Risk Mitigation of E. coli O157 and its Intimin (eaeA) and Shiga Toxin (stx2) Gene Expression in Chilled Chicken Fillets Using Chitosan Nanoparticle Loaded with Lysozyme
Risk Mitigation of E. coli O157 and its Intimin (eaeA) and Shiga Toxin (stx2) Gene Expression in Chilled Chicken Fillets Using Chitosan Nanoparticle Loaded with Lysozyme
Aalaa S. Saad1*, Amira A. Elokle2, Dalia Y. Youssef2, Neven M. Omara2, Samr Kassem3
ABSTRACT
Chitosan nanoparticles loaded with lysozyme (CS-LZ-NPs) are gaining popularity as an alternative approach for inhibiting foodborne pathogens. This study aimed to evaluate the antibacterial activity of synthesized Chitosan nanoparticles (CS-NPs) and CS-LZ-NPs against E. coli O157 in chilled chicken fillets and relative eaeA (Intimin), stx2 (Shiga toxin) expression. The average particle size was 250 nm and 281.4 nm for CS-NPs and CS-LZ- NPs and the PDI (polydispersity index) was 0.09 and 0.58, respectively. TEM imaging showed uniformity and ranging in size from 13.1 to 17.6 nm and 15.6 to 19.5 nm for CS-NPs and CS-LZ-NPs, respectively. In the SRB (sulforhodamine B) assay, CS-NPs, and CS-LZ-NPs showed no toxicity at concentrations ranging from 50 to 450 µg/mL for both nanoparticles. The MIC of CS-NPS and CS-LZ-NPS were 2.5 mg/mL and 0.312 mg/mL, respectively. As well, the number of viable E. coli O157 in fillets with CS-NPs and CS- LZ-NPs gradually decreased significantly (P<0.05) on chilling than the control. Moreover, eaeA and stx2 relative gene expression decreased until the 10th day, reaching 0.3 and 0.41 in the CS-LZ-NPs group and 0.5 and 0.48 in the CS-NPs group. Also, the treatment with either CS-NPS or CS-LZ-NPS did not affect the average sensory score of the chicken fillets.
Keywords | Chicken fillet, Chitosan nanoparticles, E. coli O157, Gene expression, Lysozyme, Toxins
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April 2024
Vol. 12, Iss. 4, pp. 586-801
