title: Effect of polymer/nanosilver composite packaging on long-term microbiological status of Iranian saffron (Crocus sativus L.).
abstract: Crocus sativus L. (saffron) is a valuable plant which is native to Iran. Saffron is the dried stigmata of the flowering part of the plant that is usually contaminated with different bacteria and fungi through production process. Antimicrobial properties of silver nanoparticles are well recognized. To survey the effects of nanosilver packaging on microbiological status of spiked, saffron samples over a six month period were chosen. Saffron samples from five regions of Khorasan province were purchased and de novo frequencies of microbial contaminants were determined using standard procedures. Totally 35 g of saffron was spiked with known numbers of four bacterial and two fungal species and packaged into one gram packets. The packaging materials consisted of polyethylene polymers containing 0, 400, 800, 1200 or 4000 ppm nanosilver (as Ag). Total and differential numbers of spiked microorganisms in the packaged saffrons were enumerated at initial and at six time points of seven, 14, 28, 64, 90 and 180 days. Baird-Parker agar (BP agar), Kenner Fecal (KF), Salmonella-Shigella agar (SS agar), Violet Red Bile Glucose Agar (VRBGA), and Sabouraud Dextrose agar (SD agar) media were used for enumeration of the six spiked microorganisms including Staphylococcus aureus, Enterococcus faecalis, Salmonella Enteritidis, Enterobacter species and Escherichia coli, Fusarium oxysporum and Aspergillus flavus, respectively. Direct antibacterial activity of the composites was also determined. De novo frequencies of microorganisms in five saffron samples were at acceptable levels with dominance of fungi species. Nanosilver embedded packages accelerated the reduction in live microbial numbers in saffron samples and the efficacy was the best in packages containing 4000 ppm nanosilver particles. Nanosilver packaging can significantly reduce microbial burden of saffron.
authors.affiliation: Department of Microbiology, Faculty of Science, Karaj Branch, Islamic Azad University, Karaj, Iran.
authors.forename: Mona
authors.initials: M
authors.lastname: Eslami
authors.affiliation: Department of Pathobiology, Faculty of Veterinary Specialized Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran.
authors.forename: Mansour
authors.initials: M
authors.lastname: Bayat
authors.affiliation: Department of Microbiology, Research Center for Molecular Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Amir Sasan
authors.initials: AS
authors.lastname: Mozaffari Nejad
authors.affiliation: Department of Microbiology, Faculty of Science, Karaj Branch, Islamic Azad University, Karaj, Iran.
authors.forename: Azar
authors.initials: A
authors.lastname: Sabokbar
authors.affiliation: Faculty of Veterinary Medicine, Islamic Azad University, Food Hygiene Sciences, Tehran, Iran.
authors.forename: Amir Ali
authors.initials: AA
authors.lastname: Anvar
keywords: Crocus sativus; Food preservation; Nanoparticles; Product packaging; Silver