Publications by authors named "Monique Lacroix"

108 Publications

Protein quality of a probiotic beverage enriched with pea and rice protein.

J Food Sci 2021 Jul 15. Epub 2021 Jul 15.

Research Laboratories in Sciences, Applied to Food, Canadian Irradiation Centre, INRS Armand-Frappier, Health and Biotechnology Centre, Institute of Nutrition and Functional Foods, Laval, Québec, Canada.

The aim of this study was to evaluate the effect of the fermentation of a probiotic beverage enriched with pea and rice proteins (PRF) on its protein quality. The protein quality was determined as the protein efficiency ratio (PER), net protein ratio (NPR), and the apparent (AD) and the true digestibility (TD) evaluated in vivo. The probiotic beverage was incorporated to a rat diet at a final concentration of 10% protein, for the evaluation of the PER, the NPR, the AD, and the TD. The protein digestibility amino acid score was also calculated. Results showed that the fermentation of beverage enriched with PRF had no effect on the TD but significantly increased the PER and the NPR (P ≤ 0.05) from 1.88 to 2.32 and from 1.66 to 2.30, respectively. Thus, the fermentation increased the protein quality of the PRF probiotic beverage. In addition, to determine if the beverage constitute in a good carrier matrix for the probiotics, the level of alive probiotics in the feces was evaluated and showed a concentration of 7.4 log CFU/g. PRACTICAL APPLICATION: Plant proteins are often of lower quality compared to animal proteins. Lactic acid fermentation of pea and rice protein has allowed to reach the same protein quality as casein. A plant-based fermented beverage with high protein quality and enriched with probiotics was developed.
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http://dx.doi.org/10.1111/1750-3841.15838DOI Listing
July 2021

Development of antimicrobial films based on poly(lactic acid) incorporated with Thymus vulgaris essential oil and ethanolic extract of Mediterranean propolis.

Int J Biol Macromol 2021 Jun 30;185:535-542. Epub 2021 Jun 30.

Research Laboratory in Sciences Applied to Food, Canadian Irradiation Center (CC), INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, QC H7V 1B7, Canada. Electronic address:

Antimicrobial films based on polylactic acid (PLA) were developed by incorporating Thymus vulgaris essential oil (TV-EOs) with different concentrations of ethanolic extract of Mediterranean propolis (EEP) (5 wt% and 10 wt% based on PLA). The antimicrobial activities of EEP were performed by the agar disc diffusion method. The EEP exhibited high antimicrobial properties with inhibition zone diameter of 12.1 and 11.58 mm against Staphylococcus aureus and Penicillium sp., respectively. The addition of TV-EOs to films containing 5 and 10 wt% of EEP decrease the elastic modulus from 1292 MPa to 1084 MPa and 911.1 MPa to 794 MPa compared with films containing 5 and 10% of EEP alone, respectively. However, the elongation at break increased by 64% after the addition of TV-EOs to the film containing 10 wt% of EEP. Thermal stability of films improvement by the addition of TV-EOs and EEP. Antimicrobial activity of the films showed that films containing 10 wt% EEP inhibited the growth of Candida albicans and the combination of EEP and TV-EOs in the PLA matrix showed a synergistic effect against Escherichia coli. The developed PLA-based films with antimicrobial activity have a potential application in food packaging to increase the shelf life of packaged food.
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http://dx.doi.org/10.1016/j.ijbiomac.2021.06.194DOI Listing
June 2021

A rapid way of formulation development revealing potential synergic effects on numerous antimicrobial combinations against foodborne pathogens.

Microb Pathog 2021 Jun 12;158:105047. Epub 2021 Jun 12.

Research Laboratories in Sciences Applied to Food, Canadian Irradiation Center, INRS-Institut Armand-Frappier, Institute of Nutraceutical and Functional, Laval, Quebec, Canada. Electronic address:

The interactions between various essential oils (EOs) were evaluated for the development of antimicrobial formulations. A full factorial design was applied for testing eight EOs (Mustard, Thyme, Garlic, Oregano, Chinese cinnamon, Cinnamon bark, Red bergamot, Winter savory) against nine bacteria (E.coli O157:H7 RM1239, E.coli O157:H7 RM 1931, E.coli O157:H7 RM 1933, E.coli O157:H7 RM 1934, E.coli O157:H7 380-94, Listeria monocytogenes LM 1045, Listeria innocua ATCC 51742, Salmonella Typhimurium SL 1344, Salmonella enterica Newport ATCC 6962) and two molds (Penicillium chrysogenum ATCC 10106, Aspergillus niger ATCC 1015). Results showed that combinations of Thyme + Oregano, Oregano + Cinnamon bark, Chinese cinnamon + Cinnamon bark have shown high interactions in Factorial design and validated to be mostly additive effects against tested bacteria. The combination of Mustard + Thyme, Mustard + Garlic, and Thyme + Garlic EOs showed high interactions and also all additive effects against tested molds. The corresponding results of Factorial design and checkerboard render the designation to demonstrate the highly efficient formulations and interactions rapidly among abundant mixtures.
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http://dx.doi.org/10.1016/j.micpath.2021.105047DOI Listing
June 2021

Chemical composition, antimicrobial, antioxidant and cytotoxic activity of the essential oil from the leaves of Stachys pilifera Benth.

FEMS Microbiol Lett 2021 05;368(9)

Research Laboratories in Sciences Applied to Food, Canadian Irradiation Center, INRS-Armand Frappier, Health and Biotechnology Center, Institute of Nutrition and Functional Foods, Laval, QC, Canada.

Stachys pilifera Benth is an endemic species of Stachys family found in Iran with a wide application as an herbal tea. The objective of this research was to evaluate the antimicrobial, antioxidant and cytotoxic activity of the essential oil from the aerial parts of S. pilifera. Essential oil (EO) composition analysis showed that cis-Chrysanthenyl acetate (24.9%), viridiflorol (18.3%), trans-Caryophyllene (9.8%), caryophyllene oxide (4.6%), α-terpineol (3.3%) and linalool (3.1%) were the most abundant components. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the EO showed a higher antimicrobial activity against Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) than Gram-negative organisms (Escherichia coli, Shigella sonnei, Pseudomonas aeruginosa and Salmonella enterica subsp. Enterica). The antioxidant activity of EO was studied using DPPH, FRAP and β-carotene/linoleic acid assays. IC50 for the DPPH, FRAP and β-carotene/linoleic acid tests were 23.2, 28.7 and 16.1 µg/mL, respectively, that it was higher than the results for BHT (P ≤ 0.05). The cytotoxic activity of the EO was evaluated using HT29 and HUVEC cells and it was observed that by increasing in EO concentration from 0.026 to 19.4 ug/mL, the viability of the cells for HT29 and HUVEC reduced to 6.8 and 7.1%, respectively. The results from this study suggest the possibility to use the essential oils from S. pilifera Benth as a natural preservative in processed or packaged food due to its high antibacterial, antioxidant and cytotoxic activities.
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http://dx.doi.org/10.1093/femsle/fnab050DOI Listing
May 2021

Analysis of the Ligand Recognition Specificities of Human Ficolins Using Surface Plasmon Resonance.

