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International audience; Cancer chemopreventive properties were evaluated in HPLC fractions of different polarity obtained from two cranberry juices and three extracts isolated from frozen cranberries and pomace containing anthocyanins, water-soluble and apolar phenolic compounds, respectively. Compounds with close polarities were collected in order to obtain between three and four fractions from each juice or extract. Cranberry fractions were screened for their ability to induce the phase II xenobiotic detoxification enzyme quinone reductase (QR). The results showed that there was no cytotoxicity against the cells used in the test. All samples stimulated the quinone reductase activity except the highest concentrations of the less polar fraction of anthocyanin-rich extract from pomace, which inhibited the QR activity. The QR induction for all samples varied with the concentration and there was an optimal concentration for which the QR induction was maximal. The technological process to manufacture cranberry juice had little influence on the overall QR inducer potencies of cranberry fractions, whereas the ability of phenols in fractions to stimulate the QR activity has been reduced significantly (P ≤ 0.05) during the technological process. Among all samples, phenolic compounds of eight fractions presented a maximum QR induction greater than 100 II(QR)/mg phenol. The phenolic compounds of the most polar fraction (rich in phenolic acids) and those of the less polar fraction (rich in proanthocyanidins) showed stronger induction than those observed with phenols from intermediate fractions.

Lipid peroxidation inhibition capacity and antiradical activity were evaluated in HPLC fractions of different polarity obtained from two cranberry juices and three extracts isolated from frozen cranberries and pomace containing antho-cyanins, water-soluble and apolar phenolic compounds, respectively. Compounds with close polarities were collected to obtain between three and four fractions from each juice or extract. The cranberry phenols are good free radi-cal-scavengers, but they were less efficient at inhibiting the lipid peroxidation. Of all the samples tested, the intermediate polarity fraction of extract rich in apolar phenolic compounds of fruit presented the highest antiradical activity while the most hydrophobic fractions of the anthocyanin-rich extract from fruit and pomace appeared to be the most efficient at inhibiting the lipid peroxidation. The antioxidant or pro-oxidant activity of fractions increased with the con-centration. The phenol polarity and the technological process to manufacture cranberry juice can influence the antioxidant and antiradical activities of fractions.

The effects of the industrial juice process on the ability of neutralized cranberry samples and extracts (polar, apolar and anthocyanins) to inhibit the growth of Enterococcus faecium resistant to vancomycin (ERV), Escherichia coli O157:H7 EDL 933, E. coli ATCC 25922, Listeria monocytogenes HPB 2812, Pseudomonas aeruginosa ATCC 15442, Salmonella Typhimurium SL1344 and Staphylococcus aureus ATCC 29213 were investigated. The juice process appeared to have a general enhancing effect on the antibacterial properties of cranberry polar and anthocyanin extracts. The lowest minimum inhibitory concentrations (MICs) (1.80–7.0 μg phenol/well) were obtained when S . aureus , S . Typhimurium, and ERV were exposed to the juice concentrate. The growth of P . aeruginosa , L . monocytogenes , E . coli ATCC, and E . coli O157:H7 was not inhibited by the juice concentrate, but did show sensitivity (maximal tolerated concentrations of 0.007–0.4 μg phenol/well). The lowest MICs (22.6–90.5 μg phenol/well) for P . aeruginosa , S . aureus , S . Typhimurium, and ERV were observed when they were exposed to the cranberry anthocyanin extract obtained from cranberry pomace. The results also showed a negative effect of the juice process on the antibacterial properties of the cranberry apolar extracts: the one obtained from frozen cranberries was most efficient against P . aeruginosa , S . aureus , L . monocytogenes and S . Typhimirium (MIC of 45.50 μg phenol/well). The tested bacteria showed the greatest resistance toward the cranberry extracts obtained from the mash and the macerated and depectinized mash.

