so angry with my mil

i came home early from work today and saw my mil scooping baby ziyi's porridge from the slow cooker. and i saw her rinsing her bowl with tap water ONLY. i was so mad and asked why didn't she rinse it with hot water?? and u know what her reply was? 

"aiya, sometimes i'll forget wan. she's been doing okay what...so nothing la"

i was FUMING MAD! then i started my lecture... "u know ar.. tap water is contaminated with dunno-what bacteria, germs..blah..blah..blah..".....which lasted for about few minutes.

of course, her face turned black immediately but i didn't give a damn coz this concern my daughter! that surely affected my mood. i didn't even smile to my cutie-pie while feeding her her porridge. yes, i took over the spoon from my mil. aaargghhh!!!

is it really okay to NOT sterilise or at least rinse baby utensils with hot water??