Methods Mol Biol 2021 ;2227:205-226

Univ. Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France.

Ficolins are innate immune recognition proteins involved in activation of the lectin complement pathway. These oligomeric lectin-like proteins are assembled from subunits consisting of a collagen-like triple helix and a trimeric fibrinogen-like recognition domain. In humans, three ficolins coexist: they differ in their ligand binding specificities, but share the capacity to associate with proteases through their collagen-like stalks and trigger complement activation. We describe methods to decipher the recognition specificities of ficolins, based on surface plasmon resonance, an optical technique allowing real-time and label-free monitoring of biomolecular interactions. This technique was mainly used to characterize and compare binding of the three recombinant full-length ficolins and of their isolated recognition domains to various immobilized BSA-glycoconjugates, acetylated BSA or biotinylated heparin. The avidity phenomenon that enhances the apparent affinity of interactions between oligomeric lectin-like proteins and the multivalent ligands is also discussed.
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http://dx.doi.org/10.1007/978-1-0716-1016-9_19DOI Listing
June 2021

Potential role of probiotics in reducing Clostridioides difficile virulence: Interference with quorum sensing systems.

Microb Pathog 2021 Apr 18;153:104798. Epub 2021 Feb 18.

Institut National de Recherche Scientifique-Armand-Frappier, Health and Biotechnology Centre, Laval, QC, Canada. Electronic address:

Opportunistic pathogenic bacteria may cause disease after the normally protective microbiome is disrupted (typically by antibiotic exposure). Clostridioides difficile is one such pathogen having a severe impact on healthcare facilities and increasing costs of medical care. The search for new therapeutic strategies that are not reliant on additional antibiotic exposures are currently being explored. One such strategy is to disrupt the production of C. difficile virulence factors by interfering with quorum sensing (QS) systems. QS has been well studied in other bacteria, but our understanding in C. difficile is not so well understood. Some probiotic strains or combinations of strains have been shown to be effective in the treatment or primary prevention of C. difficile infections and may possess multiple mechanisms of action. One mechanism of probiotics might be the inhibition of QS, but their role has not been clearly defined yet. A literature search was conducted using standard databases (PubMed, Google Scholar) from database inception to August 2020. The objective of this paper is to update our understanding of how QS leads to toxin production by C. difficile, which is important in pathogenesis, and how QS inhibitors or probiotics may disrupt this pathway. We found two main QS systems for C. difficile (Agr and Lux systems) that are involved in C. difficile pathogenesis by regulating toxin production, motility and adherence. Probiotics and other QS inhibitors targeting QS systems may represent important new directions of therapy and prevention of CDI.
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http://dx.doi.org/10.1016/j.micpath.2021.104798DOI Listing
April 2021

The Acid-Dependent and Independent Effects of Lactobacillus acidophilus CL1285, Lacticaseibacillus casei LBC80R, and Lacticaseibacillus rhamnosus CLR2 on Clostridioides difficile R20291.

Probiotics Antimicrob Proteins 2021 Jan 25. Epub 2021 Jan 25.

Institut National de Recherche Scientifique-Centre Armand-Frappier Santé Biotechnologie, 531 boulevard des Prairies, Québec, H7V 1B7, Laval, Canada.

Clostridioides difficile infections (CDI) result from antibiotic use and cause severe diarrhea which is life threatening and costly. A specific probiotic containing Lactobacillus acidophilus CL1285, Lacticaseibacillus casei LBC80R, and Lacticaseibacillus rhamnosus CLR2 has demonstrated a strong inhibitory effect on the growth of several nosocomial C. difficile strains by production of antimicrobial metabolites during fermentation. Though there are several lactobacilli shown to inhibit C. difficile growth by processes relying on acidification, this probiotic has demonstrated potency for CDI prevention among hospitalized patients. Here, we describe the acid-dependent and independent mechanisms by which these strains impair the cytotoxicity of a hypervirulent strain, C. difficile R20291 (CD). These bacteria were co-cultured in a series of experiments under anaerobic conditions in glucose-rich and no-sugar medium to inhibit or stimulate CD toxin production, respectively. In glucose-rich medium, there was low CD toxin production, but sufficient amounts to cause cytotoxic damage to human fibroblast cells. In co-culture, there was acidification by the lactobacilli resulting in growth inhibition as well as ≥ 99% reduced toxin A and B production and no observable cytotoxicity. In the absence of glucose, CD produced much more toxin. In co-culture, the lactobacilli did not acidify the medium and CD growth was unaffected; yet, the amount of detected toxin A and B was decreased by 20% and 41%, respectively. Despite the high concentration of toxin, cells exposed to the supernatant from the co-culture were able to survive. These results suggest that in addition to known acid-dependent effects, the combination of L. acidophilus CL1285, L. casei LBC80R, and L. rhamnosus CLR2 can interfere with CD pathogenesis without acidification: (1) reduced toxin A and B production and (2) toxin neutralization. This might explain the strain specificity of this probiotic in potently preventing C. difficile-associated diarrhea in antibiotic-treated patients compared with other probiotic formulae.
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http://dx.doi.org/10.1007/s12602-020-09729-5DOI Listing
January 2021

Influence of cellulose nanocrystals gellan gum-based coating on color and respiration rate of Agaricus bisporus mushrooms.

J Food Sci 2021 Feb 12;86(2):420-425. Epub 2021 Jan 12.

Research Laboratories in Sciences Applied to Food, Canadian Irradiation Centre (CIC), INRS Armand-Frappier, Health and Biotechnology Centre, University of Quebec, 531 Boulevard des Prairies, Laval, QC, H7V 1B7, Canada.

