Where is the majority of bacteria located in food that leads to food poisoning? I.E in most cases is it on the surface, or deep within the food (i.e in the case of "cooked" meat, or balanced?
This is a complex question and I can't cover it all. Different countries may sell meat and other food products processed in different ways. In the case of meat, it can be deep within the food in the case of ground meat. Use caution with ground meats, you should probably cook well done. Even cured meat can harbor listeria and other germs (follow the storage instructions on the package).
What about salads? Many counties include vinegar in the dressing, and this can help. The mayonnaise dressings can present more of a problem, keep refrigerated until ready to eat.
Meat cooking temperature, follow label directions. What about rare roasted (intact) meat? :) This is relatively less dangerous than ground meat. Follow instructions in a recent cookbook and/or information provided by your government for cooking.
With our complex grower, processing, and distribution networks today, there are simply no guarantees. Keep up with the news regarding recalls. Wash your vegetables and fruits well. Don't use a cutting board/ knife for both meat and vegetable preparation. Follow good kitchen sanitation. Practice frequent handwashing using plenty of soap and water.
Here is some information from the Univ. Mich. State. Primarily about salads but it has some good general information at the beginning. http://msue.anr.msu.edu/news/it_must_have_been_the_potato_salad
U.S. Govt. Meat, final internal temps. (Meat thermometer) https://www.foodsafety.gov/keep/charts/mintemp.html Using Fahrenheit.
This answer is not intended to be comprehensive.