Better drug tests can stop cheaters. They also might punish innocent athletes.

That’s what Shelby Houlihan, a 2016 Olympian and the American record holder in the 1,500 and 5,000 meters, claims happened to her. In revealing the four-year suspension that will prevent her from running in Tokyo or even in the Paris Games in 2024, Houlihan said this week she had never heard of nandrolone, the anabolic steroid she tested positive for in December. On the night before her test, she said, she ate a burrito from a Mexican food truck that served pig offal, a meat that World Anti-Doping Agency studies showed could contain nandrolone.