The edible coating has been used for covering fruits and vegetables, bringing surface protection, and extending product shelf-life. Due to the outstanding properties, nanomaterials have become a part of the packaging/coating new generation, demonstrating improvements in the barrier capacity of materials starting from construction products to the food industry. In the food industry, on the other hand, Agaricus bisporus mushrooms have a limited shelf-life from 1 to 3 days because of their high respiration rate and enzymatic browning. With the aim to reduce these two parameters and prevent rapid senescence, the objective of this study was to incorporate a natural source of nanomaterials (cellulose nanocrystals (CNCs) into a gellan gum-based coating and sprayed the surface of the mushrooms with the coating material. To evaluate the effect of CNCs, oxygen consumption, carbon dioxide production rate, and color change were recorded during the mushroom storage at 4 ± 1 °C. Results showed that all coatings were able to decrease total color change (ΔE) of mushrooms from 12 to 8 at day 10 when the coating was applied in all samples compared to control. In addition, significant differences were observed in the respiration rate when CNCs were added to the mushrooms. Oxygen consumption results exhibited a 44 mL O /kg · day production at day 5 with 20% CNCs compared to 269 mL O /kg · day observed in noncoated samples. This trend was similarly observed in the carbon dioxide production rate. PRACTICAL APPLICATION: With this research, it was remarkable to see the presence of CNCs in the coating solution reduced the respiration rate and increased the shelf-life of mushrooms. Similar applications can be industrially scaled-up to protect fruits and vegetables by CNCs-based coating or packaging materials. A variety of sustainable materials are available nowadays that serve as packaging matrix, and scientists are working on expanding the compatibility of these nanomaterials. In addition, it has been studied that CNCs enhance the degradation of polymers, an effort that many companies are making to reduce the environmental impact in their products.
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http://dx.doi.org/10.1111/1750-3841.15580DOI Listing
February 2021

In vivo assessment and characterization of lactic acid bacteria with probiotic profile isolated from human milk powder.

Nutr Hosp 2021 Feb;38(1):152-160

Laboratorio de Microbiología Industrial Área Investigación. Departamento de Farmacología. Centro Universitario de Ciencias Exactas e Ingenierías. Universidad de Guadalajara.

Introduction: Introduction: breast milk (MH) contains nutrients and bioactive compounds for child development, including probiotic bacteria, which contribute to intestinal maturation. This benefit accompanies the individual until adulthood. There are new methods such as spray drying that give this compound a good conservation without loss of microbiota. Objective: the aim of this study was to analyze the viability of lactic acid bacteria isolated from human milk with probiotic potential after the spray drying process, as well as to evaluate the possible adhesion in the colon of mice of the Balb/C strain after feeding them powdered human milk and a commercial formula milk. Method: we isolated and identified the presence of lactic acid bacteria with possible probiotic potential in powdered human milk using the MALDI-TOF MS technique. Powdered human milk and a commercial formula milk were fed to mice of the Bald/C strain for 14 weeks. Glucose level and weight were measured in the mice. The feces were collected to verify the presence of lactic bacteria. The mice were sacrificed and their intestines were weighed, isolating the lactic acid bacteria both from the intestines and from the feces. The strains isolated from mice fed human milk were evaluated for their probiotic potential, analyzing their ability to inhibit pathogens, resistance to pH, temperature, adhesion, and hydrophobicity. Results: the presence of Lactobacillus fermentum LH01, Lactobacillus rhamnosus LH02, Lactobacullis reuteri LH03, and Lactobacillus plantarum LH05 in powdered human milk was identified. All strains showed a possible probiotic profile due to the ability of bacteria to resist low pH, bile salts, and exposure to gastric enzymes, as well as their hydrophobicity and self-aggregation capacity, and their failure to show hemagglutination or hemolysis activity in a culture medium rich in erythrocytes. We observed that the consumption of powdered human milk prevented weight gain and constipation in mice. Conclusions: after spray drying, strains with possible probiotic potential may be preserved in human milk. The consumption of powdered human milk with probiotic bacteria prevents constipation and weight gain in mice, when compared to those fed a commercial formula milk.
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http://dx.doi.org/10.20960/nh.03335DOI Listing
February 2021

A fluorescence immunoassay for a rapid detection of Listeria monocytogenes on working surfaces.

Sci Rep 2020 12 10;10(1):21729. Epub 2020 Dec 10.

INRS Armand-Frappier Health and Biotechnology Centre, Research Laboratories in Sciences, Applied to Food, Institute of Nutraceutical and Functional Foods (INAF), 531 Boulevard des Prairies, Laval, QC, H7V 1B7, Canada.

Listeria monocytogenes is a foodborne pathogen responsible for human listeriosis. The increasing incidence of listeriosis induced governments and food manufacturing enterprises to act to diminish the problem. Several methods for the detection of Listeria monocytogenes in food industries were developed. However, they are time-consuming and require the use of specialized equipment. To reduce the detection time of Listeria monocytogenes in food, in this work we developed a fluorescence sandwich immunoassay based on the use of an innovative chitosan-cellulose nanocrystal (CNC) membrane that improves the antigen capture during bacterial growth. The combined use of CNC film for the capture of p60 protein-specific antigen together with the use of fluorescence detection reduced the time of analysis from 24 to 12 h with a limit of detection (LOD) of the assay of 10 CFU/mL (2 Log). In addition, the use of monoclonal anti-PepD covalently immobilized to a CNC membrane assured a high specificity of the assay. Interestingly, the obtained results show no cross-reactivity with the five most diffused pathogen bacteria strains tested.
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http://dx.doi.org/10.1038/s41598-020-77747-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7729958PMC
December 2020

Norovirus elimination on the surface of fresh foods.

Crit Rev Food Sci Nutr 2020 Nov 28:1-16. Epub 2020 Nov 28.

Research Laboratories in Sciences, Applied to Food, Canadian Irradiation Centre, Nutraceuticals and Functional Foods, Laval, Québec, Canada.

Fresh foods like fruits, vegetables and shellfish are potential sources for viral infections such as human norovirus (NoV). Chemical treatment like chlorination is a well-known process for food pathogens and virus elimination. However, with the increase of the consumer demand for less toxic treatment, the use of natural antimicrobials like essential oils from spice or plants, fruit extracts, and cold pasteurization treatments (fermentation, irradiation, ozonation and high pressure) could be considered. The aim of this review is to discuss these technologies and their efficacy to eliminate NoV on the surface of fresh food.
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http://dx.doi.org/10.1080/10408398.2020.1848784DOI Listing
November 2020

Enteropathogenic Potential of Isolates from Soil, Animals, Food and Biopesticides.

Foods 2020 Oct 17;9(10). Epub 2020 Oct 17.

Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Schönleutnerstr. 8, 85764 Oberschleißheim, Germany.

Despite its benefits as biological insecticide, bears enterotoxins, which can be responsible for a diarrhoeal type of food poisoning. Thus, all 24 isolates from foodstuffs, animals, soil and commercially used biopesticides tested in this study showed the genetic prerequisites necessary to provoke the disease. Moreover, though highly strain-specific, various isolates were able to germinate and also to actively move, which are further requirements for the onset of the disease. Most importantly, all isolates could grow under simulated intestinal conditions and produce significant amounts of enterotoxins. Cytotoxicity assays classified 14 isolates as highly, eight as medium and only two as low toxic. Additionally, growth inhibition by essential oils (EOs) was investigated as preventive measure against putatively enteropathogenic . Cinnamon Chinese cassia showed the highest antimicrobial activity, followed by citral, oregano and winter savory. In all tests, high strain-specific variations appeared and must be taken into account when evaluating the hazardous potential of and using EOs as antimicrobials. Altogether, the present study shows a non-negligible pathogenic potential of , independently from the origin of isolation. Generally, biopesticide strains were indistinguishable from other isolates. Thus, the use of these pesticides might indeed increase the risk for consumers' health. Until complete information about the safety of the applied strains and formulations is available, consumers or manufacturers might benefit from the antimicrobial activity of EOs to reduce the level of contamination.
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http://dx.doi.org/10.3390/foods9101484DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7603059PMC
October 2020

Radiosensitivity of Feline Calicivirus F9 on Iceberg Lettuce Surface after Combined Treatments with γ-Radiation.

