Enabling Cost-Effective Screening for Antimicrobials against Listeria monocytogenes in Ham

Abstract

Ready-to-eat (RTE) meat products, such as deli ham, can support the growth of Listeria monocytogenes (LM) which can cause severe illness in immunocompromised individuals. The objectives of this study were to validate a miniature ham model (MHM) against the ham slice method and screen antimicrobial combinations to control LM on ham using response surface methodology (RSM) as a time- and cost-effective high-throughput screening tool. The effect of nisin (Ni), potassium lactate sodium acetate (PLSDA), lauric arginate (LAG), lytic bacteriophage (P100), and Ɛ-polylysine (EPL) added alone, or in combination, was determined on the MHM over 12 days of storage. Results showed the MHM accurately mimics the ham slice method since no statistical differences were found (p=0.526) in the change of LM cell counts in MHM and slice counts after 12 days of storage at 4°C for treated and untreated hams. The MHM was then used to screen antimicrobial combinations using an on-face design and three center points in a central composite design. The RSM was tested using a cocktail of five LM strains isolated from foodborne disease outbreaks. Three levels of the above mentioned antimicrobials were used in combination for a total of 28 runs performed in triplicate. The change of LM cell counts were determined after 12 days of storage at 4°C. All tested antimicrobials were effective on reducing LM cell counts on ham when added alone. A significant antagonistic interaction (p=0.002) was identified by the RSM between LAG and P100, where this antimicrobial combination caused a 2.2 logCFU/g change of LM cell counts after 12 days of storage. Two interactions, between Ni and EPL (p=0.058), and Ni and P100 (p=0.068), showed possible synergistic effects against LM on the MHM. Other interactions were clearly non-significant, suggesting additive effects. In future work, the developed MHM in combination with RSM can be used as a high-throughput method to analyze novel antimicrobial treatments against LM

Research Note: Preservative effect of compound spices extracts on marinated chicken

“…The lack of fit value was 0.0872 (>0.05), suggesting there is little deviation between the predicted value and the actual value, which belongs to the normal error range, and it is feasible to simulate real 4-factor and 3-level analysis by using this equation. The R 2 value and value of the entire model were 0.9574 and 0.9433, respectively, suggesting that the polynomial model fit the experimental data primely ( Resendiz-Moctezuma et al, 2021 ). Therefore, the best natural preservative ratio for the antibacterial effect of marinated chicken can be selected through this model.…”

Thin Cationic Polymer Coatings against Foodborne Infections

“…Production, storage and distribution of food products require conditions that minimize or terminate development of infections caused, among other things, by bacterial and fungicidal activity [1][2][3][4]. In order to combat pathogenic microorganisms, a wide range of biocidal substances has been suggested that are capable of suppressing their vital activity [5][6][7][8]. Conventional low molecular weight biocides have been applied as bacteriaand-fungi killing agents for years [9][10][11].…”