The Bioprox bioprotective cultures are effective in inhibiting: Debaryomyces Hansenii yeast Kluyveromycess yeast Yarrowia lipolytica Candida kefir Pichia yeast Mucor hyemalis mold Aspergillus niger mold Pencillium roqueforti Clostridium Listeria monocytogenes E.Coli Fresh cheese and continental cheese: cheddar, gouda, edam, manchego, etc. Composition: Lactobacillus. Hobbyist use: 1/4 tsp per 3 gallons of milk. Can make up to approximately 10 to 12 batches. This product is not required to be refrigerated in shipment, only upon arrival. If you are concerned about post office misdelivery, late delivery, hot weather at your delivery zip code or inability to put in refrigerator upon arrival, you can add an ice pack in shipment for $3.75 more, plus the cost of the weight of this shipping. If you order more than one item, there will be one ice block for the entire order. You will need to select this as a separate purchase in our Amazon store as we do not automatically ship with an ice pack. Our ice pack option is also not available for shipment with other Amazon seller’s products. Pursuant to Amazon's policy, we cannot accept back food-based, perishable items and we do not issue credits, refunds or replacements. We accept no liability for undue application by buyer.