J Food Prot 2020 Dec;83(12):2134-2146

INRS, Armand-Frappier, Health and Biotechnology Centre, Research Laboratories in Sciences Applied to Food, Canadian Irradiation Centre, 531 Boulevard des Prairies, Laval, Québec, Canada H7V 1B7.

Abstract: The surface of iceberg lettuce (Lactuca sativa L.) is favorable to the survival of pathogens such as bacteria, parasites, and viruses such as norovirus. The present study was conducted to investigate the antiviral properties of treatment with cranberry juice (CJ), ozone (O3), and γ-radiation alone or in combination against feline calicivirus (FCV) F9 present on the surface of iceberg lettuce. The lettuce leaves were inoculated with virus suspensions at ∼6 log TCID50 (50% tissue culture infective dose)/mL and treated with CJ, O3, and γ-radiation alone and in combination during storage at 4°C. The D10-values of 1.21 kGy, 2.23% CJ, and 14.93 ppm of O3 were obtained when samples were treated with various radiation doses, CJ, and O3, respectively. Relative radiosensitization of FCV-F9 virus on lettuce was 1.20, 1.50, 1.09, and 1.00 after combined CJ treatments of 0.1, 0.25, 0.50, and 1.50%, respectively. Optimum treatments were 5 ppm for 7.5 min for O3, 0.25% CJ, and γ-radiation at 1.5 kGy when each treatment was used alone. The combination of the three treatments produced the highest reduction of 2.15 log TCID50/mL (from initial inoculation of ∼7 log TCID50/mL) during 10 days of storage at 4°C. Antibacterial properties of treatments and physicochemical quality of lettuce were investigated during 13 days of storage at 4°C. The treatment of lettuce with γ-radiation alone (1.5 kGy) reduced the total flora by 3 log CFU/g; however, the combination of CJ (0.25%) with irradiation (1.5 kGy) reduced it by ∼5 log CFU/g after 13 days of storage at 4°C. The texture and color of the lettuce treated with the combined treatments changed slightly during storage, and chlorophyll increased by 3.81 μg/mL after 10 days of storage at 4°C. Significant differences in taste and color were observed in lettuce without treatments after 5 days of storage, whereas no difference was observed after the 0.25% CJ or the combined treatments.

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http://dx.doi.org/10.4315/JFP-19-464DOI Listing
December 2020

Gamma irradiation triggers a global stress response in Escherichia coli O157:H7 including base and nucleotides excision repair pathways.

Microb Pathog 2020 Dec 10;149:104342. Epub 2020 Jun 10.

INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, Québec, H7V 1B7, Canada; Research Laboratories in Sciences Applied to Food, Canadian Irradiation Centre, INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, Québec, H7V 1B7, Canada. Electronic address:

Shiga toxin-producing Escherichia coli O157:H7, one of the most severe human foodborne pathogens, can withstand several stresses, including some levels of γ-irradiation. In this study, the response of E. coli O157:H7 to a sensitization irradiation dose of 0.4 kGy was assessed using RNA-seq transcriptomic at 10 (t10) and 60 (t60) min post-irradiation, combined with an isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis at 60 min post-irradiation. Several functions were induced by the treatment, such as base excision repair and nucleotide excision repair pathways; sulfur and histidine metabolism, and virulence mechanisms. Additionally, the sulA gene, coding for the cell division repressor, together with other genes involved in SOS response and repair mechanism (including recA, recN, recJ, recQ, mutM and uvrB) were up-regulated at t60. As the early response to irradiation stress (t10), dnaK, groEL, ibpA, sulfur metabolism genes, as well as those related to oxidative stress were up-regulated, while histidine biosynthesis genes were down-regulated. Acid stress, heat shock, UV resistance and several virulence genes, especially stx2A/stx2b which code for the Shiga toxins characteristic of O157:H7, were upregulated at 60 min post-irradiation. The treatment was also found to increase the levels of CysN, MutM, DinG and DnaC in the cells, proteins involved respectively in sulfur metabolism, base excision repair, recombinational DNA repair and chromosome replication. Our results provide insights into the resistance response of E. coli O157:H7 to a non-lethal irradiation dose. Our findings indicate that E. coli O157:H7 can resist to γ-irradiation through important modifications in genes expression and proteins profiles.
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http://dx.doi.org/10.1016/j.micpath.2020.104342DOI Listing
December 2020

Study of anticancer properties of proanthocyanidin-rich cinnamon extract in combination with Bifidobacterium animalis subsp. lactis BLC1 and resistance of these free and co-encapsulated materials under in vitro simulated gastrointestinal conditions.

Food Res Int 2020 08 26;134:109274. Epub 2020 Apr 26.

Research Laboratory in Sciences Applied to Food, INRS Armand-Frappier Health and Biotechnology Centre, Canadian Irradiation Centre, Institute of Nutrition and Functional Foods (INAF), 531 Boulevard des Prairies, Laval, Quebec H7V 1B7, Canada. Electronic address:

Bifidobacterium animalis subsp. lactis (BLC1) and proanthocyanidin-rich cinnamon extract (PRCE) have many beneficial health properties. However, they are very sensitive materials; co-encapsulation is one alternative to protect them. Therefore, the objective of this work was to evaluate the anticancer properties of free PRCE and in combination with BLC1 and the resistance of these free and co-encapsulated materials under in vitro simulated gastrointestinal conditions. In terms of anticancer proprieties, PRCE had an IC value close to 30 mg extract/mL for Hepa 1c1c7 and HT-29 cells and resulted in a significantly higher percentage (p ≤ 0.05) of total apoptotic and necrotic cells compared to treatment in combination with BLC1 (PRCE + BLC1), with values above 31.66% in both cells. For the quinone reductase (QR) assay, there was a significant increase only for PRCE + BLC1 treatment, with a fold induction of 5.11 ± 0.56 for HT-29. The resistance of the encapsulated materials was greater than for the free form after 240 min of simulated gastrointestinal conditions. The combination of these materials in a microcapsule is advantageous because it protects them under gastrointestinal conditions, allowing them to be released into the intestine and act in the early stages of colon cancer.
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http://dx.doi.org/10.1016/j.foodres.2020.109274DOI Listing
August 2020

Electron beam crosslinking of alginate/nanoclay ink to improve functional properties of 3D printed hydrogel for removing heavy metal ions.

