Antimicrobial pectin-gellan films: effects on three foodborne pathogens in a meat medium, and selected physical-mechanical properties

Abstract

It is first reported the elaboration and characterization of films (F2) containing 1% (w/v) citrus pectin, 0.2% (w/v) gellan gum, 0.5% (w/v) glycerol, CaCl2 5 mM, ethylenediaminetetraacetic acid (EDTA) 0.05 M and 90 (Arbitrary Units)/mL of an antimicrobial concentrated supernatant (ACS) from fermentation culture broths of the lactic acid bacterium, Streptococcus infantarius. The functional films inhibited the growth of Listeria monocytogenes, Escherichia coli and Staphylococcus aureus in “Barbacoa” medium in 7-day cultures at 35°C. “Barbacoa” is a highly appreciated Mexican meat product. In contrast, the control cultures exhibited bacterial-growths up to 107–109 (Colony-Forming Units)/g. An antimicrobial-activity synergy between ACS and EDTA was demonstrated. Some film-physical properties were modified by the EDTA-ACS incorporation [F2/control-film]: Young’s modulus (MPa), 1,394/707; elongation at break (%), 1.9/9.3; stress at break (MPa), 5.7/12.6; water vapor permeability (10–11 g m Pa−1 s−1 m−2), 3/20 and oxygen permeability (10–12 g m Pa−1 s−1 m−2), 1.9/1.2.

Keywords

• Bacteriocins
• biodegradable films
• EDTA
• food safety
• food packaging
• gellan
• meat products
• pectin