Officially, you should be using food-grade silica gel to dehydrate foods; this is why some countries have a certification system that distinguish between food and non-food grades.
That said, though, many countries consider silica gel to be harmless enough that they do not distinguish a food-grade version. And even the FDA, which recommends using silica gel marked food-safe, doesn't actually regulate it at all as long as the weight of the gel is less than 2% of the food that it accompanies (also, if you look at that regulation, you can see that some gels can even be used in food). So, while you should use food-grade products where you can get them, the risk associated with using non-food-grade appears to be low.
The exception here is color-changing silica gels. If the gel you used is blue or orange and changes color in the presence of moisture, it has highly toxic substances (like cobalt) that should be nowhere near food.