Carbohydr Polym 2020 Jul 30;240:116211. Epub 2020 Mar 30.

Research Laboratories in Sciences Applied to Food, Canadian Irradiation Centre, INRS-Institute Armand-Frappier, 531 des prairies blvd., Laval City, Québec H7V 1B7, Canada.

A printable nanocomposite hydrogel was fabricated with intercalation of alginate into clay galleries followed by irradiation crosslinking graft copolymerization acrylic acid to remove inorganic micropollutants from wastewater. In this regard, nanocomposite-based ink was treated by electron beam irradiation (5-60 kGy), and then irradiated inks were printed using an extrusion-based printer. Structural investigates showed that ink suspension formed a crosslinked network upon irradiation, which could preserve its shape during printing and maintain 3D printed architecture. No additional post-print crosslinking was required due to the formation of free radical and remaining in printed hydrogels as shown by electron spin resonance. Printed hydrogels treated with 5 and 60 kGy irradiation experienced instrumental changes, while functional properties of 15-45 kGy irradiated samples were unaffected upon printing. Losing crystallinity and thermal instability of hydrogels after printing were inhibited through irradiation crosslinking. Metal ion adsorption capacity showed that crosslinked printed hydrogels effectively removed heavy metal ions with high-capacity and fast-responsive. Moreover, metal ions adsorption by printed hydrogels was not selective, thus they can be used to remove various metal ion pollutants from wastewater.
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http://dx.doi.org/10.1016/j.carbpol.2020.116211DOI Listing
July 2020

Chemopreventive Properties of Extracts Obtained from Blueberry ( L.) and Jabuticaba ( Berg.) in Combination with Probiotics.

Nutr Cancer 2021 15;73(4):671-685. Epub 2020 May 15.

Research Laboratory in Sciences, Applied to Food, INRS Armand-Frappier Health and Biotechnology Centre, Canadian Irradiation Centre, Institute of Nutrition and Functional Foods (INAF), Laval, Quebec, Canada.

The association of probiotics and fruit extracts may influence the chemopreventive effect of colorectal cancer. In this context, antiproliferative activity was evaluated to select the best extracts that would be added probiotics, after addition of or in the extracts the antiradical and antioxidant activity, quinone reductase (QR) assay and apoptosis assay were evaluated. Four extracts were isolated: E1: rich in total phenolic compounds; E2: rich in water-soluble phenolic compounds; E3: rich in most apolar phenolic compounds and E4: rich in anthocyanins. The antiproliferative results showed that the best extracts for blueberry and jabuticaba were, respectively the extract E4 and E2. After addition of the probiotic bacteria in these best extracts, it was observed that E2 from jabuticaba presented significantly higher antiradical and antioxidant activity values compared to E4 from blueberry before and after addition of probiotics. There was also a 9-fold increase in activity of QR by the E2 from jabuticaba with (JL). Likewise, this same extract showed a significant increase both in apoptotic and necrotic cells for both cells. In conclusion, extract rich in water-soluble phenolic compounds (E2) from jabuticaba presented a greater chemopreventive effect compared to the others.
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http://dx.doi.org/10.1080/01635581.2020.1761986DOI Listing
May 2020

Correlation between chemical composition and antimicrobial properties of essential oils against most common food pathogens and spoilers: In-vitro efficacy and predictive modelling.

Microb Pathog 2020 Oct 25;147:104212. Epub 2020 Apr 25.

INRS Armand-Frappier, Health and Biotechnology Centre, Research Laboratories in Sciences Applied to Food, Canadian Irradiation Centre, Institut des Nutraceutiques et des Aliments Fonctionnels (INAF), 531, Boulevard des Prairies, Laval, Québec, H7V 1B, Canada. Electronic address:

Using disk diffusion assay and broth microdilution, we evaluated the antimicrobial activity of 38 commercially available essential oils (EOs) against 24 food pathogens and spoilers. These including E. coli O157: H7 (3 types), Listeria (3 types), Bacillus (2 types), Salmonella enterica (2 types), Staphylococcus aureus (3 types), Clostridium tyrobutiricum, Pseudomonas aeruginosa, Brochotrix thermosphacta, Campylobacter jejuni, Carnobacterium divergens, Aspergillus (2 types), and Penicillium (4 types). Correlation between EOs' chemical composition and antimicrobial properties was studied using R software. Moreover, statistical models representing the relationship were generated using Design Expert®. The predictive models identified the chemical attributes of EOs that drive their antimicrobial properties while providing an understanding of their interactions. Thyme (Aldrich, Novotaste), cinnamon (Aliksir, BSA), garlic (Novotaste), Mexican garlic blend N & A (Novotaste), and oregano (BSA) were the strongest antimicrobial. The most sensitive pathogens were P. solitum (MIC of 19.53 ppm) and L. monocytogenes (MIC of 39 ppm). The correlation analysis showed that phenols and aldehydes had the strongest positive effects on the antimicrobial properties followed by the sulfur containing compounds and the esters; while the effects of monoterpenes and ketones were negative. Different sensitivity of food pathogens to chemical families was observed. For instance, phenols and aldehydes exhibited a linear inhibitory effect on L. monocytogenes (LM1045, MIC), while sesquiterpene and ester showed a significant effect on S. aureus (ATCC 6538, MIC). The developed predictive models are expected to predict the antimicrobial properties based on the chemical families of essential oils.
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http://dx.doi.org/10.1016/j.micpath.2020.104212DOI Listing
October 2020

Cellulose nanocrystals (CNCs) loaded alginate films against lipid oxidation of chicken breast.

Food Res Int 2020 06 19;132:109110. Epub 2020 Feb 19.

Research Laboratories in Sciences Applied to Food, Canadian Irradiation Centre, INRS-Armand-Frappier, Health and Biotechnology Centre, Institute of Nutraceutical and Functional Foods, 531 Blvd des Prairies, Laval, Quebec H7V 1B7, Canada. Electronic address:

UV barrier properties and the oxygen permeability (OP) of alginate based films loaded from 0 to 30% CNCs (w/w polymer, dry basis) were evaluated at 0, 50, and 70% RH. The best performing film was used to coat chicken breasts and lipid oxidation was assessed during storage through lipid peroxide value (PV), thiobarbituric acid reagent substances (TBARS) quantification and color variability measurements. Results showed promising UV barrier effects and 25% decrease of OP at 70% RH when 30% CNCs were loaded in alginate films. Edible coating on chicken breasts also demonstrated a decrease of PV and TBARS at day 1 and 3 when 30% CNCs were used and no oxidative changes were indicated by chicken color.
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http://dx.doi.org/10.1016/j.foodres.2020.109110DOI Listing
June 2020

The synergistic effect of cell wall extracted from probiotic biomass containing Lactobacillus acidophilus CL1285, L. casei LBC80R, and L. rhamnosus CLR2 on the anticancer activity of cranberry juice-HPLC fractions.

