Use
Sodium propionate and calcium propionate are good preservatives, especially in food because very low toxicity has great advantages, bread usually calcium propionate, because bread is yeast fermentation, the use of sodium propionate can So that d increases dough, affecting yeast growth, will extend the time to face.
According to the Material Safety Data Sheet for sodium proprionate, as reported on ScienceLab.com, the pure chemical can irritate the skin if handled. However, since the general public would not come in contact with sodium propionate in its pure form, it does not likely present a risk. The risks of consuming sodium propionate are slight if you compare it to the possibility of consuming products that have mold or bacterial contamination. If you are worried about consuming sodium propionate, buy fresh bread or bake your own.
References: http://www.livestrong.com/article/501045-what-is-sodium-propionate/