I wouldn't draw the conclusion that Oxypowder won't work from this experience. There are many questions I would ask first. I would wonder if the food was eaten very close to the time the Oxypowder was taken. If not then it may not have come in contact with the food you are seeing. (The Oxypowder is recommended to be taken at bedtime, preferably on an empty tummy.) Also, I don't know about the chemistry of it, but perhaps oxypowder is effective at dissolving old fecal matter, but can't fully dissolve a piece of apple in one go. This would be an interesting question for the doctor on the oxypowder site on their forum before drawing conclusions. It would be interesting to see if they have a valid response for this.