J Food Biochem 2020 05 17;44(5):e13195. Epub 2020 Mar 17.

Research Laboratories in Sciences Applied to Food, Canadian Irradiation Center, INRS, Armand-Frappier, Health and Biotechnology Center, Institute of Nutraceutical and Functional Foods, Laval, QC, Canada.

Anticancer effects were evaluated on three HPLC fractions obtained from a concentrated cranberry juice and cell wall constituents extracted from a probiotic biomass containing Lactobacillus acidophilus CL1285, Lactobacillus casei LBC80R, and Lactobacillus rhamnosus CLR2. The samples were tested at increasing concentrations for the antiproliferative assay using HT-29 cells' line and for the quinone reductase (QR) assay using Hepa-1c1c7 murine hepatoma cells. Fraction 1 (F1) which is highly concentrated with phenolic acids inhibited the growth of the HT-29 cells' line with IC values of 14.80 µg Gallic acid equivalent (GAE)/ml. The fraction 3 (F3) which is highly concentrated in flavonols had potency as QR inducer. Furthermore, the results showed that all cranberry fractions combined with cell wall constituents extracted from the probiotic biomass were more effective in inhibiting the growth of HT-29 as compared to the cranberry fractions tested alone, indicating a possible synergy effect between these bio-functional compounds. PRACTICAL APPLICATIONS: This study strongly evidenced that cranberry juice fractions combined with cell wall constituents extracted from the probiotic biomass can be used as a potent preventive functional compound against colorectal cancer. Therefore, this research proposes a natural dietary compound to prevent mutagenesis and carcinogenesis of colorectal cancer. Furthermore, the industry can formulae products containing probiotic and phenolic compounds as colon cancer cell growth preventive and anticancer products.
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http://dx.doi.org/10.1111/jfbc.13195DOI Listing
May 2020

Microbial radiosensitization using combined treatments of essential oils and irradiation- part B: Comparison between gamma-ray and X-ray at different dose rates.

Microb Pathog 2020 Jun 6;143:104118. Epub 2020 Mar 6.

Research Laboratories in Sciences Applied to Food, Canadian Irradiation Center, INRS-Institute Armand-Frappier, 531, Boulevard des Prairies, Laval, Quebec, H7V 1B7, Canada. Electronic address:

Stored rice and rice products are prone to contamination by pathogenic fungi and bacteria such as Aspergillus niger, Bacillus cereus, and Paenibacillus amylolyticus. Treatment with antimicrobial essential oils (EOs) and irradiation are options to control spoilage organisms. Microbial samples with or without fumigation with an oregano/thyme EO mixture were irradiated at 0.5, 0.75, 1.0, 1.5, 2.0, 2.5, 3.0 and 3.5 kGy for calculation of a D value. The relative sensitivity was calculated as the ratio of D10 values for the irradiation plus oregano and thyme EO combination and irradiation alone treatments. In all cases, irradiation plus fumigation with the oregano and thyme EO mixture showed increased efficacy compared with irradiation alone. The relative sensitivity of γ-ray irradiation against A. niger was 1.22, 1.33, and 1.24 for radiation dose rates of 10.445, 4.558, and 0.085 kGy/h, respectively, however against B. cereus it was 1.28, 1.45, and 1.49, and against P. amylolyticus it was 1.35, 1.33, and 1.38, for respective γ-ray irradiation dose rates. The relative sensitivity of X-ray irradiation against A. niger, B. cereus, and P. amylolyticus was 1.63, 1.21, and 1.31, respectively, at the X-ray dose rate of 0.76 kGy/h. The results showed that the relative sensitivity of γ-ray irradiation was higher against the two bacteria than the fungus, whereas X-ray showed higher sensitivity against the fungus than the two bacteria. There was no consistent positive or negative relationship between dose rate and relative sensitivity. The results demonstrated the potential of an oregano and thyme EOs mixture as an antimicrobial agent and its efficacy to increase the radiosensitization of A. niger, B. cereus, and P. amylolyticus during γ-ray or X-ray irradiation treatments.
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http://dx.doi.org/10.1016/j.micpath.2020.104118DOI Listing
June 2020

Potential synergistic antimicrobial efficiency of binary combinations of essential oils against Bacillus cereus and Paenibacillus amylolyticus-Part A.

Microb Pathog 2020 Apr 25;141:104008. Epub 2020 Jan 25.

Research Laboratory in Sciences, Applied to Food, INRS Armand-Frappier Health and Biotechnology Centre, Canadian Irradiation Centre, Institute of Nutrition and Functional Foods (INAF), 531 Boulevard des Prairies, Laval, Quebec, Canada, H7V 1B7. Electronic address:

The checkerboard method was used to study the potential interactions between eight essential oils (Basil, Cinnamon, Eucalyptus, Mandarin, Oregano, Peppermint, Tea tree, and Thyme) when used as antibacterial agents against Bacillus cereus LSPQ 2872 and Paenibacillus amylolyticus ATCC 9995. The minimum inhibitory concentration (MIC) of each essential oil (EO) and the fractional inhibitory concentration (FIC) index for the binary combinations of essential oils (EOs) were determined. According to FIC index values, some of the compound binary combinations showed an additive effect; however, Thyme/Tea tree and Cinnamon/Thyme EOs exhibited a synergistic effect against P. amylolyticus and B. cereus, respectively. Cinnamon/Thyme EOs mixture exhibited no interactive effect against P. amylolyticus, but a synergistic effect against B. cereus. The combination of Oregano/Thyme EOs displayed the best antibacterial activity and showed a synergistic effect against B. cereus and P. amylolyticus bacteria. The Oregano/Thyme EOs mixture has potential application in food preservation to reduce the contamination of B. cereus and P. amylolyticus.
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http://dx.doi.org/10.1016/j.micpath.2020.104008DOI Listing
April 2020

Development of support based on chitosan and cellulose nanocrystals for the immobilization of anti-Shiga toxin 2B antibody.

Carbohydr Polym 2020 Mar 26;232:115785. Epub 2019 Dec 26.

Research Laboratories in Sciences, Applied to Food, Canadian Irradiation Center, INRS, Armand-Frappier, Health Biotechnology Centre, Institute of Nutraceutical and Functional Foods, 531 Blvd des Prairies, Laval, QC H7V 1B7, Canada. Electronic address:

This work describes the development of membrane based on chitosan (CHI), cellulose nanocrystals (CNCs), and glycerol (GLY), and optimization of the formulation for immobilization of monoclonal anti-Shiga toxin 2B antibody (mAnti-stx2B-Ab) for E. coli O157:H7 detection. The effect of CHI deacetylation degree & viscosity, CNCs and GLY concentrations on Anti-stx2B-Ab immobilization efficiency was evaluated. Fractional factorial and Box-Behnken designs were applied to screen the effects of compounds interactions and optimize their concentrations for detection of Anti-stx2B-Ab. The results demonstrated that the use of 0.6 % (w/v) CNCs improved significantly the Anti-stx2B-Ab immobilization and the level of signal detection. The detection limit of Escherichia coli O157:H7 by developed optimized membrane is 1 log CFU/mL. The time needed for detection of E. coli O157:H7 was only 4 h of enrichment compared to 24 h with conventional methods. The developed immobilization support has potential for future pathogen detection in food and biomedical samples.
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http://dx.doi.org/10.1016/j.carbpol.2019.115785DOI Listing
March 2020

Novel spider web trap approach based on chitosan/cellulose nanocrystals/glycerol membrane for the detection of Escherichia coli O157:H7 on food surfaces.

