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Understanding the bacterial behavior in response to sublethal stresses is crucial for the optimization of antimicrobial treatments, particularly in food processing. However, the data regarding the effect of sublethal concentrations of essential oils (EOs) on microbial cells are still scarce. In this study, we evaluated the response of Listeria monocytogenes ATCC 7644 to the sublethal concentration of 1.25 μL/mL Origanum vulgare L. EO at 30 °C for 1 h, by means of Phenotype Microarray, modelling the kinetic data obtained by inoculating the control and treated cells into GEN III microplates (Biolog Inc.) for 96 h after EO removal. The results showed important differences regarding the growth dynamics in the presence of carbohydrates and environmental conditions often encountered in food products and that normally sustain the growth of the pathogen (i.e. pH 6.0, pH 5.0, NaCl 1–8%, presence of lactic acid and sodium lactate). In detail, the lag phase of the treated cells was extended, the growth rate was slowed down and the maximum concentration was often significantly reduced. Interestingly, the susceptibility to antimicrobials such as vancomycin, lincomycin and rifamycin was restored after EO application and removal, suggesting a potential role in combating antibiotic resistance. Confocal laser scanner microscopy showed a diffuse aggregation of the treated cells, as a response to the stress encountered. In conclusion, a single exposure to a sublethal concentration of O. vulgare EO causes a stressing effect that persists after its removal. This outcome should be better investigated for potential applications both in food production, to combine low EO concentrations with other hurdles to guarantee food safety, and in medicine, to restore the sensitivity to antibiotics. • L. monocytogenes was exposed to a sublethal quantity of O. vulgare essential oil (OEO). • The single exposure to OEO changed growth dynamics in treated cells. • Restoration of sensitivity to vancomycin, lincomycin, rifamycin was observed. • The stress caused by OEO determined cells aggregation. • Sublethal OEO concentration causes a stressing effect persisting after OEO removal. [ABSTRACT FROM AUTHOR]

Among pathogens, L. monocytogenes has the capability to persist on Food Processing Environment (FPE), first of all posing safety issues, then economic impact on productivity. The aim of this work was to determine the influence of biofilm forming-ability and molecular features on the persistence of 19 Listeria monocytogenes isolates obtained from FPE, raw and processed products of a cold-smoked salmon processing plant. To verify the phenotypic and genomic correlations among the isolates, different analyses were employed: serotyping, Clonal Complex (CC), core genome Multi-Locus Sequence Typing (cgMLST) and Single Nucleotide Polymorphisms (SNPs) clustering, and evaluation of the presence of virulence- and persistence-associated genes. From our results, the biofilm formation was significantly higher (* P < 0.05) at 37 °C, compared to 30 and 12 °C, suggesting a temperature-dependent behaviour. Moreover, the biofilm-forming ability showed a strain-specific trend, not correlated with CC or with strains persistence. Instead, the presence of internalin (inL) , Stress Survival Islet (SSI) and resistance to erythromycin (ermC) genes was correlated with the ability to produce biofilms. Our data demonstrate that the genetic profile influences the adhesion capacity and persistence of L. monocytogenes in food processing plants and could be the result of environmental adaptation in response to the external selective pressure. • 19 L. monocytogenes isolates from a smoked salmon processing plant were analysed. • Persistence was related to biofilm-forming ability and genetic pattern. • Biofilm production is not the only requisite for isolates persistence. • inL, SSi and ermC correlated with ability to form biofilm. • Virulence and stress tolerance genes can determine persistence in L. monocytogenes. [ABSTRACT FROM AUTHOR]

Ready-to-eat (RTE) vegetables, including fresh-cut ones, are exposed to the risk of the foodborne pathogen Listeria monocytogenes. Nowadays, fresh-cut products are widely consumed because of their convenience. Nevertheless, effective washing treatments are required for their preparation, to maintain freshness and microbiological safety. Currently, natural substances are increasingly demanded as alternatives to traditional synthetic washing agents. Therefore, this study investigates the application of Thymbra capitata hydrolate as washing solution for rocket salad (Eruca sativa) stored at 4 °C for 48 h, to evaluate a potential application both during the production process of fresh-cut vegetables, and also at the domestic level. The hydrolate applied at a concentration of 500 μL/mL for 5 min allowed to reduce L. monocytogenes load of about 1 log CFU/g at each time of analysis, and to determine a significant reduction of microbial groups normally found on rocket salad, particularly total mesophilic and psychrotrophic counts. The treatment showed no negative effects on pH, a w , and colour of the rocket salad. At a sensory level, the differences among control and treated samples were minimally perceived only on the first day of analysis but disappeared over time. Therefore, this alternative washing treatment revealed to counteract L. monocytogenes growth and to help maintaining the quality of rocket salad. Hence, it could be optimized for a concrete application, also considering the enhancement of the antilisterial activity, the sustainability and low cost of the hydrolate, which represents a by-product from the production of essential oils. • Washing rocket salad with T. capitata hydrolate reduced L. monocytogenes count. • The treatment also reduced microbial groups normally found on rocket salad. • pH, a w , and colour were similar for control and treated samples. • Sensorial perception of the hydrolate disappeared over time. • The hydrolate had antibacterial effect not affecting rocket salad acceptability. [ABSTRACT FROM AUTHOR]

Abstract: Background and purpose: Oropharyngeal mycosis (OPM) is a complication of radiotherapy (RT) treatments for head and neck (H&N) cancer, worsening mucositis and dysphagia, causing treatment interruptions and increasing overall treatment time. Prophylaxis with antifungals is expensive. Better patient selection through the analysis of prognostic factors should improve treatment efficacy and reduce costs. Materials and methods: A multicentre, prospective, controlled longitudinal study, with ethics committee approval, examined H&N cancer patients who were candidates for curative treatments with radio-chemotherapy. Patients were divided in groups according to OPM appearance: before the starting of RT (cases), during RT (new cases) and never (no cases). Results: Of 410 evaluable patients, 20 were existing cases, 201 new cases and 189 did not report OPM. In our study OPM appears in 42.4% of people >70years and in 58.2% of younger individuals (p =0.0042), and in 68.6% of women versus 50.8% of men (p =0.0069). Mucositis and dysphagia were higher and salivation reduced among people with OPM (p <0.0000). Patients with OPM had longer hospitalization (p =0.0002) and longer (>12days) treatment interruptions (p =0.0288). Conclusions: Patients with OPM had higher toxicity and a greater number of long treatment interruptions. Analyses of prognostic factors can help clinicians understand OPM distribution and select patients with the highest probability of OPM for antifungal prophylaxis. [Copyright &y& Elsevier]