Foodborne Pathogens Detection: Persevering Worldwide Challenge

According to Health Canada, foodborne disease is responsible of more than 4 million cases per year. In United States, more than 48 million people get sick, 128,000 are hospitalized and 3000 die every year in United States due to foodborne diseases according to the Center for Disease Control and Prevention. Cross-contamination from the raw materials, during the process or on working surface has to be rapidly detected. Good manufacturing practices (GMP) and hazard analysis critical control point (HACCP) can help to reduce the incidence of contamination. However, the development of sensitive and rapid methods of detection is still an important need. Standard culture-based methods request the consumption of large amounts of media, are time-consuming and interferences can occur when samplings are done in complex food matrices. The polymerase chain reaction (PCR)-based methods are new technologies. These methods show high level of specificity and sensitivity because they can detect nucleic acid sequences of target bacteria. However, they require an expensive instrumentation and trained scientific technicians. This review is focusing on the development of new simple, sensitive, specific, and time-saving technologies in order to detect quickly foodborne pathogens for application in food industries

Nanocellulose in Food Packaging

International audienc

Antibacterial properties of combined non-thermal treatments based on bioactive edible coating, ozonation, and gamma irradiation on ready-to-eat frozen green peppers: evaluation of their freshness and sensory qualities

Bibliografi hlm. 162164 hlm.; 21 cm

Effect of antimicrobial coatings on microbiological, sensorial and physico-chemical properties of pre-cut cauliflowers

International audienceSix coatings containing different ratios of polysaccharides and antimicrobials were prepared and tested in vitro against Listeria monocytogenes. Best coating mixtures were then applied on vegetables and submitted to a sensorial analysis. Finally, their effect on the quality, the color and the consistency of vegetables during a one-week storage was determined. All selected coatings showed a total in vitro inhibition of bacteria at concentrations of 8–10 mL L−1. One formulation containing the antimicrobials induced vegetables to have similar characteristics (smell, taste and texture) as compared to the non-treated vegetables. Treatments with this coating generated minor changes concerning the respiration rate and no differences were visually observed on cauliflowers. Finally, in situ analyses showed a good antimicrobial effect and allowed a complete inhibition of Listeria innocua after seven days of storage at 4 °C

Free radical grafting of gallic acid (GA) on cellulose nanocrystals (CNCS) and evaluation of antioxidant reinforced gellan gum films

International audienceAntiradical properties were introduced on cellulose nanocrystals (CNCs) by redox pair (RP) initiator and γ-radiation treatments. Different procedures were tested on CNC, first a 2 h reaction of hydrogen peroxide (H2O2)/ascorbic acid (AA) was performed on CNC solution. γ-Radiation treatment at 20 kGy dose was then applied and immediately after GA was reacted during 24 h with the pretreated CNCs, giving CNC-H2O2-AA-γ-GA. The formation of new carboxylic acids and carbonyl groups were characterized by FT-IR at 1650 and 1730 cm−1 respectively. Carboxylic acid functionalities were also analyzed by conductometric titration where an increase from 49 to 134 mmol COOH kg−1 was found from native to irradiated CNCs. A similar increase in the carboxylic acid content (132 mmol kg−1) was observed for CNC-H2O2-AA-γ-GA, showing the highest radical scavenging properties (8 mM Trolox eq/mg CNC). Thermogravimetric analysis confirmed the structural changes onto CNC. Film packaging containing 20% of CNC-H2O2-AA-γ-GA was then added to a gellan-based film packaging. A significant improvement (p<0.05) of the tensile strength (TS), the tensile modulus (TM) and the elongation at break (EB) and water vapor permeability reduction was observed when CNC-H2O2-AA-γ-GA was added to the film packaging formulation

Cancer Chemopreventive, Antiproliferative, and Superoxide Anion Scavenging Properties of Kluyveromyces marxianus and Saccharomyces cerevisiae var. boulardii Cell Wall Components

International audienceThis study investigated the cancer chemopreventive, the antiradical, and the antiproliferative properties of polysaccharides extracts from cell wall of Saccharomyces boulardii and Kluyveromyces marxianus. β-glucan, mannan, and chitin were also quantified to identify the most important extract responsible for these biological properties. Soluble and insoluble glucans as well as mannoprotein were extracted from cell wall using single hot-alkaline method. Superoxide anion scavenging (antiradical capacity), NAD(P)H: quinone reductase (QR) (EC 1.6.99.2) induction, and antiproliferative assays were done for the evaluation of biological properties of those extracts. The insoluble glucan from S. boulardii revealed the most relevant biological properties by increasing QR activity and exhibiting the highest growth inhibition against colorectal cancer cells. Moreover, high amount of glucan, high glucan/total sugars ratios, and low chitin/glucan ratios were shown to have an impact on enhancing cancer chemopreventive and antiproliferative properties. To our knowledge, this is the first study that demonstrates QR activity by yeast cell wall components in a dose-dependent manner

Antibacterial and physical effects of modified chitosan based-coating containing nanoemulsion of mandarin essential oil and three non-thermal treatments against Listeria innocua in green beans

The antimicrobial activity against Listeria innocua of three different combined non-thermal treatments, along with the impact on color and texture on green bean samples, was evaluated. In this study a bioactive coating formulation based on modified chitosan containing 0.05% nanoemulsion of mandarin essential oil was tested in combination with γ-irradiation, UV-C and ozonated water treatments, and the results in terms of antimicrobial activity, color and texture changes, were evaluated during 14. days storage. The combined coating and γ-irradiation treatment gave promising results, showing 3.3 log CFU/g initial microbial reduction, and exhibiting a strong synergistic antimicrobial effect. The treatment based on UV-C and coating formulation allowed a 3 log CFU/g reduction of initial L. innocua population on samples, showing a good residual antimicrobial activity and preventing loss of firmness and color changes during storage. The combined treatment of coating and ozonated water did not show any synergistic or additive antimicrobial effect, but they showed an impact on firmness and color. In conclusion UV-C and γ-irradiation treatments, in combination with the bioactive coating, represent an effective approach to control the growth of L. innocua on vegetable foods

Effect of Physical and Enzymatic Pre-Treatment on the Nutritional and Functional Properties of Fermented Beverages Enriched with Cricket Proteins

The aim of this study was to evaluate the effects of γ-irradiation (IR), ultrasound (US), and combined treatments of ultrasound followed by γ-irradiation (US-IR), ultrasound followed by enzymatic hydrolysis with and without centrifugation (US-E and US-EWC, respectively), and ultrasound followed by γ-irradiation and enzymatic hydrolysis (US-IRE), on the digestibility and the nutritional value of fermented beverages containing probiotics. Results showed that US (20 min), IR (3 kGy) and US-IR (tUS = 20 min, dose = 3 kGy) treatments raised protein solubility from 11.5 to 21.5, 24.3 and 29.9%, respectively. According to our results, these treatments were accompanied by the increased amount of total sulfhydryl groups, surface hydrophobicity and changes to the secondary structure of the proteins measured by Fourier-transform infrared spectroscopy (FTIR). Fermented probiotic beverages, non-enriched (C) and enriched with untreated (Cr) or treated cricket protein with combined treatments were also evaluated for their in vitro protein digestibility. Results showed that the soluble fraction of US-IRE fermented beverage had the highest digestibility (94%) as compared to the whole fermented tested beverages. The peptides profile demonstrated that US-IRE had a low proportion of high molecular weight (MW) peptides (0.7%) and the highest proportion of low MW peptides by over 80% as compared to the other treatments