Int J Biol Macromol 2020 Mar 11;146:1009-1014. Epub 2019 Nov 11.

Research Laboratories in Sciences Applied to Food, Canadian Irradiation Center, INRS-Institut Armand Frappier, Institute of Nutrition and Functional Foods, 531 Boulevard des Prairies, Laval, QC H7V 1B7, Canada. Electronic address:

The aim of this study was to develop a novel approach allowing simultaneous enrichment as well as specific and fast detection of Escherichia coli O157:H7 by indirect ELISA using optimized support membrane based on chitosan (CHI), cellulose nanocrystals (CNCs), and glycerol (GLY). Therefore, combining the step of the capture of the pathogen and enrichment steps for the microbial growth led to a high detection signal at a low inoculation level without cross-reaction with Pseudomonas and Salmonella strains. The detection was performed by varying incubation periods and different level of inoculations. The signal of detection in samples incubated with the chitosan-based support reinforced with CNCs and directly from E. coli O157:H7 bacterial culture was much higher as compared to CNCs-free support with cell-free supernatant samples. The CCG support reinforced with 0.6% CNCs improved the detection signal of E. coli O157:H7 by 25% compared to control. The whole bacterial culture showed a higher immobilization signal than unfiltered and cell-free supernatant. The spider web trap approach (SWTA) detect E. coli O157:H7 after only 4 h of enrichment compared to 24 h with conventional methods. The adjustment of this innovative SWTA could minimize the risks of cross-contamination and consequently, food product recalls by facilitating significantly the detection of foodborne pathogens in samples collected from food surface, tools and work surfaces in food processing industries.
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http://dx.doi.org/10.1016/j.ijbiomac.2019.09.225DOI Listing
March 2020

Antimicrobial Properties of Encapsulated Antimicrobial Natural Plant Products for Ready-to-Eat Carrots.

Foods 2019 Nov 1;8(11). Epub 2019 Nov 1.

Research Laboratories in Sciences Applied to Food, Canadian Irradiation Center, INRS-Armand Frappier, Health and Biotechnology Center, Institute of Nutraceutical and Functionals Foods, 531 Boulevard des Prairies, Laval, QC H7V 1B7, Canada.

The antimicrobial activity of natural antimicrobials (fruit extracts, essential oils and derivates), was assessed against six bacteria species ( O157:H7, , . Typhimurium, , and ), two molds ( and ) and a yeast () using disk diffusion method. Then, the antimicrobial compounds having high inhibitory capacity were evaluated for the determination of their minimum inhibitory, bactericidal and fungicidal concentration (MIC, MBC and MFC respectively). Total phenols and flavonoids content, radical scavenging activity and ferric reducing antioxidant power of selected compounds were also evaluated. Based on in vitro assays, five antimicrobial compounds were selected for their lowest effective concentration. Results showed that, most of these antimicrobial compounds had a high concentration of total phenols and flavonoids and a good anti-oxidant and anti-radical activity. In situ study showed that natural antimicrobials mix, applied on the carrot surface, reduced significantly the count of the initial mesophilic total flora (TMF), molds and yeasts and allowed an extension of the shelf-life of carrots by two days as compared to the control. However, the chemical treatment (mix of peroxyacetic acid and hydrogen peroxide) showed antifungal activity and a slight reduction of TMF.
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http://dx.doi.org/10.3390/foods8110535DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6915581PMC
November 2019

Synergistic Effects of Nanocomposite Films Containing Essential Oil Nanoemulsions in Combination with Ionizing Radiation for Control of Rice Weevil Sitophilus oryzae in Stored Grains.

J Food Sci 2019 Jun 20;84(6):1439-1446. Epub 2019 May 20.

Research Laboratories in Sciences Applied to Food, Canadian Irradiation Centre, INRS-Inst. Armand-Frappier, 531 boulevard des Prairies, Laval, H7V 1B7, Québec, Canada.

The fumigant toxicity of eight individual essential oils (EOs; basil, cinnamon, eucalyptus, mandarin, oregano, peppermint, tea tree, and thyme) and one binary combination (thyme and oregano) for control of the rice weevil, Sitophilus oryzae, were investigated. In bioassays, all individual and combined EOs were toxic to the rice weevil. Eucalyptus EO exhibited the highest toxicity among the individual EO treatments, causing 100% mortality at a minimum concentration of 0.8 µL/mL after 24 hr of exposure. The combination treatment of oregano and thyme EO displayed higher fumigant activity than the individual oregano or thyme treatments. A stable oil-in-water nanoemulsion was evaluated using high-pressure homogenization (microfluidization [MF]) and varying the pressure and number of cycles. The droplet size of the emulsions was found to decrease from 217 to 71 nm and encapsulation efficiency increased from 37% to 84% with increasing MF pressure and number of cycles. The optimum conditions for preparing the mixture of oregano and thyme EO nanoemulsions were evaluated to be homogenization pressure of 103 MPa and three cycles. Incorporating an oregano:thyme nanoemulsion (0.75%) into cellulose nanocrystal (CNC) containing chitosan (CH/CNC), methyl cellulose (MC/CNC), and polylactic acid (PLA/CNC) composite films resulted in extended diffusion matrices causing 32% to 51% rice weevil mortality after 14 days exposure. Irradiation at 200 Gray alone caused 79% mortality and increased to 100% when combined with the bioactive chitosan film containing the oregano:thyme nanoemulsion. PRACTICAL APPLICATION: A binary combination of oregano:thyme has potential as a biopesticide against stored product pests. The encapsulation of EO nanoemulsions into biopolymeric support could be used for bioactive packaging to prevent food spoilage and extend shelf life. Combining bioactive films with irradiation can provide complete control of rice weevil in packaged rice. The system developed in this research may also be extended to explore other food-packaging films with various food models to control different types of stored pests.
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http://dx.doi.org/10.1111/1750-3841.14603DOI Listing
June 2019

Effect of the optimized selective enrichment medium on the expression of the p60 protein used as Listeria monocytogenes antigen in specific sandwich ELISA.

Res Microbiol 2019 Jun - Aug;170(4-5):182-191. Epub 2019 Apr 3.

