MythBusters 2005x22

Join the MythBusters as they head to a California mine to test an ancient Chinese military myth – a subterranean sonar system that could allegedly detect and intercept an invasion from below. Then, armed with an incubator, agar plates and boundless enthusiasm, the guys aim to cook up the truth about a popular food fable. If food has been on the floor for less than five seconds, is it still safe to eat?