International audience; The effects of the industrial juice process on the antioxidant capacities of cranberry samples and of three phenolic extracts (polar phenolics (E1), apolar phenolics (E2) and anthocyanins (E3)) adjusted at pH 2.5 and 7.0 were investigated. The free radical-scavenging (FRS) and the lipid peroxidation inhibition (LPI) activities of each sample and extract, were studied using a N,N-diethyl-p-phenylenediamine discoloration test and the thiobarbituric acid reactive substances assay, respectively. The FRS and the LPI results, expressed in mM Trolox® equivalent (TE)/mg phenol and mg TE/mL/mg phenol, respectively, showed a negative effect of the juice process steps on E1. The E2 and E3 extracts were also affected by the process but not as much. The milling step increased the FRS capacity of E2 and E3 extracts, but decreased their LPI capacity. The evaporation of the juice did not have a significant effect on the FRS capacity, but lowered the LPI capacity. Before and after each step of the juice process, the FRS capacity of the cranberry extracts was greater than the LPI capacity. The results were consistent in classifying the FRS capacity of the extracts in the following order of polarity: E1>E3>E2; and their total phenolic (TP) content in the following order: E3>E2>E1. In general, the neutralization of the pH of the extracts did not significantly influence the changes observed during the juice process in the FRS and LPI capacity, except for E3 for which a decrease in the LPI capacity was observed.

International audience; The antioxidant capacities of cranberry juice and three extracts isolated from frozen cranberries containing anthocyanins, water-soluble and apolar phenolic compounds, were evaluated at pH 2.5 and 7, respectively. The free radical-scavenging (FRS) and the lipid peroxidation inhibition (LPI) activities of each samples, and extracts, were studied using the N,N-diethyl-p-phenylenediamine (DPD) decoloration test and the thiobarbituric acid reactive substances (TBARS) assay, respectively. The cranberry phenols displayed good free radical-scavenging properties, but were less efficient at inhibiting the peroxidation of lipids. Of all the samples tested, the water-soluble phenolic compounds showed the greatest free radical-scavenging (68.2 mmol TE/mg phenol) and antioxidant (13.4 mmol TE phenol) activities. The polarity of the phenols, the pH of the medium and the juice process had a great influence on the antioxidant activities. The phenols isolated from cranberries with an aqueous solvent have greater antioxidant properties than those extracted with an organic solvent mixture. The antioxidant activity of the cranberry samples adjusted at pH 2.5 was greater than those adjusted at pH 7. Compared to the cranberry extracts, the juice exhibited a much lower antioxidant activity, especially when compared with the extract containing water-soluble compounds which the extraction conditions were similar to those used to obtain the juice.

International audience; Cancer chemopreventive properties were evaluated in cranberries and cranberry products (mash, depectinized mash, pomace, raw juice, clarified juice and juice concentrate). Three extracts isolated from frozen cranberries and cranberry solids (mash, depectinized mash and pomace) containing anthocyanins, water-soluble and apolar phenolic compounds were tested. Cranberry juices and extracts were screened for their ability to induce the phase II xenobiotic detoxification enzyme quinone reductase (QR). The results showed that there was no cytotoxicity against the cells used in the test. All samples stimulated quinone reductase activity except the highest concentrations of the anthocyanin-rich extract of pomace, which inhibited QR activity. Also, the results showed that the QR induction for all samples varied with concentration and that there was an optimal concentration for which the QR induction was maximal. Although the three cranberry extracts were good QR inducers, our results indicated that the phenols present in aqueous extract showed QR inductions which were more important than those obtained with phenols present in solvent extracts. Also, the ability of phenols to stimulate the QR activity has been reduced continuously and significantly (P ≤ 0.05) during the technological process. Especially, it appears that conditions of the evaporation to obtain a juice concentrate exerted a significant effect (P ≤ 0.05) on inducer potencies of bioactive molecules.

Antimutagenic activities of pure commercial chemicals and food supplements were compared with that of herb extracts using a method based on the umu test system for screening natural antimutagens. Of the 55 products investigated, 22 were commercial products, 12 were food supplements and 21 were aqueous and ethylic herb infusions. All commercial products showed antimtagenic properties. BHT was shown to be a very strong antimutagen. All food supplements showed medium or neutral antimutagenic properties, except for echinaforce and coenzyme-Q10 which behaved as mutagenic products. All herbs showed antimutagenic properties except Italian parsley that had mutagenic activity. With regard to the metabolites, those from commercial products showed antimutagenic properties, except those from BHA and especially Biochanin A that showed high mutagenic activity. All metabolites from food supplements showed antimutagenic properties, except those from Fluxarola that showed antimutagenic properties. Metabolites from most herb extracts showed antimtagenic properties and those from thyme showed very strong antimutagenic activities, while those from camomile, rosemary and tarragon showed mutagenic activities, and those from celeriac and sage showed very strong mutagenic activities.

