No, campden/k-meta inhibits yeast, it will not kill them with the standard winemaking dose. To kill off live yeast in a fermenting wine you would have to add so much SO2 that the wine would be undrinkable.
If you have live yeast in solution along with a fermentable sugar source then those yeast will ferment that sugar until all sugar is gone or alcohol toxicity is reached and the yeast die off. This is under ideal conditions of course: temp, pH, TA, nutrient, etc. Campden/k-meta is also used to eliminate both free chlorine, and the more stable form, chloramine, from water solutions (i.e., drinking water from municipal sources), and will act as an antioxidant. You will find Campden/meta in a sodium or potassium base, most use the potassium derived product.
Campden/k-meta will kill bacteria.
Also, always check your package for dosing directions since they do come in different strengths--we tend to talk of one Campden tablet per gallon or 1/4 tsp k-meta granules per five gallons.
Potassium sorbate, sold as a chemical or behind a product name such as Sorbistat K, is a commercial wine stabilizer that should be used in conjunction with Campden or its active ingredient, potassium metabisulfite. In other words, it works better with sulfites present than without, and it works better than sulfites alone. Potassium sorbate disrupts the reproductive cycle of yeast. Yeasts present are unable to reproduce and their population slowly diminishes through attrition Potassium sorbate is typically added in the amount of 1/2 teaspoon per gallon of wine. Sorbic acid results and stabilizes the wine. Usually the crushed Campden and potassium sorbate are dissolved in a cup or two of the wine to be stabilized and stirred thoroughly. Allow the stirred wine to sit a few moments and look for small white lumps of undissolved powder. If present, continue stirring until the wine is clear without any undissolved lumps. This is then added to the larger batch and stirred in well.
* Very important to write date on packages when opening and store properly. I keep mine in airtight container, in refrig, and replace every six months. Any excess six month old Campden/k-meta is used around the house as a sanitizing solution. It probably keeps longer but I just stick with every six month rotation. Nothing bites more than finding out your sorbate was expired, and your wine fermented all the sugar you backsweetened with.