INRS-Institut Armand-Frappier, Research Laboratories in Sciences Applied to Food, Canadian Irradiation Centre, 531 boulevard des Prairies, Laval, Quebec, H7V 1B7, Canada. Electronic address:

This paper presents the effects of the composition of different media (i.e., Tryptic soy broth (TSB), Brain heart infusion (BHI), Listeria enrichment broth (LEB), Fraser broth (FB) and University of Vermont medium (UVM)) on the detection of a short peptide fragment PepD specific to the p60 protein (p60) of L. monocytogenes by a monoclonal antibody (anti-PepD mAb). Expression of the p60 obtained was demonstrated to be proportional to the cellular growth of Listeria monocytogenes regardless of the tested growth medium. However, the early growth of L. monocytogenes and the expression of the p60 were negatively affected by the presence of selective agents present in LEB, FB and UVM. Among those three selective enrichment media commonly used for L. monocytogenes, LEB allowed a better expression of L. monocytogenes p60 after an incubation period of 18 h. Optimization of the LEB revealed that the dextrose concentration was the critical factor for improving the expression of p60 and promotes the early expression of p60. Moreover, an optimal dextrose concentration of 0.5% (w/v) in LEB, coupled with anti-PepD mAb immobilized to solid support, reduced the detection of p60 from 18 h to 9 h for an initial concentration of L. monocytogenes of 10 CFU/ml.
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http://dx.doi.org/10.1016/j.resmic.2019.03.004DOI Listing
August 2019

Antifungal activities of combined treatments of irradiation and essential oils (EOs) encapsulated chitosan nanocomposite films in in vitro and in situ conditions.

Int J Food Microbiol 2019 Apr 12;295:33-40. Epub 2019 Feb 12.

Research Laboratories in Sciences Applied to Food, Canadian Irradiation Centre, INRS-Institute Armand-Frappier, 531 des prairies blvd., Laval City, Québec H7V 1B7, Canada. Electronic address:

Cellulose nanocrystals (CNCs) reinforced chitosan based antifungal films were prepared by encapsulating essential oils (EOs) nanoemulsion. Vapor phase assays of the chitosan-based nanocomposite films loaded with thyme-oregano, thyme-tea tree and thyme-peppermint EO mixtures showed significant antifungal activity against Aspergillus niger, Aspergillus flavus, Aspergillus parasiticus, and Penicillium chrysogenum, reducing their growth by 51-77%. Combining the bioactive chitosan films loaded with thyme and oregano EOs produced ~2 log reduction in fungal growth in inoculated rice during 8 weeks of storage at 28 °C. The bioactive films showed a slow release (26%) of volatile components over 12 weeks of storage. Sensorial evaluation of rice samples packed with the bioactive films showed no significant change in odor, taste, color and general appreciation compared with untreated rice. Incorporation of cellulose nanocrystals (CNCs) with the chitosan matrix played an important role in stabilizing the physicochemical and release properties of the nanocomposite films. In addition, combining the bioactive chitosan films with a dose of 750 Gy of ionizing radiation showed significantly higher antifungal and mechanical properties than treatment with the bioactive film or irradiation alone.
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http://dx.doi.org/10.1016/j.ijfoodmicro.2019.02.009DOI Listing
April 2019

Effect of β-lactam antibiotic resistance gene expression on the radio-resistance profile of O157:H7.

Heliyon 2018 Dec 1;4(12):e00999. Epub 2018 Dec 1.

Research Laboratories in Sciences Applied to Food, Canadian Irradiation Center, INRS-Institut Armand-Frappier, Institute of Nutraceutical and Functional Foods, 531 Boulevard des Prairies, Laval, Québec, H7V 1B7, Canada.

Some pathogens might develop favorable global adaptation in response to certain stress treatments resulting in enhanced virulence and/or resistance to a different stress. β-lactam resistance, as well as and genes involved in this resistance, were studied to evaluate their possible role in O157:H7 () radioresistance. adapted to 25, 15 or 7 μg/mL of kanamycin or carbenicillin, were produced and treated with sensitization (0.4 kGy) or lethal (1.5 kGy) irradiation doses. In O157:H7, irradiation treatment at 0.4 kGy dose increased and expression respectively by 1.6 and 2-fold in the wild type strain (Wt) but up to by 2.4 and 3.4-fold when the strain was beforehand adapted to 25 μg/mL of carbenicillin (Carb25). Accordingly, Δ and Δ mutants and adapted to 25 μg/mL of kanamycin were more sensitive to 0.4 kGy treatment than Wt. While, Carb25 or overexpression of and provided complete resistance to 0.4 kGy and were even able to survive and grow after exposure to a normally lethal 1.5 kGy irradiation dose. We further noticed that these strains can tolerate other stresses like oxidative, cold and heat shocks. This demonstrates that carbenicillin adaptation promotes resistance to γ-irradiation and to other stresses, likely at least through increased AmpC and AmpG expression. These results are important for the food industry and particularly when considering the use of irradiation for food preservation of meat obtained directly from animals fed β-lactam antibiotics.
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http://dx.doi.org/10.1016/j.heliyon.2018.e00999DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6278725PMC
December 2018

Effect of Saccharomyces Boulardii Cell Wall Extracts on Colon Cancer Prevention in Male F344 Rats Treated with 1,2-Dimethylhydrazine.

Nutr Cancer 2018 May-Jun;70(4):632-642. Epub 2018 Apr 26.

a INRS-Institut Armand-Frappier, Research Laboratories in Sciences Applied to Food , Laval , Quebec , Canada.

The effect of Saccharomyces boulardii cell wall extracts on colon cancer prevention in rats treated with 1,2-dimethylhydrazine was investigated. A crude insoluble glucan (0.5 and 1.0 mg/kg/day) and a crude mannoprotein extract (0.3 and 3.0 mg/kg/day) were administered in rats by gavage for 12 weeks along with a high fat low fiber diet whereupon rats were sacrificed and aberrant crypt foci (ACF) were counted in the colon. Moreover, NAD(P)H: quinone reductase (QR) and harmful fecal enzymes (β-glucosidase and β-glucuronidase) were quantified in the liver and in the caecum, respectively. Results showed a reduction in ACF counts, a decreased β-glucuronidase activity and an increased QR activity when rats were treated only with insoluble glucan. While these enzymatic modulations may be constituted one of the mechanisms that is responsible for the reduction of ACF counts observed, the reduction of ACF counts caused by insoluble glucan should be addressed, at least, as a biomarker of their cancer-prevention properties. To our knowledge, this is the first study demonstrated that crude cell wall extract obtained from S. boulardii could have a potential role in colon cancer prevention in vivo by revealing the potential implication of QR and β-glucuronidase modulation.
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http://dx.doi.org/10.1080/01635581.2018.1460672DOI Listing
February 2019
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