The phrase "harmful microorganisms" refers to very tiny living things that can cause damage or illness to our bodies. These microorganisms, such as bacteria or viruses, can make us sick if they enter our bodies. Full definition
The freezing process does kill parasites, though it may not make the salmon completely free of harmful microorganisms. (healthyeating.sfgate.com)
They protect our body from harmful microorganisms (infection) and monitor our own cells to eliminate those that work improperly (cancer). (nationalnutrition.ca)
If they are not properly cleaned and well maintained, they become the perfect breeding grounds for mold and other harmful microorganisms. (thankyourbaby.com)