A fortified beverage powder intended for developing countries was composed of vitamins, minerals, sugar and orange flavor. Organic acids were also added as food additive. The antibacterial efficacy of reconstituted beverage was tested on three strains of enterobacteria ( Escherichia coli , Salmonella Typhi and Serratia liquefaciens ). The antibacterial efficacy of beverage containing organic acids (ascorbic and citric acids) as compared to the same beverage containing mineral acid was successfully demonstrated. The greatest inhibitions of bacterial growth were observed in the presence of organic acids. The antibacterial activity was significant depending on initial bacterial concentration and time of contact. However, S. liquefaciens was not detected in the beverage containing organic acids regardless of the bacterial concentration added. At a concentration of 10 3 cells/mL, the bacterial population of S. liquefaciens , E. coli , S. Typhi and the mixture of the three bacteria reached an undetectable level in the beverage containing organic acids after 5, 180, 180 and 60 min of contact, respectively. The inhibitory effect of pathogenic bacteria was closely related to the reduction of the beverage pH and to the concentration of undissociated organic acids.

The aim of this study was to investigate how mustard essential oil (EO) affected the cell membrane of Escherichia coli O157:H7 and Salmonella typhi. Intracellular pH and ATP concentration and the release of cell constituents were measured when mustard EO was in contact with E. coli and S. typhi at its minimal inhibitory concentration (MIC) and maximal tolerated concentration (MTC). The treatment with mustard EO affected the membrane integrity of bacteria and induced a decrease of the intracellular ATP concentration. Also, the extracellular ATP concentration increased and a reduction of the intracellular pH was observed in both bacteria. A significantly (P ⩽ 0.05) higher release of cell constituent was observed when both bacteria cells were treated with mustard EO. Electronic microscopy observations showed that the cell membranes of both bacteria were apparently damaged by mustard EO. In conclusion, mustard EO affects the concentration of intracellular component, such as ATP in both bacteria and affects the pH suggesting that cytoplasmic membrane is involved in the antimicrobial action of mustard EO. Mustard EO can be used as an effective antimicrobial agent. We have demonstrated that mustard EO affected the cell membrane integrity, resulting in a loss of cell homeostasis.

Spice extracts under the form of essential oils were tested for their efficiency to increase the relative radiosensitivity of Listeria monocytogenes and Escherichia coli O157H7 in culture media. The two pathogens were treated by gamma-irradiation alone or in combination with oregano essential oil to evaluate their mechanism of action. The membrane murein composition, and the intracellular and extracellular concentration of ATP was determined. The bacterial strains were treated with two irradiation doses: 1.2 kGy to induce cell damage and 3.5 kGy to cause cell death for L. monocytogenes. A dose of 0.4 kGy to induce cell damages, 1.1 kGy to obtain viable but nonculturable (VBNC) state and 1.3 kGy to obtain a lethal dose was also applied on E. coli O157H7. Oregano essential oil was used at 0.020% and 0.025% (w/v), which is the minimum inhibitory concentration (MIC) for L. monocytogenes. For E. coli O157H7, a concentration of 0.006% and 0.025% (w/v) which is the minimum inhibitory concentration was applied. The use of essential oils in combination with irradiation has permitted an increase of the bacterial radiosensitization by more than 3.1 times. All treatments had also a significant effect (p⩽0.05) on the murein composition, although some muropeptides did not seem to be affected by the treatment. Each treatment influenced differently the relative percentage and number of muropeptides. There was a significant (p⩽0.05) correlation between the reduction of intracellular ATP and increase in extracellular ATP following treatment of the cells with oregano oil. The reduction of intracellular ATP was even more important when essential oil was combined with irradiation, but irradiation of L. monocytogenes alone induced a significant decrease (p⩽0.05) of the internal ATP without affecting the external ATP.

