Ruling #1 - This is an extension of the earlier ruling re: salt. This rule will be extended to include any naturally occurring mineral that is used in food production. Thus baking soda, gypsum, and other food-use minerals can be use for processing foods up to 15 days prior to the beginning of the challenge.
Ruling #2 - This ruling is regarding the use of molds and yeast strains grown for specific purposes. You may purchase a starter, culture, etc. of any microbe, but must process it through at least 3 generations with at least one day of rest in between cultures. The second and third generations of the culture must be made on cultivated products only. For example - you can buy a packet of Red Star yeast at the local store and use it to make a loaf of bread on Tuesday, save a bit and make a second loaf (using cultivated products) on Thursday, save a bit and make a third loaf of bread which is 'challenge approved'.
Ruling #3 - The equal substitution rule - should you gather a mineral in the wild of questionable purity, you may make an equal substitution of food-grade material, which can be used during the challenge. Thus salt boiled from the waters of the Atlantic can be substituted for an equal weight of table salt, crushed shells can be substituted for food-grade calcium carbonate, etc.