Today a federal court in NJ ruled against the companies from China responsible for the pet food...?

Companies from foreign countries can't just sail across the ocean with a boatload of stuff and start peddling it. Because manufacturers in China most certainly entered into legally binding contracts with U.S. companies, the manufacturers in China undoubtedly agreed to be bound by U.S. law, prosecutable in U.S. courts of law. Your other questions: penalty and enforcement of penalty. Wars have been started over less offense than a foreign company refusing to abide by the terms of an agreement, or in this case, a decision by a U.S. judge. The implications of the Chinese not carrying out whatever penalty or restitution is required are many. Barring war, we could place an embargo on certain Chinese- made products.