A Comparative Study of Natural Antimicrobial Delivery Systems for Microbial Safety and Quality of Fresh‐Cut Lettuce

• Autores: Laura E. Hill, Daniela A. Oliveira, Katherine Hills, Cassie Giacobassi, Jecori Johnson, Harvey Summerlin, T. Matthew Taylor, C. Gomes
• Localización: Journal of food science, ISSN 0022-1147, Vol. 82, Nº 5, 2017, págs. 1132-1141
• Idioma: inglés
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• Resumen

  • Nanoencapsulation can provide a means to effectively deliver antimicrobial compounds and enhance the safety of fresh produce. However, to date there are no studies which directly compares how different nanoencapsulation systems affect fresh produce safety and quality. This study compared the effects on quality and safety of fresh‐cut lettuce treated with free and nanoencapsulated natural antimicrobial, cinnamon bark extract (CBE). A challenge study compared antimicrobial efficacy of 3 different nanoencapsulated CBE systems. The most effective antimicrobial treatment against Listeria monocytogeneswas chitosan‐co‐poly‐N‐isopropylacrylamide (chitosan‐PNIPAAM) encapsulated CBE, with a reduction on bacterial load up to 2 log10CFU/g (P< 0.05) compared to the other encapsulation systems when fresh‐cut lettuce was stored at 5 °C and 10 °C for 15 d. Subsequently, chitosan‐PNIPAAM‐CBE nanoparticles (20, 40, and 80 mg/mL) were compared to a control and free CBE (400, 800, and 1600 μg/mL) for its effects on fresh‐cut lettuce quality over 15 d at 5 °C. By the 10th day, the most effective antimicrobial concentration was 80 mg/mL for chitosan‐PNIPAAM‐CBE, up to 2 log10CFU/g reduction (P< 0.05), compared with the other treatments. There was no significant difference between control and treated samples up to day 10 for the quality attributes evaluated. Chitosan‐PNIPAAM‐CBE nanoparticles effectively inhibited spoilage microorganisms’ growth and extended fresh‐cut lettuce shelf‐life. Overall, nanoencapsulation provided a method to effectively deliver essential oil and enhanced produce safety, while creating little to no detrimental quality changes on the fresh‐cut lettuce. There is an immediate need in the food industry for antimicrobial treatments for fresh produce safety that effectively eliminate foodborne pathogens. Nanoencapsulation can provide a means to effectively deliver antimicrobial compounds and enhance the safety of fresh produce. This comparative study investigated the antimicrobial efficacy of free and nanoencapsulated natural antimicrobial systems against a foodborne pathogen, while monitoring their effect on fresh‐cut produce quality. Overall, nanoencapsulation provided a method to effectively deliver essential oil and enhanced produce safety, while creating little to no detrimental quality changes on the fresh‐cut produce. This study provides a side‐by‐side comparison among nanoencapsulation systems and their effect(s) on foodborne pathogen inhibition and also produce quality throughout shelf‐life that could be used for other natural antimicrobials with similar properties and fresh produce applications.