Evaluating the effects of zinc chloride as a preservative in cracked table olive packing

This survey studies the influence of different zinc chloride concentrations (0.050, 0.075, and 0.100%, wt/vol) on the shelf life of "Aceituna Aloreña de Málaga" table olives. The Enterobacteriaceae population significantly (P ≤ 0.05) decreased in treatments containing 0.050 and 0.100% ZnCl(2), and those with 0.075% ZnCl(2) had also lower average counts than those observed under the usual packaging conditions (0.12% potassium sorbate). Lactic acid bacteria increased for treatments with 0.050 and 0.075% ZnCl(2), but in the presence of 0.100% they practically disappeared at the end of the shelf life period (∼3 months). With respect to yeasts, populations of these microorganisms significantly decreased with the first two concentrations (0.050 and 0.075%) but showed a slight increase in the presence of 0.100% of ZnCl(2), although remaining markedly below populations observed with potassium sorbate packing. The use of this chloride salt also led to products with higher concentrations of sugars in brine because of its selective microbial inhibition. Finally, olives treated with 0.075% ZnCl(2) showed an improved sensory profile.