You can't feed an animal by any poor quality products, including canned goods with expired period of validity. By the way, the specialists do not recommend giving your dog any tinned nutrition, intended for the people. The spices, conserving agents and Adepses from such canned goods negatively influence the organs of digestion of an animal (the liver can be harmed too). Specialized canned goods for dogs and cats can be the exception.
Botulism is an acute toxic infection, by this high-gravity disease are sick not only people, but also animals: dogs, cats, agricultural animals and others.
Bacillus Botulinum, located in canned goods, provokes this disease. The bacillus can be resistant to conditions of an environment; therefore even the canned goods can harm your pet. The microbes work out a very powerful toxin (poison) provoking the common intoxication of an organism (a vomiting, diarrhea, defeats of a nervous system, paralyses). The death rate in this case quite often reaches 100 %.
Sometimes in such cases the modern medicine is powerless. There are some single- and polyvalence vaccines, which can protect your pet from botulism. But the best way to protect your animal from botulism and other nutritional poisonings is to feed it by good-quality nutrition; you should observe all the instructions of the food storage and all the requirements of hygiene especially in a hot season.