Sterlization by Bleach, Water Purification Tablets

[AaronEax123]

I am doing a project and I would like to keep my tools sterile, I have a plastic measuring spoon that I need to handle microwaved nutrient agar with, but I believe there may be bacteria and microorganism on it already, would it be wise to dip the spoon in some freshly poured bleach and let it dry and keep away from air movement for 5-15 minutes and then use to handle the agar on as I do not want any other types of bacteria or contaminants to interfere with my project results. as well I ordered some water purification tablets from Israel called "Taharymayim" and I would like to purify some tap water with it for my control in my project as I am determining which types of water do bacteria grow the best/fastest in: tap, bottled, or purified; the tablets state that it contains chlorine in it so if i used these tablets on my tap water would it count as really "purified" and bacteria free? thanks!

[JorgeLobo]

Bleach won't sterilize and even if it did - the device would be recomtaminated by from the air.
Try using heat - get a staibless steel spoon and flame it before use - same with water. Though spores will survive, boiling will kill most vegatative cells- keep it covered to cool.

Microwaving may not sterilize your media.

[michimichi]

yes, chlorine wont sterilize your tools, it can only lessen the number of organisms on it.as for your water, buy a distilled water instead.

[JorgeLobo]

Not sure the depth of your experiment - science fair vs. research - but I do suggest you read the literature on this subject. Of course the presence of chlorine wiil affect growth but it's also important to consider the inoculum you'll use and what protcol for recovery. Some bugs grow well in distiled water approahing milion per ml in a relatively short time whereas others grow slowly but are recovered betterafter long incubation on media of limited nutrition.