispy. Experts say growing awareness of food waste has led to an uptick in efforts to mitigate it. More than one-third of food produced in the U.S. goes uneaten; much of that winds up in landfills.