| dc.description.abstract | A zeolitic Imidazolate Framework-8 (ZIF-8) is a metal-organic framework (MOF) with good drug delivery capability. This study synthesized and characterized ZIF-8 nanoparticles encapsulated with trans-cinnamaldehyde oil (TC) and tested the antimicrobial effect of TC-encapsulated ZIF-8 nanoparticle complexes with 0.1mg/mL poly lysine (PL) coating (TC@ZIF-8_PL) against Escherichia coli (E.coli) O157:H7 on fresh spinach.
Several experiments were carried out to determine the antimicrobial activity of different mass ratios of TC-encapsulated ZIF-8. The optimal mass ratio of TC to ZIF-8 for nanoparticles complexes (0.5TC@ZIF-8_PL) was used for the studies. E.coli O157:H7 (ATCC 43895) strain, the most reported Gram-negative microorganism associated with foodborne outbreaks in spinach, was used as the target pathogen. Spinach samples were treated with 0.5TC@ZIF-8_PL nanoparticle complexes solution, 200 ppm chlorine, free TC, and sterilized distilled water (control). All sample groups were rinsed for 1 min, dried in a biosafety cabinet, weighted and packed in sample bags, and stored at 4°C for up to 15 days for shelf-life studies. The quality of spinach samples was assessed by monitoring changes in were moisture content (MC), water activity (Aw), color, pH, texture (firmness and work), vitamin C content, total carotenoid, and chlorophyll content.
Throughout the 15 days of storage at 4oC, spinach treated with 0.5TC@ZIF-8_PL had less (p<0.05) water loss, loss of total chlorophyll and total carotenoid, and change in pH. However, treatments did not prevent the reduction of vitamin C content and color degradation (p>0.05) and adversely affected spinach firmness. | |
