"Ever go out with a group of friends and try to figure out what you want to eat?" Jim Cramer asked "RealMoney" radio show listeners Tuesday. "You know how difficult this can be. ... Now imagine that they're avoiding beef and chicken because they're worried about bird flu and mad cow disease," he said. Cramer cited the fact that medical experts around the globe believe that bird flu will hit the U.S. by the end of the year and that the U.S. Department of Agriculture confirmed that a cow in Alabama has mad cow disease, the third report in three years. Sure, you could think about selling companies such as Tyson Foods ( TSN), KFC parent company Yum! Brands ( YUM) and Hormel ( HRL), Cramer said. But he also wants to think about how to make some money, and that's by buying pork-related stocks. The two pure plays are Smithfield Foods ( SFD) and Premium Standard Farms ( PORK), he said. "This is where the obvious doesn't work," Cramer said, adding that Premium Standard, whose ticker is PORK, has been disappointing. Don't reach for it over Smithfield, even if it only sells for $17 a share while Smithfield sells for $28, he says, because Premium Standard is in reality a more expensive stock. The growth of a company is how Cramer judges whether it's cheap or expensive, not the actual stock price. And at $17 a share, he said that Premium Standard isn't growing as fast and isn't as good as Smithfield at $28. "When we compare the growth rates, Smithfield is much cheaper," he said. Plus, it's best of breed, which means that if the market takes the stock down it will most likely snap back, he added. Smithfield is the worldwide producer of pork, and demand should remain strong as long as we're worried about avian flu and mad cow, Cramer said.