Every now and again we get a call about sour smelling enzymes.  Have they gone bad?  No, but for some reason systemic enzymes can have a really sour milk odor to them.  Unfortunately the smell seems to vary from lot to lot without any rhyme or reason.  These enzymes haven’t gone bad.  Most brands of systemic enzymes, including Vitalzym, have at least an 18 month shelf life.  And even then, the enzymes don’t actually go bad,  but rather they begin to lose strength.  It’s best to keep your enzymes stored at room temperature, and though they may have an odor, they’ll be fresh for many, many months.  For more information on systemic enzymes, be sure to visit us at http://www.expressnaturals.com/Enzymes_1_s/39.htm.