Effect of HP/T treatments of in-package food on additive migration from conventional and bio-sourced materials

Correspondance: [email protected] audienceMigration was assessed during and after two HP/T treatments intended to perform a pasteurization (800 MPa for 5 min, from 20 to 40 °C) and a sterilization treatment (800 MPa for 5 min, from 90 to 115 °C) and were compared to conventional pasteurization and sterilization respectively. The specific migration of actual packaging additives used as antioxidants and UV absorbers (Irganox 1076, Uvitex OB) was investigated in a number of food-packaging system combining one synthetic common packaging (LLDPE) and a bio-sourced one (PLA) in contact with the four food simulating liquids defined by EC regulations. After standard HP/T processing, migration kinetics was followed during service life of package material using FTIR spectroscopy. LLDPE withstood the HP sterilization whereas it melted during the conventional sterilization. No difference was observed on migration from LLDPE for both treatments. In the case of PLA, migration of Uvitex OB was very low or no detectable for all the studied cases

Mycobacterium tuberculosis Lipolytic Enzymes as Potential Biomarkers for the Diagnosis of Active Tuberculosis

BACKGROUND: New diagnosis tests are urgently needed to address the global tuberculosis (TB) burden and to improve control programs especially in resource-limited settings. An effective in vitro diagnostic of TB based on serological methods would be regarded as an attractive progress because immunoassays are simple, rapid, inexpensive, and may offer the possibility to detect cases missed by standard sputum smear microscopy. However, currently available serology tests for TB are highly variable in sensitivity and specificity. Lipolytic enzymes have recently emerged as key factors in lipid metabolization during dormancy and/or exit of the non-replicating growth phase, a prerequisite step of TB reactivation. The focus of this study was to analyze and compare the potential of four Mycobacterium tuberculosis lipolytic enzymes (LipY, Rv0183, Rv1984c and Rv3452) as new markers in the serodiagnosis of active TB. METHODS: Recombinant proteins were produced and used in optimized ELISA aimed to detect IgG and IgM serum antibodies against the four lipolytic enzymes. The capacity of the assays to identify infection was evaluated in patients with either active TB or latent TB and compared with two distinct control groups consisting of BCG-vaccinated blood donors and hospitalized non-TB individuals. RESULTS: A robust humoral response was detected in patients with active TB whereas antibodies against lipolytic enzymes were infrequently detected in either uninfected groups or in subjects with latent infection. High specifity levels, ranging from 93.9% to 97.5%, were obtained for all four antigens with sensitivity values ranging from 73.4% to 90.5%, with Rv3452 displaying the highest performances. Patients with active TB usually exhibited strong IgG responses but poor IgM responses. CONCLUSION: These results clearly indicate that the lipolytic enzymes tested are strongly immunogenic allowing to distinguish active from latent TB infections. They appear as potent biomarkers providing high sensitivity and specificity levels for the immunodiagnosis of active TB

Bases physico-chimiques et structurales de l'aptitude au fractionnement du grain de blé dur (Triticum Durum Desf.)

MONTPELLIER-SupAgro La Gaillarde (341722306) / SudocSudocFranceF

Worst case prediction of additives migration from polystyrene for food safety purposes: a model update

A reliable prediction of migration levels of plastic additives into food requires a robust estimation of diffusivity. Predictive modelling of diffusivity as recommended by the EU commission is carried out using a semi-empirical equation that relies on two polymer-dependent parameters. These parameters were determined for the polymers most used by packaging industry (LLDPE, HDPE, PP, PET, PS, HIPS) from the diffusivity data available at that time. In the specific case of general purpose polystyrene, the diffusivity data published since then shows that the use of the equation with the original parameters results in systematic underestimation of diffusivity. The goal of this study was therefore, to propose an update of the aforementioned parameters for PS on the basis of up to date diffusivity data, so the equation can be used for a reasoned overestimation of diffusivity

Cinétiques d’oxydation de l’acide ascorbique

National audienc

Contribution of nanoclay to the additive partitioning in polymers

The polymer nanocomposites have become unabatedly popular due to their exceptional properties which results in a plethora of applications including the food packaging. However, safety aspect of these materials is still under debate, specifically in view point of the unknown interactions of nanoparticles with various additives added during the packages processing. For the commonly used polyolefins, the partitioning of additives rather than their diffusivity dictates the extant and extent of these interactions. In this work, the partitioning of various additives between a clay-polymer nanocomposite (CPN) and several food simulants was measured based on a worst-case scenario in viewpoint of the selected polymer and additives. The added value of the CPN in comparison with the pure polymer (LLDPE) was analyzed with regards to their Hansen solubility parameters and log K-log P linearity. Ultimately, an estimation method based on the Flory-Huggins theory was proposed to predict the partition coefficients in CPN

Evaluation of the Food Contact Suitability of Aged Bio-Nanocomposite Materials Dedicated to Food Packaging Applications

Nanocomposite materials based on bio-polyesters (PBSA and PHBV) have been evaluated for their suitability for food contact according to the recommendations defined for non-biodegradable plastic materials, and subsequently, according to accelerated aging treatment. On the basis of the limited number of material/migrant/food simulant combinations studied here, the test for migration, using food simulants, appeared directly applicable to testing such materials which are not considered humidity-sensitive materials. Considering the only compliance criterion that must be met by the materials in contact, the materials submitted to the aging processing are not of safety concern and the incorporation of nanoclays in aged biodegradable materials does not interfere with their inertial properties in a dramatic way. At the molecular scale, the UV irradiation proved to induce an increase in the degree of crystallinity, resulting in a modification of transport properties of both packaging materials. The values of overall migration and specific migration were reduced without decreasing the diffusion coefficients of the target additives. The UV treatment and the addition of nanoparticles, therefore, seem to jointly promote the retention of organic compounds in the materials by increasing their affinity for packaging material

Coupling oxygen transfer and vitamin C oxidation reaction: an experimental and modelling study

International audienc

Effect of nanoclay on the transfer properties of immanent additives in food packages

Polymer nanocomposites and specifically clay-based nanocomposites are emerging in the food packaging area and are promised to have a growing market. While the advantages of the nanoparticles on the gas barrier properties of the nanocomposites are already well-investigated and confirmed, the effect of these nanoparticles on the migration of other non-nano and potentially toxic components of the polymer packaging has still remained unclear. The present study addressed the effect of nanoclay on the migration of various additives from nanoclay/LLDPE nanocomposite packaging by determining the apparent diffusivity of these additives from the samples in contact with four different types of food simulants that distinctively exhibit hydrophilic and lipophilic characters. The results indicated that apart from the tortuosity effect that influence in a low extent the diffusivity of model migrants, the presence of nanoclays modifies the transport properties of materials as a result of their impact on other factors such as crystallinity and swelling capacity. PLS analysis on the influential geometrical and physical properties additionally revealed that the affinity between the food simulant and the polymer has the dominant effect on determining the order of apparent diffusivity as well as the effectiveness of barrier properties of nanoclays to reduce the diffusivity of additives through food packaging. Such statements suggest a benefit provided by nanoparticles incorporation in terms of the human exposure to plastic additives