Control of Listeria monocytogenes in whole milk using antimicrobials applied individually and in combination

Abstract

Dairy product recalls and dairy-related illnesses are often the result of contamination with Listeria monocytogenes, which can occur throughout the dairy production and supply chains. The use of antimicrobial compounds is one practical approach for controlling pathogen survival and growth in foods. The goal of this study was to use fluid milk as a model system to identify listeristatic or listericidal treatments that show promise for application in fluid milk and for further evaluation in other dairy products (e.g., cheese). Caprylic acid (CA), ε-polylysine (EPL), hydrogen peroxide, lauric arginate (LAE), and sodium caprylate (SC) were added individually or in combination to whole milk inoculated with L. monocytogenes at ˜4 log cfu/mL. Samples were stored at 7°C for 21 d, and L. monocytogenes counts were determined weekly. Inhibitory concentrations of LAE (800 mg/L) and EPL (100-400 mg/L), as well as SC and CA (3,200 mg/L each), were identified. The addition of EPL at 800 mg/L reduced L. monocytogenes counts by >3 log cfu/mL from initial inoculation levels after 21 d. Addition of hydrogen peroxide to milk reduced counts by >3 log cfu/mL from initial inoculation within 24 h (400 and 800 mg/L) or by d 7 (200 mg/L). Although the combinatory treatments of EPL + CA, EPL + LAE, and LAE + SC were characterized as indifferent, EPL + SC worked synergistically to reduce L. monocytogenes populations in milk over 21 d. Overall, these data identify potential antimicrobial treatments to control L. monocytogenes in milk and serve as a foundation for the continued development of antimicrobial controls for L. monocytogenes in dairy products.

Lactose oxidase: A novel activator of the lactoperoxidase system in milk for improved shelf life

“…Martin et al (2014) reported that the higher the concentration of H 2 O 2 in raw milk, the greater the antimicrobial effect on total bacterial count over time during storage at 6 and 21°C. Similarly, Listeria monocytogenes growth was inhibited in raw milk during 21 d at a concentration of 100 mg/L of H 2 O 2 , whereas at concentrations of 400 and 800 mg/L counts were reduced to undetectable levels within 24 h (Kozak et al, 2018). Other studies have reported bacterial inhibition due to the production of H 2 O 2 by enzymatic systems such as glucose oxidase-glucose in milk (Dionysius et al, 1992) and liquid whole egg (Dobbenie et al, 1995).…”

Short communication: Screening inhibition of dairy-relevant pathogens and spoilage microorganisms by lactose oxidase

“…Lactose oxidase generates hydrogen peroxide, a well-known antimicrobial compound, as a product of the oxidation of lactose to lactobionic acid (Nordkvist et al, 2007). Hydrogen peroxide has proven to be an effective antimicrobial in foods such as leafy greens (Moore et al, 2011), milk (Martin et al, 2014;Kozak et al, 2018b), and queso fresco (Kozak et al, 2018a), among others. However, the direct addition of hydrogen peroxide is not aligned with current consumer trends and is not always feasible (due to rapid dissipation) or permitted, depending on the product (Martin et al, 2014;Kozak et al, 2018b).…”

Applications of Edible Coatings Formulated with Antimicrobials Inhibit Listeria monocytogenes Growth on Queso Fresco

“…Antimicrobial treatments for incorporation in chitosan coatings were selected based on previous work (Kozak et al, 2017(Kozak et al, , 2018a and included: 25% ACSL, 5% HP, 5% LAE, 25% ACSL + 10% SC, and 5% LAE + 10% SC. Preparation and application of chitosan coating solutions were adapted from previously published methods Chen et al, 2012 were added directly to mixed chitosan solutions on a v/v basis.…”

“…), can further enhance their efficacy (Pranoto et al, 2005;Zivanovic et al, 2005;Duan et al, 2007;Beverlya et al, 2008;Jiang et al, 2011;Petrou et al, 2012;Guo et al, 2014;Shekarforoush et al, 2015;Paparella et al, 2016). Previous research has identified effective antimicrobial treatments for the control of L. monocytogenes in broth and whole milk including acidified calcium sulfate with lactic acid (ACSL), hydrogen peroxide (HP), lauric arginate (LAE), and sodium caprylate (SC) (Kozak et al, 2017(Kozak et al, , 2018a. However, application of these antimicrobials to the surface of QF as aqueous dips were comparably less effective in inactivating L. monocytogenes and inhibiting growth during storage (Kozak et al, 2018b).…”