Synergistic Effects of Lauric Arginate and Peracetic Acid in Reducing Listeria monocytogenes on Fresh Apples

Enhancing the efficacy of peracetic acid against Listeria monocytogenes and Listeria innocua on fresh apples using commercial acidic and alkaline cleaners

Peracetic acid (PAA) is a commonly used antimicrobial in brush-bed spray bar interventions during apple packing. Prior to sanitizer application on the brush-bed, specific fruit cleaners, such as Acidex Duo (AD), EpiClean (EC), Nature's Shield 220-ACL (NS 220), or Nature's Shield 330-ALK (NS 330), are used to remove of soil, debris, and natural wax from the surfaces of apples. This study evaluated the effectiveness of commonly used cleaners in the apple industry to improve the antimicrobial efficacy of PAA against Listeria monocytogenes on apple surfaces during brush-bed spray bar interventions. Granny Smith apples, 48 h post-inoculation, underwent submersion treatment with different cleaners, as well as PAA alone or in combination with the cleaners. A 30-sec treatment of 5.0% AD, 4.2% EC, 10.0% NS 220, and 10.0% NS 330 resulted in 0.65, 0.50, 0.68, and 0.51 log10 CFU/apple reduction of L. monocytogenes on apples, respectively. Incorporating AD, NS 220, and EC significantly enhanced the antimicrobial efficacy of an 80 ppm PAA intervention. The enhancing effects were not impacted whether the cleaner was applied consecutively with PAA (sequentially) or in combination with PAA (simultaneously), nor were they impacted by a post-treatment water rinse. A 30-120 s wash of 80 ppm PAA with AD, EC, and NS 220 at their suggested concentration resulted in 2.46-2.55, 1.87-2.03, and 2.34-2.48 log10 CFU/apple reduction of L. monocytogenes, respectively, compared to 1.39-1.64 log10 CFU/apple in PAA treatment alone. The inclusion of AD or NS 220 in 80 ppm PAA solution resulted in a reduction of 1.51-1.63 log10 CFU/apple of Listeria after 30-60 s brush-bed spray wash. This enhancement in efficacy was significant compared to the treatment with 80 ppm PAA alone, which resulted in a reduction of 0.94-1.03 log10 CFU/apple. This study demonstrated that using certain commercially available cleaners along with PAA can enhance the effectiveness of PAA in reducing L. monocytogenes on fresh apples.

Synergistic effects of benzyl isothiocyanate and resveratrol against Listeria monocytogenes and their application in chicken meat preservation

This study aimed to investigate the synergistic effects of benzyl isothiocyanate (BITC) and resveratrol (RS) on Listeria monocytogenes and their application in chicken meat preservation. BITC combined with RS (BR) significantly enhanced the antimicrobial activity and inhibited the growth of Listeria monocytogenes within 24 h compared to individual treatment, as well as suppressing bacterial swimming and swarming motility, reducing biofilm formation by 56.4%, increasing cell membrane disruption, and inducing intracellular ROS surges. Synergistic effects were associated with the inhibition of biofilm formation, cell membrane destruction, and ROS production. Biofilm removal facilitated the direct antimicrobial action of BR. RS disrupted cell membrane permeability, allowing more BITC into the cells, resulting in increased intracellular antibacterial levels, cell membrane hyperpolarization, and rapid ROS accumulation. Furthermore, BR visibly slowed the microbial growth in chicken flesh stored at 25 °C and 4 °C. Therefore, BR is expected to be a new strategy for food preservation.

Lauric arginate ethyl ester: An update on the antimicrobial potential and application in the food systems

Lauric arginate ethyl ester (LAE), a cationic surfactant with low toxicity, displays excellent antimicrobial activity against a broad range of microorganisms. LAE has been approved as generally recognized as safe (GRAS) for widespread application in certain foods at a maximum concentration of 200 ppm. In this context, extensive research has been carried out on the application of LAE in food preservation for improving the microbiological safety and quality characteristics of various food products. This study aims to present a general review of recent research progress on the antimicrobial efficacy of LAE and its application in the food industry. It covers the physicochemical properties, antimicrobial efficacy of LAE, and the underlying mechanism of its action. This review also summarizes the application of LAE in various foods products as well as its influence on the nutritional and sensory properties of such foods. Additionally, the main factors influencing the antimicrobial efficacy of LAE are reviewed in this work, and combination strategies are provided to enhance the antimicrobial potency of LAE. Finally, the concluding remarks and possible recommendations for the future research are also presented in this review. In summary, LAE has the great potential application in the food industry. Overall, the present review intends to improve the application of LAE in food preservation.

Sustainable bio-based antimicrobials derived from fatty acids: Synthesis, safety, and efficacy

Some conventional sanitizers and antibiotics used in food industry may be of concerns due to generation of toxic byproducts, impact on the environment, and the emergence of antibiotic resistance bacteria. Bio-based antimicrobials can be an alternative to conventional sanitizers since they are produced from renewable resources, and the bacterial resistance to these compounds is of less concern than those of currently used antibiotics. Among the bio-based antimicrobial compounds, those produced via either fermentation or chemical synthesis by covalently or electrovalently attaching specific moieties to the fatty acid have drawn attention in recent years. Disaccharide, arginine, vitamin B1, and phenolics are linked to fatty acids resulting in the production of sophorolipid, lauric arginate ethyl ester, thiamin dilauryl sulfate, and phenolic branched-chain fatty acid, respectively, all of which are reported to exhibit antimicrobial activity by targeting the cell membrane of the bacteria. Also, studies that applied these compounds as food preservatives by combining them with other compounds or treatments have been reviewed regarding extending the shelf life and inactivating foodborne pathogens of foods and food products. In addition, the phenolic branched-chain fatty acids, which are relatively new compounds compared to the others, are highlighted in this review.

Listeria monocytogenes Outbreaks Related to Commercially Produced Caramel Apples: Developments in Sanitation, Product Formulation, and Packaging: A Review

ABSTRACT

Prior to a deadly 2014 listeriosis outbreak, caramel apples were not thought to be vehicles for the foodborne pathogen Listeria monocytogenes. The purpose of this review article is to summarize what has been learned from research prompted by this outbreak. This overview includes descriptions of the two L. monocytogenes infection outbreaks related to prepackaged caramel apples and a brief discussion of apple sanitation, the production processes used to make caramel apples, and research on ways to prevent future outbreaks associated with caramel apples. A qualitative analysis of the literature and interviews with current caramel apple manufacturers were conducted. Sanitation, packaging, and storage procedures used by manufacturers in the past may not effectively inactivate L. monocytogenes from contaminated product. Novel apple sanitation methods and product formulations to control L. monocytogenes on caramel apples have been developed and, in some cases, implemented in commercial production.

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