Several customers have asked us recently why our cheese contains sodium benzoate, a preservative. Sodium benzoate generally considered safe, and is permitted in small quantities not only in the U.S., but also in the E.U. which generally is more strict with food purity. But there are some scientists who suggest that sodium benzoate may be hazardous.
We don’t use sodium benzoate by choice, it’s an ingredient in the rennet we use. Rennet is the coagulant that separates the curds from the whey. Traditionally, rennet was extracted from a calf’s stomach. We prefer to use rennet produced by microbes, which results in a vegetarian product. However, in order to lengthen the shelf life of the microbial rennet, the manufacturer adds sodium benzoate.
How much sodium benzoate does our cheese contain? We don’t know exactly how much sodium benzoate the manufacturer adds, but 0.1% is listed by one source as an upper limit. We add 3.5 ml of rennet to 50 gallons of milk to produce our chevre. That makes the amount of rennet in the milk roughly .002% and the amount of sodium benzoate in the milk approximately .000002% or 20 parts per billion.
Put another way, soft drinks that use sodium benzoate as a preservative could contain a maximum of 0.24 ml of the preservative. The rennet we add contains a maximum of 0.0035 ml sodium benzoate, so each half pound of cheese would contain no more than 0.0009 ml sodium benzoate. You’d have to eat almost 3,000 pounds of cheese in a sitting to get the maximum amount of sodium benzoate you could ingest in a single soft drink. Which brings to mind one of the old Alka-Seltzer commercials. (“I can’t believe I ate the whole thing!”)
We understand the concern with added chemicals, and we’re trying to make cheese without even that small amount of sodium benzoate. The supplier we’ve been using offers organic rennet in large quantities– five gallon containers. Our chevre requires 3.5 ml of rennet, and a full batch of Gouda requires 70 ml. Five gallons of rennet would produce more than 5,400 batches of chevre, or more cheese than we would make in 50 years! According to the supplier, organic rennet has a shelf life of only 4-5 months. That’s not a practical solution.
We tried buying organic rennet in a 1 liter size. We discovered that it wasn’t really organic, even though it was labeled as such. A second supplier advertises organic rennet on their website, but an inquiry revealed that it wasn’t really organic, either. (Home cheesemakers beware!)
We’ve now talked to a supplier who says he will start offering organic rennet in quarts. If it becomes available, we will certainly use it.