You have isolated a gram-positive bacterium with low g + c content. it was a contaminant in unpasteurized milk. it infected a pregnant woman, and now you are worried that her child will be stillborn. what bacterium is it?

The gram-positive bacterium having low G+C content contaminating the unpasteurized milk is Listeria monocytogenes. This bacterium can be found in the dairy products. When an individual is infected it can cause mild infections, but when it infects a pregnant female, it is capable of causing serious harm to the health of the woman as well as the fetus. In most cases, it may cause stillbirth or abortion.

Hence, the answer is 'Listeria monocytogenes'.

a physical change is being made.