Antimicrobial Polyamide-Alginate Casing Incorporated with Nisin and ε-Polylysine Nanoparticles Combined with Plant Extract for Inactivation of Selected Bacteria in Nitrite-Free Frankfurter-Type Sausage.

Kazem Alirezalu,Mirian Pateiro,Milad Yaghoubi,Leila Poorsharif,José M Lorenzo,Shadi Aminnia,Halil Ibrahim Kahve,Paulo E S Munekata

doi:10.3390/foods10051003

Abstract

The effects of combining a polyamide-alginate casing incorporated with nisin (100 ppm and 200 ppm) and ε-polylysine (500 ppm and 1000 ppm) nanoparticles and a mixed plant extract as ingredient in sausage formulation (500 ppm; composed of olive leaves (OLE), green tea (GTE) and stinging nettle extracts (SNE) in equal rates) were studied to improve the shelf life and safety of frankfurter-type sausage. The film characteristics and microbiological properties of sausage samples were evaluated. Sausage samples were packaged in polyethylene bags (vacuum condition) and analysed during 45 days of storage at 4 °C. Control sausages were also treated with 120 ppm sodium nitrite. Polyamide-alginate films containing 100 ppm nisin and 500 ε-PL nanoparticles had the highest ultimate tensile strength compared to other films. However, 100 ppm nisin and 500 ε-PL nanoparticles decreased water vapour permeability of films. The results also revealed that nisin nanoparticles had significantly (p < 0.05) low inhibitory effects against Escherichia coli, Staphylococcus aureus, molds and yeasts and total viable counts compared to control and ε-PL nanoparticles. Furthermore, 1000 ppm ε-PL nanoparticles displayed the highest antimicrobial activity. Based on the obtained results, the films containing ε-PL nanoparticle could be considered as a promising packaging for frankfurter-type sausages.

Highlights

The results showed that tensile strength of calcium alginate films ranged between 63–67 MPa
Tensile strength in calcium alginate films incorporated with 500 ppm ε-polylysine nanoparticles (ε-PLN) was higher than other films (Table 1)
Our results revealed that Staphylococcus aureus counts in samples packaged in polyamide-alginate films incorporated with 500 ppm and 1000 ppm ε-PLN

Summary

Introduction

Contamination in meat products like sausages, especially by foodborne bacteria, is the main concern of meat producers [4]. Endeavour to reduce contamination in sausages using natural antimicrobials and antioxidants [7,8,9]. Increasing the safety of RTE products like sausages could be achieved using antimicrobial packaging [10,11,12,13,14]. Using natural antimicrobial compounds in packaging structures displays higher efficacy in comparison to direct use in the food matrix as an ingredient. The higher efficacy of active antimicrobial packaging may be attributed to the exposure of the food surface (where the risk of contamination is high) to antimicrobial compounds [15,16,17]

Methods

Results

Conclusion