What methods are there to reduce microbial contamination excluding handwashing?

Exposure to gamma or beta radiation will usually do the trick.

Handwashing is the number one method of microbial control.
Handwashing is important enough that the hospital where I work will write you up if you are caught going from one patient to another without washing your hands.

However, if you are talking about disinfecting surfaces, such as countertops, bath tubs etc. use good old household bleach.
A 10% solution will work nicely on those fomite surfaces.

It depends on what materials you are talking about.
Cover your mouth and nose when sneezing or coughing.
Wash the cutting board and knife after cutting meat.
Refrigerate food immediately after a meal.
Make sure your water system is safe.
Wash fruits and vegetables.
Cook meat to a temperature that will kill bacteria.
Ground meat has more chance of getting contaminated, cook longer.
Keep prepared foods in the refrigerator (salads, desserts)
Do not use utensils used by others.
Clean up kitchen after a meal. Wash down with an antibacterial solution after a process that could spread microbes.
Don't touch face or hair when preparing food.Dispose of contaminated materials properly.
Wear a face mask when needed.
Buy inspected meat.
Wash poultry and fish.
Teach children sanitation rules.
there are many storage rules for foods in a restaurant.
Sanitize bedding and clothing after a contagious illness.




I took a whole college course on this, there is too much to write.