Effect of Natural Zeolite (Clinoptilolite) on in vitro Biogenic Amine Production by Gram Positive and Gram Negative Pathogens

The effect of two levels of clinoptilolite (1 and 5%) on the production of biogenic amines (BA) and ammonia (AMN) by Gram positive (Staphylococcus aureus, Enterococcus faecalis, and Listeria monocytogenes) and Gram negative bacteria (Aeromonas hydrophila, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Salmonella Parathypi A), in tyrosine decarboxylase broth (TDB) was studied. A. hydrophila and E. coli produced the highest amounts of amines which were 1223.06 and 2627.90 mg/l, respectively. All strains were able to decarboxylate tyrosine to tyramine (TYR) with E. coli being the highest (1657.19 mg/l). A. hydrophila formed >50 mg/l histamine (HIS) while the other strains produced none or very low concentrations (<4 mg/l). Among Gram-positive pathogens, E. faecalis was characterized as the main amine producer (478.23 mg/l). Although dependent on bacterial strain and level used, the natural zeolite clinoptilolite can be used to decrease BA and AMN production by bacterial strains that are of health concern.Practical Applications: Uses of natural prodcuts for biogenic amines inhibition. Clinoptilolite was used to reduce the amounts of amines such as spermine, putrescine, and dopamine produced by pathogenic and spoilage bacteria

The effects of edible oil nanoemulsions on the chemical, sensory, and microbiological changes of vacuum packed and refrigerated sea bass fillets during storage period at 2 +/- 2 degrees C

WOS: 000494414700001The quality of vacuum packed sea bass fillets treated with nanoemulsions based on commercial oils (hazelnut oil, corn oil, canola oil, soybean oil, olive oil, and sunflower oil) at 2 +/- 2 degrees C was evaluated by sensory, chemical (thiobarbituric acid reactive substances, peroxide value, total volatile basic nitrogen, and free fatty acids), and microbiological (total psychrophilic bacteria, total Enterobacteriaceae counts, total mesophilic aerobic bacteria, and total lactic acid bacteria) methods. The chemical parameters of fillets treated with the nanoemulsions presented lower values than those of the control group. Microbiological assessment correlated with sensory analyses. The use of nanoemulsions extended shelf life of fish, 4 days for canola, corn, soybean, and hazelnut oils and 2 days for olive and sunflower treatment groups. The quality of chemical, sensory, and microbiological parameters of sea bass fillets was increased with the application of oil nanoemulsions as well as their shelf life. Practical applications Nanomulsions have been paid attention since they are known as ideal carrier for the delivery of lipophilic substances because of small particle size, the ease of preparation, high bioavailability, and long-term stability. They are also proven to be self-preserving antimicrobials due to the bound water in their structure and restricted available water to microorganisms. Nanoemulsion has been shown to extend the shelf life of different species of fish by lowering the value of biochemical parameters and also inhibiting microbial growth.Turkiye Bilimsel ve Teknolojik Arastirma KurumuTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TOVAG-113O379]Turkiye Bilimsel ve Teknolojik Arastirma Kurumu, Grant/Award Number: TOVAG-113O37