Modeling the inhibitory effects of zinc chloride on table olive related yeasts

The effect of ZnCl2 on green Spanish‐style table olive packaging, a presentation style dependent behaviour

“…On the contrary, the area under the yeast curve corresponding to the control (with potassium sorbate) was significantly lower than any treatment containing ZnCl 2 . This behaviour indicates a relatively low inhibitory effect of yeast by ZnCl 2 with respect to that observed in synthetic culture media where the inhibition was clearly achieved . Furthermore, the present trend contrasts with that observed during the shelf life of directly brined cracked Aloreña de Málaga olives in which yeasts clearly decreased (the curve of areas was concave) in the presence of ZnCl 2, and particularly when the concentration was 0.75 g L −1 ZnCl 2 .…”

“…Overall, data from this work show that the inhibitory effect of ZnCl 2 on yeasts has been slightly less effective than that of potassium sorbate (control) during a large part of the study. These results contrast with the strong inhibitory effect observed in a synthetic medium for ZnCl 2 . In any case, complete inhibition of the yeast population was not achieved in the control either, although its curve was below those of treatments containing ZnCl 2 during a marked period of time.…”

“…These species were also found by Rodríguez Gómez et al during the storage of Hojiblanca and Manzanilla olives intended for the elaboration of ripe olives in an acidic medium. Apparently, the survival of P. galeiformis in these packed olives cannot only be related to the presence of sorbate or ZnCl 2 , although Bautista‐Gallego et al described P. galeiformis as a well‐resistant yeast to ZnCl 2 in a synthetic medium, with values for the minimum inhibitory concentration (MIC) of around 0.15 g L −1 , but also to its good adaptation to the table olive environment …”

“…Moreover, its presence in the continuous alcoholic fermentation reduced the size of flocks, increased the tolerance to alcohol and temperature, decreased the production of glycerol, and accumulated in the yeast dry matter . Zinc oxide has also shown antimicrobial activity against Listeria monocytogenes , Salmonella enteriditis and Escherichia coli O157:H7, while ZnCl 2 has shown a strong inhibitory effect on table olive related yeasts . In cracked Manzanilla‐Aloreña olives, a type of directly brined table olive elaboration, the presence of ZnCl 2 led to a marked reduction in Enterobacteriaceae and yeast populations and an improvement in the nutritional value of the product .…”

“…10 Zinc oxide has also shown antimicrobial activity against Listeria monocytogenes, Salmonella enteriditis and Escherichia coli O157:H7, 11 while ZnCl 2 has shown a strong inhibitory effect on table olive related yeasts. 12,13 In cracked Manzanilla-Aloreña olives, a type of directly brined table olive elaboration, the presence of ZnCl 2 led to a marked reduction in Enterobacteriaceae and yeast populations 14 and an improvement in the nutritional value of the product. 15,16 Furthermore, zinc sulfate and zinc perchlorate completely inhibited fungal growth and their ability to produce mycotoxins from toxigenetic strains of Fusarium graminearum, Penicillium citrinum and Aspergillus flavus; the production of conidia of all fungi was reduced and hyphae damage was also noticed.…”