Aims: The effects of gamma radiation on three heat shock proteins (Hsps) (GroEL, DnaK and GroES) synthesis in two Gram-negative (Escherichia coli and Salmonella serotype Typhimurium) and two Gram-positive (Staphylococcus aureus and Listeria monocytogenes) bacteria were investigated. Methods and Results: The bacterial strains were treated with three radiation doses to induce cell damage, to obtain a viable but nonculturable state, and to cause cell death. Western blot analysis and quantification of Hsps in bacteria were performed immediately after irradiation treatment. In the four foodborne pathogens, GroEL was strongly induced by gamma rays in a dose-dependent manner, confirming the involvement of this protein in the cellular response to the stress generated by ionizing radiation. In addition, it was found that E. coli exposed to gamma radiation showed a significantly induction of DnaK and GroES proteins when compared with nonirradiated bacteria, whereas a GroES slight induction and a DnaK inhibition were observed in Salm. Typhimurium. Conclusions: The gamma rays influence the synthesis of Hsps in foodborne pathogen in a way that critically depends on the radiation dose. Significance and Impact of the Study: The study of stress response to several radiation doses was undertaken to elucidate how bacteria can survive in harsh conditions and cope with gamma radiation used to control foodborne pathogens and to characterize their adaptative response to this treatment.

Aim: The aim of this study was to evaluate the effect of c radiation on the carotenoid content of two strains of the Enterobacteriaceae: Pantoea agglomerans. Methods and Results: Pantoea agglomerans strains ATCC 49174 and RL1 were used for this study. Successive radiation treatments were performed to study the radiotolerance. Total carotenoids were obtained by multiple extraction using chloroform ⁄ methanol (2 : 1), quantified by measuring the optical density at 453 nm and their antioxidant activity measured by a colorimetric method. The D10 studies were conducted using a UC-15A irradiator loaded with 60 Co. Bacterial counts from various dilutions were carried out after irradiation. Strain ATCC 49174 irradiated at 1 kGy produced 4AE3 times more carotenoids than the control, whereas carotenoid synthesis increased by 2AE9-fold in the strain RL1. However, there was no significant difference in the D10 values. Conclusion: Carotenoid increased production is influenced by c radiation but does not modify the tolerance to radiations. Significance and Impact of the Study: To our knowledge, this is the first study to demonstrate the effects of c radiation on carotenoid production levels.

Aims: To evaluate the efficacy of a biodegradable silage coating for the ability to protect timothy (Phleum pratensa) type silage against spoilage and its quality under natural conditions. Methods and Results: Triplicate mini-silos of silage were prepared for three treatments (1: uncoated; 2: coated with biodegradable coating and 3: sealed with plastic), two types of storage (unprotected or protected from rain) and 10 sampling times (0, 7, 14, 21, 28, 35, 42, 56, 63 and 70 days postensiling). Triplicate mini-silos were opened at each sampling time for microbiological (total aerobic bacteria, lactic acid bacteria, moulds and yeasts) and biochemical analyses [pH, dry matter (DM), water-soluble sugars (WSC), lactic (LA), acetic, propionic and butyric acids content]. The study showed that at day 70, counts of moulds and yeasts in silages protected against rain and coated with biodegradable coating were 5·98 log CFU g−1 when compared with 5·92 and 3·62 log CFU g−1 in samples from plastic-sealed silage and uncoated silage, respectively. The pH was low and stable pH (4·34) when compared with uncoated (7·17) and plastic sealed (8·34) silages (P 0·05). A DM, WSC and LA content of 421·7, 13·4 and 20·9 g kg−1 was, respectively, observed. For silage stored outdoors, a level of moulds and yeasts of 3·77 log CFU g−1 of silage was also observed in silages coated with biodegradable coating after 28 days of storage. A stable pH showing a mean value of 4 was also observed. The pH, DM, WSC and LA content were, respectively, 4·18, 341·1, 13·34 and 31·8 g kg−1 in these samples. After 70 days of storage, the level of moulds and yeasts on silage sealed with biodegradable coating was 7·73 log CFU g−1. A DM, WSC and LA content of 291·9, 5·56 and 10·0 g kg−1 was, respectively, observed. Conclusions: When compared with uncoated silage, the application of biodegradable coating can preserve the quality of silage for up to a month when exposed to rain and up to 70 days when protected from rain. Significance and Impact of the Study: Results emphasize the possibility of the use of a biodegradable coating as an alternative to plastic film for sealing horizontal bunker silos.

