Selection procedure of bioprotective cultures for their combined use with High Pressure Processing to control spore-forming bacteria in cooked ham

International audienceHigh Pressure Processing (HPP) and biopreservation can contribute to food safety by inactivation of bacterial contaminants. However these treatments are inefficient against bacterial endospores. Moreover, HPP can induce spore germination. The objective of this study was to select lactic acid bacteria strains to be used as bioprotective cultures, to control vegetative cells of spore-forming bacteria in ham after application of HPP. A collection of 63 strains of various origins was screened for their antagonistic activity against spore-forming Bacillus and Clostridium species and their ability to resist to HPP. Some safety requirements should also be considered prior to their introduction into the food chain. Hence, the selection steps included the assessment of biogenic amine production and antibiotic resistance. No strain produced histamine above the threshold detection level of 50 ppm. From the assessment of antibiotic resistance against nine antibiotics, 14 susceptible strains were kept. Antagonistic action of the 14 strains was then assessed by the well diffusion method against pathogenic or spoilage spore-forming species as Bacillus cereus, Clostridium sp. like botulinum, Clostridium frigidicarnis, and Clostridium algidicarnis. One Lactobacillus curvatus strain and one Lactococcus lactis strain were ultimately selected for their widest inhibitory spectrum and their potential production of bacteriocin. A Lactobacillus plantarum strain was included as control. Their resistance to HPP and ability to regrow during chilled storage was then assessed in model ham liquid medium. Treatments of pressure intensities of 400, 500, and 600 MPa, and durations of 1, 3, 6, and 10 min were applied. After treatment, cultures were incubated at 8 °C during 30 days. Inactivation curves were then fitted by using a reparameterized Weibull model whereas growth curves were modelled with a logistic model. Although the two Lactobacillus strains were more resistant than L. lactis to HPP, the latter was the only strain able to regrow following HPP. The absence of biogenic amine production of this strain after growth on diced cube cooked ham was also shown. In conclusion this L. lactis strain could be selected as representing the best candidate for a promising preservative treatment combining biopreservation and HPP to control spore-forming bacteria in cooked ham

Assessing the Acceptability and Feasibility of a Web-Based Screening for Psychoactive Substance Users Among a French Sample of University Students and Workers: Mixed Methods Prospective Study

BackgroundEarly detection in the prevention of addictive behaviors remains a complex question in practice for most first-line health care workers (HCWs). Several prevention measures have successfully included a screening stage followed by a brief intervention in case of risk-related use or referral to an addiction center for problematic use. Whereas early detection is highly recommended by the World Health Organization, it is not usually performed in practice. ObjectiveThe aim of this study was to assess the acceptability and feasibility of a web-based app, called Pulsio Santé, for health service users and first-line prevention HCW and to carry out an exhaustive process of early detection of psychoactive substance use behaviors. MethodsA mixed methods prospective study was conducted in 2 departments: HCWs from the regional occupational health department and from the university department of preventive medicine dedicated to students were invited to participate. Participants 18 years or older who had been seen in 2017 by a HCW from one of the departments were eligible. The study procedure comprised 5 phases: (1) inclusion of the participants after a face-to-face consultation with an HCW; (2) reception of a text message by participants on their smartphone or by email; (3) self-assessment by participants regarding their substance use with the Pulsio Santé app; (4) if participants agreed, transfer of the results to the HCW; and (5) if participants declined, a message to invite them to get in touch with their general practitioner should the assessment detect a risk. Several feasibility and acceptability criteria were assessed by an analysis of a focus group with the HCW that explored 4 themes (usefulness and advantages, problems and limitations, possible improvements, and finally, integration into routine practice). ResultsA total of 1474 people were asked to participate, with 42 HCWs being involved. The percentage of people who agreed to receive a text message or an email, which was considered as the first level of acceptability, was 79.17% (1167/1474). The percentage of participants who clicked on the self-assessment link, considered as the second level of acceptability, was 60.24% (703/1167). The percentage of participants who completed their self-evaluation entirely, which was considered as the first level of feasibility, was 76.24% (536/703). The percentage of participants who shared the results of their evaluation with the HCWs, considered as the second level of feasibility, was 79.48% (426/536). The qualitative study showed that there were obstacles on the side of HCWs in carrying out the recommended interventions for people at risk based on their online screening, such as previous training or adaptations in accordance with specific populations. ConclusionsQuantitative results showed good acceptability and feasibility of the Pulsio Santé app by users and HCWs. There is a need for further studies more directly focused on the limitations highlighted by the qualitative results

Combination of High-Pressure Treatment at 500 MPa and Biopreservation with a Lactococcus lactis Strain for Lowering the Bacterial Growth during Storage of Diced Cooked Ham with Reduced Nitrite Salt

International audienceWe investigated the combined effects of biopreservation and high-pressure treatment on bacterial communities of diced cooked ham prepared with diminished nitrite salt. First, bacterial communities of four commercial brands of diced cooked ham from local supermarkets were characterized and stored frozen. Second, sterile diced cooked ham, prepared with reduced levels of nitrite, was inoculated with two different microbiota collected from the aforementioned commercial samples together with a nisin-producing Lactococcus lactis protective strain able to recover from a 500 MPa high-pressure treatment. Samples were then treated at 500 MPa for 5 min, and bacterial dynamics were monitored during storage at 8 °C. Depending on samples, the ham microbiota was dominated by different Proteobacteria (Pseudomonas, Serratia, Psychrobacter, or Vibrio) or by Firmicutes (Latilactobacillus and Leuconostoc). Applied alone, none of the treatments stabilized during the growth of the ham microbiota. Nevertheless, the combination of biopreservation and high-pressure treatment was efficient in reducing the growth of Proteobacteria spoilage species. However, this effect was dependent on the nature of the initial microbiota, showing that the use of biopreservation and high-pressure treatment, as an alternative to nitrite reduction for ensuring cooked ham microbial safety, merits attention but still requires improvement

Discussion sur le licenciement des officiers demandé dans la motion de M. Robespierre, lors de la séance du 11 juin 1791

La Rochefoucauld-Liancourt François Alexandre, duc de, Cazalès Jacques Antoine de, Roederer Pierre-Louis, Gaultier de Biauzat Jean-François, Anthoine François-Paul, Rewbell Jean François, Dauchy Luc Jacques Edouard, Maury Jean Siffrein, abbé, Robespierre Maximilien. Discussion sur le licenciement des officiers demandé dans la motion de M. Robespierre, lors de la séance du 11 juin 1791. In: Archives Parlementaires de 1787 à 1860 - Première série (1787-1799) Tome XXVII - Du 6 juin au 5 juillet 1791. Paris : Librairie Administrative P. Dupont, 1887. pp. 123-124

Discussion sur le licenciement des officiers demandé dans la motion de M. Robespierre, lors de la séance du 11 juin 1791

La Rochefoucauld-Liancourt François Alexandre, duc de, Cazalès Jacques Antoine de, Roederer Pierre-Louis, Gaultier de Biauzat Jean-François, Anthoine François-Paul, Rewbell Jean François, Dauchy Luc Jacques Edouard, Maury Jean Siffrein, abbé, Robespierre Maximilien. Discussion sur le licenciement des officiers demandé dans la motion de M. Robespierre, lors de la séance du 11 juin 1791. In: Archives Parlementaires de 1787 à 1860 - Première série (1787-1799) Tome XXVII - Du 6 juin au 5 juillet 1791. Paris : Librairie Administrative P. Dupont, 1887. pp. 123-124