Safflower and bitter melon extracts on suppression of biogenic amine formation by fish spoilage bacteria and food borne pathogens

Abstract

Safflower (Carthamus tinctorius) and bitter melon (Momordica charantia L.) ethanolic extracts for controlling growth of fish spoilage bacteria (Acinetobacter lwoffii, Pseudomonas oryzihabitans, Enterobacter cloacae, Shigella spp., Morganella psychrotolerans and Photobacterium phosphoreum) and food-borne pathogens (Staphylococcus aureus, Klebsiella pneumoniae and Salmonella Paratyphi A), and their biogenic amine production were examined in anchovy infusion decarboxylase broth (AIDB). Bacterial load in AIDB was between 8.1 and 8.9 log CFU/ml. Bitter melon generally restricted growth of bacteria (p < 0.05). Bacterial load in the medium was not associated well with biogenic amine production. All bacteria had a high ability to form biogenic amines in AIDB. Significant discrepancies were noticed among groups in ammonia and biogenic amine production by bacteria (p < 0.05). A. lwoffii and P. phosphoreum were main bacteria produced the highest level of histamine (254.05 vs. 234.39 mg/L). Among food-borne pathogens, S. aureus was found stronger tyramine producer, with value of 736.53 mg/L. Bitter melon and safflower extract led approximately 9 and 12 fold lower histamine accumulation by S. aureus. The study result showed that bitter melon extract had more obvious effect, particularly for suppressing ammonia and toxicologically important biogenic amines production by bacteria, and thus could be suitable antimicrobial agent in food systems.