Sodium propionate is found in nature and can also be manufactured by industry. It is a common food additive. Sodium propionate kills mold and certain bacteria, so it is often added to baked goods and other perishable products. It is safe to add small amounts of sodium propionate to food.
Artificial sodium propionate
is often used as a preservative in the food industry. Because it prevents mold and some bacteria from growing, it can extend the shelf life of packaged baked goods. The law says sodium propionate is safe as a food additive Sodium propionate is also used in packaging and processing cheese products to prevent mold growth. In addition, sodium propionate is used as an additive in animal feed to inhibit bacterial overgrowth in the stomach of livestock.
A study in 1967 in the journal of bacteriology first suggested changes in the metabolism of aspergillus. This strain of mold grows on grains and baked goods. An article in the October 2007 issue of the journal of food protection suggested that listeria was a common contaminant in packaging cheese and luncheon meat, and that sodium propionate could slow or stop the growth of the bacteria listeria. So you can use sodium propionate as a food additive, and the sodium propionate in the food is so low that you don't feel it when you eat it.
According to Sciencelab coms safety data sheet for sodium propionate, if treated with pure sodium propionate, it will directly irritate the skin. But because the average person will not be exposed to pure sodium propionate, it is unlikely to cause skin irritation. You're more likely to eat products contaminated with mold or bacteria than you are at risk of taking propionic acid. If you're really worried about propionate, bake your own bread or buy fresh bread.