Investigation of the Suitability of a Combination of Ethyl-Να-dodecanyl-L-arginat_HCl (LAE) and Starter Culture Bacteria for the Reduction of Bacteria from Fresh Meat of Different Animal Species

Meat can be contaminated with (pathogenic) microorganisms during slaughter, dissection and packaging. Therefore, preservation technologies are frequently used to reduce the risk of (fatal) human infections due to the consumption of meat. In this study, we first investigated, if the application of ethyl-Nα-dodecanyl-L-arginate hydrochloride (LAE) and the starter culture bacteria Staphylococcus carnosus and Lactobacillus sakei, either single or in combination, influences the bacteria number on pork, chicken meat and beef, inoculated with Brochothrix (Br.) thermosphacta (all meat species) or Salmonella (S.) Typhimurium (pork), Campylobacter (C.) jejuni (chicken) and Listeria (L.) monocytogenes (beef), before packaging under modified atmosphere and on days 7 and 14 of storage. To evaluate effects of the treatment on the appearance during storage, additionally, the physicochemical parameters color and myoglobin redox form percentages were analyzed. LAE regularly resulted in a significant reduction of the number of all bacteria species on day 1 of storage, whereas up to day 14 of storage, the preservation effect did not persist in nearly all samples, except in the beef with Br. thermosphacta. However, with the starter culture bacteria on day 1, only L. monocytogenes on beef was significantly reduced. Interestingly, on day 7 of storage, this reducing effect was also found with S. Typhimurium on pork. Br. thermosphacta, which was principally not influenced by the starter culture bacteria. The combinatory treatment mainly resulted in no additional effects, except for the S. Typhimurium and Br. thermosphacta results on pork on day 7 and the Br. thermosphacta results on beef on day 14. The physicochemical parameters were not influenced by the single and combinatory treatment. The results indicate that LAE was mainly responsible for the antimicrobial effects and that a combination with starter culture bacteria should be individually evaluated for the meat species.

The effects of novel alginate-lauric arginate coatings with temperature on bacterial quality, oxidative stability, and organoleptic characteristics of frozen stored chicken drumsticks

Although alginate has been reported to be used as an edible film and coating in food, to the best of our knowledge, this study is the first to investigate the individual effects of coatings, temperatures, storage times, as well as their interactions, on the bacterial quality, deterioration criteria, and sensory attributes of chicken drumsticks. To accomplish this, six groups of chicken drumsticks were treated with different coatings, temperatures, and storage conditions. The groups included 2 % alginate at 25 °C (Alg₂₅) and 50 °C (Alg₅₀), a mixture of 2 % alginate and 2 % LAE at 25 °C (M₂₅) and 50 °C (M₅₀), besides control untreated samples in distilled water at 25 °C (C₂₅) and 50 °C (C₅₀). The chicken drumsticks were stored at -18 °C for 3 months. The results showed that all treated chicken drumsticks induced a significant reduction in all bacterial counts, as well as a significant decrease in pH and thiobarbituric acid values, with an improvement in all sensory attributes, particularly in the M₂₅ and M₅₀ coated samples compared to the C₂₅ and C₅₀. Furthermore, exposing alginate and LAE to a temperature of 50 °C can increase their antimicrobial activity. In conclusion, the innovative combinations of LAE and alginate can be used successfully to decontaminate chicken carcasses in poultry processing plants.

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.

Development of poly(vinyl alcohol)/starch/ethyl lauroyl arginate blend films with enhanced antimicrobial and physical properties for active packaging

Active packaging films have emerged as alternatives to replace petroleum-based packaging materials. In this work, poly(vinyl alcohol) (PVA)/starch/ethyl lauroyl arginate (LAE) films possessing enhanced properties were prepared. Scanning electron microscopy (SEM) showed that PVA and starch were compatible, the concentrations of LAE greatly affected the structural integrity. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction showed that the inclusion of LAE did not significantly affect the intermolecular interactions and crystal structures of the polymer matrix. With an increase of the LAE content, the tensile strength (TS) was slightly decreased due to the altered microstructures, the elongation at break (EB) significantly increased ascribed to the synergistic effect of acetic acid, glycerol and LAE. The values of TS and EB were 17.25 MPa and 586.08%, respectively when LAE was 10%. Active films showed good barrier properties from UV while retaining the transmittance in the visible light region. The films containing 1% of LAE exhibited antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), the inhibition zone of bacterial growth gradually expanded with increasing LAE content. This study demonstrates the potential of using LAE as the antibacterial agent for synthesizing natural-based polymeric films for active packaging applications.

