Protein-rich foods like meat, milk eggs and fish are susceptible to pathogen growth.
Foodborne pathogens require a pH level of 4.6-7.5. Foods should be brought to a pH of 4.5 or below
The Temperature Danger Zone, at which pathogens can grow, is from 41-135 degrees Fahrenheit.
Food should not be left in the Temperature Danger Zone for longer than two hours.
Most pathogens are aerobic (require oxygen), so canning can prevent pathogen growth. Clostridium botulinum, which causes botulism, can grow in anaerobic environments (lacking oxygen), so improperly canned foods can be dangerous.
On the water activity scale from 0 to 1 (0 being dry, 1 indicating greater water availability), Foodborne pathogens grow best in foods that have a wa between 1.0 and 0.86. FDA regulations for canned foods require water activity of 0.85 or below.