Gene expression responses of Listeria monocytogenes Scott A exposed to sub-lethal concentrations of natural antimicrobials

Braschi, Giacomo; Serrazanetti, Diana Isabella; Siroli, Lorenzo; Patrignani, Francesca; Angelis, Maria De; Lanciotti, Rosalba

doi:10.1016/j.ijfoodmicro.2018.07.026

Cited by 24 publications

(26 citation statements)

References 49 publications

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“…Among the Gram-positive bacteria, the very high resistance of Staphylococcus aureus to many stress factors and antimicrobials including essential oils and their components is well documented [ 62 , 63 ]. Also the action mechanisms of several essential oil components against many microorganisms, including the target microorganisms taken into consideration in the present research, have been clarified by molecular tools [ 64 , 65 , 66 , 67 ]. The limited antimicrobial effects of the essential oils in the present work is probably due to the masking effect of ethanol and its synergistic effects with low pH values and NaCl of marinade.…”

Section: Discussionmentioning

confidence: 99%

Use of Essential Oils to Increase the Safety and the Quality of Marinated Pork Loin

Siroli

Baldi

Soglia

et al. 2020

Foods

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This study aimed at evaluating the effects of the addition of an oil/beer/lemon marinade solution with or without the inclusion of oregano, rosemary and juniper essential oils on the quality, the technological properties as well as the shelf-life and safety of vacuum-packed pork loin meat. The results obtained suggested that, aside from the addition of essential oils, the marination process allowed to reduce meat pH, thus improving its water holding capacity. Instrumental and sensorial tests showed that the marination also enhanced the tenderness of meat samples, with those marinated with essential oils being the most positively perceived by the panelists. In addition, microbiological data indicated that the marinated samples showed a lower microbial load of the main spoiling microorganisms compared to the control samples, from the 6th to the 13th day of storage, regardless of the addition of essential oils. Marination also allowed to inhibit the pathogens Salmonella enteritidis, Listeria monocytogenes and Staphylococcus aureus, thus increasing the microbiological safety of the product. Overall outcomes suggest that the oil/beer/lemon marinade solution added with essential oils might represent a promising strategy to improve both qualitative and sensory characteristics as well as the safety of meat products.

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Section: Discussionmentioning

confidence: 99%

Use of Essential Oils to Increase the Safety and the Quality of Marinated Pork Loin

Siroli

Baldi

Soglia

et al. 2020

Foods

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“…RT-qPCRs were performed using a Rotor gene 6000 thermal cycler (Corbett Life Science, Mortlake, Australia), according to Braschi et al [21]. Briefly, the RT-PCR reaction mixture (2.5 µL) included 5 ng of cDNA, 6.5 µL of SYBR Premix Ex Taq II (TaKaRa Bio Inc., Shiga, Japan), 0.25 µM of each primer and 4.5 µL of DNAse/RNAse free water (Promega, Wisconsin, USA).…”

Section: Real-time Pcr (Rt-qpcr)mentioning

confidence: 99%

Lactobacillus paracasei A13 and High-Pressure Homogenization Stress Response

et al. 2020

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Sub-lethal high-pressure homogenization treatments applied to Lactobacillus paracasei A13 demonstrated to be a useful strategy to enhance technological and functional properties without detrimental effects on the viability of this strain. Modification of membrane fatty acid composition is reported to be the main regulatory mechanisms adopted by probiotic lactobacilli to counteract high-pressure stress. This work is aimed to clarify and understand the relationship between the modification of membrane fatty acid composition and the expression of genes involved in fatty acid biosynthesis in Lactobacillus paracasei A13, before and after the application of different sub-lethal hyperbaric treatments. Our results showed that Lactobacillus paracasei A13 activated a series of reactions aimed to control and stabilize membrane fluidity in response to high-pressure homogenization treatments. In fact, the production of cyclic fatty acids was counterbalanced by the unsaturation and elongation of fatty acids. The gene expression data indicate an up-regulation of the genes accA, accC, fabD, fabH and fabZ after high-pressure homogenization treatment at 150 and 200 MPa, and of fabK and fabZ after a treatment at 200 MPa suggesting this regulation of the genes involved in fatty acids biosynthesis as an immediate response mechanism adopted by Lactobacillus paracasei A13 to high-pressure homogenization treatments to balance the membrane fluidity. Although further studies should be performed to clarify the modulation of phospholipids and glycoproteins biosynthesis since they play a crucial role in the functional properties of the probiotic strains, this study represents an important step towards understanding the response mechanisms of Lactobacillus paracasei A13 to sub-lethal high-pressure homogenization treatments.

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“…The effect of the presence of EOs and ICs on bacterial growth has been previously studied. According to Braschi, et al [ 37 ], a slower growth rate and a higher lag phase was observed in Listeria monocytogenes as the concentration of carvacrol in the medium increased. Similar results were obtained by Melo, et al [ 38 ] in E. coli and S. aureus against Ocimum gratissimum L. EO: a reduced growth rate and a lag phase delay were observed at higher EO concentrations.…”

Section: Resultsmentioning

confidence: 99%

Genetic Variants and Phenotypic Characteristics of Salmonella Typhimurium-Resistant Mutants after Exposure to Carvacrol

et al. 2020

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The emergence of antimicrobial resistance has raised questions about the safety of essential oils and their individual constituents as food preservatives and as disinfection agents. Further research is required to understand how and under what conditions stable genotypic resistance might occur in food pathogens. Evolution experiments on Salmonella Typhimurium cyclically exposed to sublethal and lethal doses of carvacrol permitted the isolation of SeSCar and SeLCar strains, respectively. Both evolved strains showed a significant increase in carvacrol resistance, assessed by minimum inhibitory and bactericidal concentrations, the study of growth kinetics in the presence of carvacrol, and the evaluation of survival under lethal conditions. Moreover, antibiotic susceptibility tests revealed a development of SeLCar resistance to a wide range of antibiotics. Whole genome sequencing allowed the identification of single nucleotide variations in transcriptional regulators of oxidative stress-response: yfhP in SeSCar and soxR in SeLCar, which could be responsible for the increased resistance by improving the response to carvacrol and preventing its accumulation inside the cell. This study demonstrates the emergence of S. Typhimurium-resistant mutants against carvacrol, which might pose a risk to food safety and should therefore be considered in the design of food preservation strategies, or of cleaning and disinfection treatments.

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Gene expression responses of Listeria monocytogenes Scott A exposed to sub-lethal concentrations of natural antimicrobials

Cited by 24 publications

References 49 publications

Use of Essential Oils to Increase the Safety and the Quality of Marinated Pork Loin

Use of Essential Oils to Increase the Safety and the Quality of Marinated Pork Loin

Lactobacillus paracasei A13 and High-Pressure Homogenization Stress Response

Genetic Variants and Phenotypic Characteristics of Salmonella Typhimurium-Resistant Mutants after Exposure to Carvacrol

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