Inactivation of Listeria monocytogenes ATCC 7644 on fresh-cut tomato using nisin in combinations with organic salts

Abstract

The inhibition of Listeria monocytogenes ATCC 7644 on fresh-cut tomato was investigated using nisin alone, and in combinations with organic salts. Nisin at a concentration of 5000 UI/mL was introduced alone or in combination with an organic salt (sodium citrate or sodium acetate each at 3 and 5 g/100 mL each) on fresh-cut tomato previously inoculated with 108 CFU/mL of L. monocytogenes ATCC 7644. Chlorine at 200 ppm was used as a control. The inoculated samples were incubated at different temperatures (4, 10 and 25 °C) and examined at 0, 24, 48 and 72 h. The effects of the antimicrobial treatments on quality parameters of tomato (pH, soluble solids, titratable acidity and vitamin C) were also evaluated, and colour parameters were observed at the lowest storage temperature for 10 days. Both nisin and the organic salts inhibited growth of L. monocytogenes, but the combinations of two compounds were more effective. The nisin–sodium citrate (5%) combination was significantly (p ≤ 0.05) effective, while chlorine was least effective against L. monocytogenes. The quality parameters were substantially retained, especially at 4 °C, suggesting good shelf stability at a low temperature. These results substantiate the use of the cheap and eco-friendly approach to reducing this pathogen of health concern in common fresh produce.

Evaluation of Sanitizing Methods for Reducing Microbial Contamination on Fresh Strawberry, Cherry Tomato, and Red Bayberry

“…To reduce microbial contamination, washing is a key sanitization step in the fresh-cut produce production chain (from farmland to dining table, Figure 1 ) ( Meireles et al, 2016 ). Many sanitizers have been evaluated for their ability to inactivate pathogens on fresh-cut fruits and vegetables ( Oms-Oliu et al, 2010 ; Abadiasa et al, 2011 ; Keskinen and Annous, 2011 ; Luo and Oh, 2016 ; Oladunjoye et al, 2016 ). SH at concentrations of 50–200 mg/L is commonly used as a commercial sanitizer to remove microbiota from fresh fruits, vegetables, and fresh-cut produce ( Beuchat et al, 1998 ).…”

Influence of temperature and pH on the production of biosurfactant, bacteriocin and lactic acid byLactococcus lactisCECT-4434

“…Currently, the most widely studied and industrially exploited bacteriocin is nisin, which is produced by certain strains of the probiotic bacterium Lactococcus lactis, is classified as a lantibiotic, contains 34 amino acids and has a molecular weight of 3.5 kDa (Arauz et al, 2009;Oladunjoye, Singh, & Ijabadeniyi, 2016). Nisin is able to inhibit pathogens and contaminants and is the only bacteriocin internationally legalized for use as a natural biopreservative of foods, since its intake does not exert toxic effects to the human body, does not alter the ecology of the gastrointestinal tract, and, then, does not present the same risks related to the use of antibiotics (Yoneyama & Katsumata, 2006).…”

The effect of ultrasound treatment in combination with nisin on the inactivation of Listeria innocua and Escherichia coli

“…1 a-c). The effect of nisin is expected, as it is widely known to act on Listeria species [25] , [75] , [76] , [79] , [80] . The lack of effect of ultrasound suggests that L. innocua is resistant to ultrasound treatment under the conditions studied.…”