Twenty eight essential oils were evaluated for their antibacterial properties, against four pathogenic bacteria (Escherichia coli O157:H7, Listeria monocytogenes 2812 1/2a, Salmonella Typhimurium SL 1344 and Staphylococcus aureus). Essential oils were introduced into Brain Heart Infusion agar (BHI) (15 ml) at a concentration of 0.003%, 0.006%, 0.013%, 0.025%, 0.05%, 0.1%, 0.2%, 0.4% and 0.8% (vol/vol) to determine the minimum inhibitory concentration (MIC) and the maximal tolerated concentration (MTC) for each pathogen evaluated. Results showed that the most active essential oils against bacteria tested were Corydothymus capitatus, Cinnamomum cassia, Origanum heracleoticum, Satureja montana, and Cinnamomum verum (bark). These showed a MIC ⩽ 0.05% (vol/vol) for all bacteria tested. For the MTC, with the exception of S. Typhimurium and L. monocytogenes where a MTC of 0.025% (vol/vol) was observed in presence of Cinnamomum verum and Cinnamomum cassia, respectively, a MTC ⩽ 0.013% (vol/vol) was observed for all other bacteria and the three other most active essential oils. Three oils (Satureja hortensis, Thymus vulgaris carvacroliferum, Origanum compactum) showed a MIC ⩽ 0.1% (vol/vol) for all bacteria tested. Seven oils (Thymus vulgaris thymoliferum, Thymus serpyllum, Thymus satureioides, Cymbopogon martinii, Pimenta dioica, Cinnamomum verum (leaf), Eugenia caryophyllus) showed a lower antimicrobial activity showing a MIC ⩽ 0.4% (vol/vol) against the four bacteria tested. Finally, 13 essential oils were less active showing a MIC value ⩾ 0.8% (vol/vol) against at least one bacterium.

Antioxidant activities of pure chemicals and food additives were compared with that of herb extracts using a method based on the Fenton reaction for screening natural antioxidants. This method detects antioxidants classified as free radical terminators, that may compete with linoleic acid for scavenging OH radicals. Of the 39 products investigated, 19 were commercial products and 20 were aqueous and ethylic herb infusions. Commercial phenolic and flavonoid products, both hydrophilic and lipophilic, showed strong antioxidant activities, while indole, alkaloid and fs-cyclic products showed no antioxidant activity, as determined by this method. Aqueous infusions of all herbs showed antioxidant properties. Mild oregano, strong oregano, rosemary, sage and mint showed as strong antioxidant properties as pure commercial chemical and food additives, such as hydroquinone, rutin, phenidone, catechol, epicatechin, morin and BHA, in both aqueous and ethylic infusions. Also, the results suggest that, under the experimental conditions, the aqueous extractions of short duration yielded larger quantities of active compounds by reducing the degradation of their antioxidant properties.

The effects of gamma radiation and of oregano essential oil alone or in combination with radiation on murein composition of Listeria monocytogenes and on the intracellular and extracellular concentration of ATP were evaluated. The bacterial strain was treated with two radiation doses, 1.2 kGy to induce cell damage and 3.5 kGy to cause cell death. Oregano essential oil was used at 0.020 and 0.025% (wt/vol), which is the MIC. All treatments had a significant effect (P < or = 0.05) on the murein composition, although some muropeptides did not seem to be affected by the treatment. Each treatment influenced differently the relative percentage and number of muropeptides. There was a significant correlation (P < or = 0.05) between the reduction of intracellular ATP and increase in extracellular ATP, following treatment of the cells with oregano oil. The reduction of intracellular ATP was even more important when essential oil was combined with irradiation, but irradiation of L. monocytogenes alone induced a significant decrease (P < or = 0.05) of the internal ATP without affecting the external ATP. Transmission electron microscopic observation revealed that oregano oil and irradiation have an effect on cell wall structure.

