What is the difference between food fraud and food defense?

The difference between food fraud and food defense is that food fraud is done to make money, while food defense relates to acts that are done to create harm.  Food fraud perpetrators do not seek to cause harm, they seek to increase profits or otherwise benefit financially, so we say food fraud is economically motivated.  Food defense attacks are done to cause harm to consumers and companies.

What is the difference between intentional adulteration and food defense?

Intentional adulteration is the act of contaminating a food product with the intention of causing harm to the people who eat the food.  Food defense is a broader term that includes protection against adulteration of food, but can also extend to protection of equipment, assets and workers in food businesses.