The influences of natural zeolite (cliptinolite) on ammonia and biogenic amine formation by food-borne pathogen

In this study, the influences of zeolite at different doses (1 and 5%) on ammonia and biogenic amines production by Aeromonas hydrophila, Escherchia coli, Enterococcus faecalis, Listeria monocytogenes, Klebsiella pneumonia, Pseudomonas aeroginosa, Staphylococcus aureus and Salmonella paratyphi A were investigated in three different amino acid (histidine, tyrosine and arginine) decarboxylase broth. Gram positive bacteria produced ammonia above 52 mg/L in histidine decarboxylase broth (HDB), whilst ammonia production by gram negative bacteria ranged from 111 mg/L to 391 mg/L. Gram positive bacteria had an poor ability to produce histamine (<1mg/L) in HDB, E. coli produced highest amount of histamine (18.96 mg/L). Among the gram negative bacteria, the highest tyramine production was observed from E. faecalis (274 mg/L) in tyrosine decarboxylase broth, although Aeromonas hydrophila and E. coli produced considerable amount of tyramine, corresponded the value of 566.56 mg/L and 1657.19 mg/L, respectively. The result of the study showed that the effect of zeolite depends on type of bacteria, and amino acid decarboxylase broth in which bacteria was grown. Biogenic amine and ammonia production by bacteria were stimulated in the presence of zeolite in histidine decarboxylase broth, while zeolite had an inhibitor effect on production of ammonia and biogenic amine by bacteria in tyrosine and arginine decarboxylase broth.Key words: Zeolite, Food-borne pathogens, Histamine, Tyramine, Agmatine