Ethyl Lauroyl Arginate (LAE): Antimicrobial Activity of LAE-Coated Film for the Packaging of Raw Beef and Pork

In this study, the antimicrobial activity of an ethyl lauroyl arginate- (LAE®-) coated film applied to the packaging of raw beef and pork was evaluated. Two different trials were performed for each meat species, aiming to evaluate the functionality of the film in contrasting the development of the natural microflora and of a specific target agent, Escherichia coli ATCC 25922. In the first trial, LAE-coated packaging was applied to test its activity towards the natural meat microflora over a period of 24 days at 6-7°C. The comparison with the control sample series showed a slight initial inhibitory activity on total viable count, followed by a growing trend. In the second trial, the antimicrobial activity of the LAE-coated film was evaluated on raw beef and pork voluntarily inoculated with Escherichia coli: an initial killing effect on E. coli was detected in both pork and beef meat (reduction around 0.7 and 1 log CFU/g, respectively), followed by a stable trend for the following storage period (24 days).

Quantitative approach to assess the compliance to a performance objective (PO) of Campylobacter jejuni in poultry meat in France

Predictive modelling is used in microbiological risk assessment to quantify the growth and inactivation of microorganisms through the use of mathematical models. Campylobacter jejuni is one of the main foodborne pathogens and broiler meat is considered as the most important source of human campylobacteriosis. The purpose of this study was to assess the effects of heating and chilling during the poultry slaughter process on inactivation kinetics of Campylobacter jejuni during chilled storage in order to predict its contamination level prior to preparation and consumption in the consumer's home, and then to assess the compliance to a Performance Objective (PO). Three strains of C. jejuni were submitted to consecutive heat (54 °C for 3 min) and cold (3 °C for 2 h) stresses, mimicking the two main slaughtering steps, i.e. scalding and chilling, by inoculating chicken fillets with three different concentrations (4, 6 and 8 log₁₀ CFU/g). Fillets were then stored at 6 °C during 17 days under the modified atmosphere currently used by food processors (70% O₂/30% CO₂). For all strains, bacterial log reduction was the lowest when inoculated at 8 log₁₀ CFU/g. One strain showed an enhanced resistance during cold storage after application of stressing steps, suggesting an impact of the cell history on further bacterial resistance. Taking strain variability into account, after six days of storage, predictions showed compliance of ready-to-be-cooked chicken meat with a hypothetical PO of 2.55 log₁₀ CFU/g, value set before the meat enters the consumer's home by the ICMSF (International Commission on Microbiological Specifications for Foods). This study opens the path to assess the compliance to a PO of Campylobacter jejuni in poultry meat and more generally provides inputs to refine microbiological risk assessment by taking into account the cell history and more particularly the impact of stressful steps on the subsequent inactivation at consumer's home.

Strategies and novel technologies to control Campylobacter in the poultry chain: A review

Campylobacteriosis is one of the most common bacterial infections worldwide causing economic costs. The high prevalence of Campylobacter spp. in poultry meat is a result of several contamination and cross-contamination sources through the production chain. Moreover, survival mechanisms, such as biofilm formation, viable but nonculturable state, and antimicrobial resistance, enable its persistence during food processing. Therefore, mitigation strategies are necessary in order to avoid and/or inactivate Campylobacter at farm, abattoir, industry, and retail level. In this review, a number of potential strategies and novel technologies that could reduce the prevalence of Campylobacter in poultry meat have been identified and evaluated to provide a useful overview. At farm level for instance, biosecurity, bacteriocins, probiotics, feed and water additives, bacteriophages, and vaccination could potentially reduce colonization in chicken flocks. However, current technologies used in the chicken slaughter and processing industry may be less effective against this foodborne pathogen. Novel technologies and strategies such as cold plasma, ultraviolet light, high-intensity light pulses, pulsed electric fields, antimicrobials, and modified atmosphere packaging are discussed in this review for reducing Campylobacter contamination. Although these measures have achieved promising results, most have not been integrated within processing operations due to a lack of knowledge or an unwillingness to implement these into existing processing systems. Furthermore, a combination of existing and novel strategies might be required to decrease the prevalence of this pathogen in poultry meat and enhance food safety. Therefore, further research will be essential to assess the effectiveness of all these strategies.

