Food and Herbal Additives

In the past it was a very common thing for people to get sick from food due to the fact that there was not great refrigeration and things of that nature.  Of course I am talking about in the late 1800s and early 1900s when an ice box was the only real way to get any refrigeration.  Salt curing meats and growing your own vegetables to can would be how you would steer clear from getting sick from toxic or spoiled foods.  One would think that with all sorts of technologies that food allergies and illnesses would be no more, especially if those problems are stemmed by the additives and...