alright hey everybody dis ducked row when this video we're going to talk about the pH and its effect on growth we've already covered oxygen and temperature these kind of things so just real quickly the pH scale goes from zero to fourteen seven is neutral ending the pH under seven would be acidic anything with a pH above 7 would be alkaline or basic so an acidophiles gonna love an acidic environment a neutral file is gonna love that neutral pH area around seven give or take and alcala file is gonna like more alkaline temperature so first of all there's a tremendous diversity with microorganisms they're organisms they grow anywhere basically but we only care about the ones that like to grow in us and on our food right so most bacteria are going to grow at a pH between six point five and seven point five makes sense you know that's the world around us is like that our bodies are like that so make sure you note that most bacteria like to grow between a pH of six point five and seven point five hovering right around neutral there are very few microorganisms very few bacteria that can grow under a pH of four so there are some acidophiles there are some organisms that can grow at a pH of one but they're not going to grow in you or your food so we don't really care about them the reason that we we love the fact that a low pH will inhibit almost all microbial growth and especially pathogens this is why fermenting your food is such a powerful food preservation method so when you turn cabbage into sauerkraut or you make kimchi or make yogurt these kind of things fermenting things lowers the pH greatly because of all the lactic acid added to that to the food and that's what makes it a preservation method I don't know how long a cabbage would keep sitting out or even in the refrigerator but I've had sauerkraut that I keep in the fridge just to see how long it goes before it before it turns in it and hasn't after years so so the fact that most microbes don't like a lower pH is the reason fermentation is such a great food preservation method alright just you know molds and yeast they generally can grow along a larger pH range but they generally like a pH closer to five to six so bacteria like 6.5 to 7.5 molds and yeasts a little more acidic one last really important thing so whether you're trying to keep microbes alive in a lab or hoping they don't survive remember that just like us microorganisms produce a civic byproducts as a there as are acidic products or compounds as a byproduct of their own metabolism so we generate acids that have to be dealt with we have buffers then we have you know urinary and respire trait mechanisms to deal with those acids microbes basically sputum inter environments so as microbes are growing they basically poison their own environment by spewing out acids which lowers the pH which they don't like so this is one of the main reasons that we don't we don't live on a planet just a mile deep with bacteria they poison their own environment by releasing these acidic byproducts that lower the pH so yay us right all right so that is the effect that pH is going to have on microbial growth have a wonderful day be blessed