Antibiotic-Resistant Salmonella in the Food Supply and the Potential Role of Antibiotic Alternatives for Control

Salmonella enterica is one of the most ubiquitous enteropathogenic bacterial species on earth, and comprises more than 2500 serovars. Widely known for causing non-typhoidal foodborne infections (95%), and enteric (typhoid) fever in humans, Salmonella colonizes almost all warm- and cold-blooded animals, in addition to its extra-animal environmental strongholds. The last few decades have witnessed the emergence of highly virulent and antibiotic-resistant Salmonella, causing greater morbidity and mortality in humans. The emergence of several Salmonella serotypes resistant to multiple antibiotics in food animals underscores a significant food safety hazard. In this review, we discuss the various antibiotic-resistant Salmonella serotypes in food animals and the food supply, factors that contributed to their emergence, their antibiotic resistance mechanisms, the public health implications of their spread through the food supply, and the potential antibiotic alternatives for controlling them.

Application of Antimicrobial Agents via Commercial Spray Cabinet To Inactivate Salmonella on Skinless Chicken Meat

Salmonella enterica subsp. enterica serovar Typhimurium is a food safety concern for raw poultry products. New and innovative application methods of antimicrobials for the reduction of Salmonella in poultry and poultry products are essential. The aim of this study was to determine the efficacy of three antimicrobial compounds against Salmonella on raw chicken meat when applied individually and in combination using a commercial spray cabinet. Raw chicken thigh meat inoculated with 5 log CFU/g Salmonella Typhimurium ATCC 53647 was passed through a spray cabinet while being sprayed with 5% lauric arginate (LAE), 0.8% vinegar solution (VS), near-neutral electrolyzed water, or deionized water. The following three experiments were carried out: (i) exposure times of 0, 15, 30, 45, and 60 s, (ii) storage at 4°C for 0, 1, 2, and 3 days after a 60-s exposure, and (iii) a combination of treatment with LAE and VS followed by storage at 4°C for 0, 1, 2, and 3 days. Analysis of variance and the Tukey test were used to determine mean significant differences (P < 0.05). The experiment was carried out in duplicate for each replicate (n = 3 × 2). In comparing individual antimicrobials, the 60-s treatment time resulted in the greatest reduction of Salmonella Typhimurium, with LAE achieving the greatest reduction (2.07 log), followed by VS, near-neutral electrolyzed water, and deionized water (0.63, 0.56, and 0.53 log, respectively). After 3 days of storage, LAE significantly (P < 0.05) reduced Salmonella Typhimurium, by 1.28 log. The combination of VS and then LAE resulted in a significantly (P < 0.05) greater reduction than using LAE followed by VS (1.61 and 0.93 log, respectively). The results of this study suggest that LAE is a viable compound to reduce Salmonella Typhimurium on raw chicken meat and that the order of application of antimicrobial agents plays a vital role.

Reducing Campylobacter jejuni colonization of poultry via vaccination

Campylobacter jejuni is a leading bacterial cause of human gastrointestinal disease worldwide. While C. jejuni is a commensal organism in chickens, case-studies have demonstrated a link between infection with C. jejuni and the consumption of foods that have been cross-contaminated with raw or undercooked poultry. We hypothesized that vaccination of chickens with C. jejuni surface-exposed colonization proteins (SECPs) would reduce the ability of C. jejuni to colonize chickens, thereby reducing the contamination of poultry products at the retail level and potentially providing a safer food product for consumers. To test our hypothesis, we injected chickens with recombinant C. jejuni peptides from CadF, FlaA, FlpA, CmeC, and a CadF-FlaA-FlpA fusion protein. Seven days following challenge, chickens were necropsied and cecal contents were serially diluted and plated to determine the number of C. jejuni per gram of material. The sera from the chickens were also analyzed to determine the concentration and specificity of antibodies reactive against the C. jejuni SECPs. Vaccination of chickens with the CadF, FlaA, and FlpA peptides resulted in a reduction in the number of C. jejuni in the ceca compared to the non-vaccinated C. jejuni-challenged group. The greatest reduction in C. jejuni colonization was observed in chickens injected with the FlaA, FlpA, or CadF-FlaA-FlpA fusion proteins. Vaccination of chickens with different SECPs resulted in the production of C. jejuni-specific IgY antibodies. In summary, we show that the vaccination of poultry with individual C. jejuni SECPs or a combination of SECPs provides protection of chickens from C. jejuni colonization.