Three commercial extracts of grape phenols (seeds, skin, whole) were used in this study. Each extract was divided by HPLC into five fractions of different polarities, and their free radical-scavenging activities were measured using the DPD ( N , N -diethyl- p -phenylenediamine) colorimetric method. Total phenol contents were determined using the Folin-Ciocalteu method to assess their contribution to the antiradical activity. The results showed that there was good correlation between total phenolic compound contents and free radical-scavenging activities of the different grape extracts. Moreover, the seed extract presented the most important free radical-scavenging properties (138 USP/mg extract), whereas the whole extract presented the lowest free radical-scavenging capacity (80.5 USP/mg extract). However, the free radical-scavenging properties, reported on the basis of content of phenolic compounds in each extract, showed that the free radical-scavenging activities of seed and whole extracts were not significantly different (171 versus 162 USP/mg phenol). In addition, free radical-scavenging activities of fractions from seed and skin extracts decreased as their polarities decreased.

The phenolic compounds in maple sap and syrup were extracted at different periods of the season and were separated to collect the glycosylated compounds and the aglycone compounds. The antioxidant and antiradical activities of each phenolic compound were studied using the thiobarbituric acid reactive substances (TBARS) assay and the N,N-diethyl-p-phenylenediamine (DPD) decoloration test to measure the free radical scavenging. The results showed that in general the phenolic compounds had a good antioxidant and antiradical properties. The glycosylated compounds from maple sap and maple syrup showed a better activity than the aglycones. The antimutagenic effects of each phenolic compounds from maple sap and syrup were also investigated as the inhibition of SOS induction by chemical agents in Salmonella typhimurium TA1535/pSK1002 containing the fusion gene umuC-lacZ. Induction of the SOS gene (umuC) expression was assayed by measuring accumulated β-galactosidase activity using a modified Umu test. The antimutagenic properties were studied per se and after metabolisation by S9 fraction. The results showed that an optimum of antimutagenic properties of the glycosylated metabolites phenolic compounds from sap and syrup was observed at 75% of the season for the sap and at 25% of the season for the syrup. A higher antimutagenic activity was observed at 25% and 100% of the season for aglycones present in syrup and at 75% of the season for aglycones present in sap.

Radiosensitization of Listeria monocytogenes was determined in the presence of trans-cinnamaldehyde, Spanish oregano, winter savory, and Chinese cinnamon on peeled minicarrots packed under air or under a modified atmosphere (60% O2, 30% CO2, and 10% N2). Samples were inoculated with L. monocytogenes HPB 2812 serovar 1/2a (106 CFU/g) and were coated separately with each active compound (0.5%, wt/wt) before being packaged under air or the modified atmosphere and irradiated at doses from 0.07 to 2.4 kGy. Results indicated that the bacterium was more resistant to irradiation under air in the absence of active compound. The dose required to reduce L. monocytogenes population by 1 log CFU (D10) was 0.36 kGy for samples packed under air and 0.17 kGy for those packed under the modified atmosphere. The active compounds evaluated in this study had an effect on the radiation sensitivity of L. monocytogenes on carrots. The most efficient compound was trans-cinnamaldehyde, where a mean 3.8-fold increase in relative radiation sensitivity was observed for both atmospheres compared with the control. The addition of winter savory and Chinese cinnamon produced a similar increase in relative radiation sensitivity but only when samples where packed under modified atmosphere conditions.

This study was carried out to evaluate the effects of gamma radiation alone or in combination with oregano essential oil on the murein composition of Escherichia coli O157:H7 and on the intracellular and extracellular concentrations of ATP. The bacterial strain was treated with three radiation doses: 0.4 kGy to induce cell damage, 1.1 kGy to obtain a viable but non-culturable state, and 1.3 kGy to cause cell death. Oregano essential oil was used at 0.006 and 0.025% (wt/vol), which is the MIC. All treatments had a significant effect (P < or = 0.05) on the murein composition, although some muropeptides did not seem to be affected by the treatment. Each treatment had a different effect on the relative percentage and number of muropeptides. There was a significant correlation (P < or = 0.05) between the decrease in intracellular ATP and the increase in extracellular ATP following treatment of the cells with oregano oil. The reduction of intracellular ATP was even more important when oregano oil was combined with irradiation, but irradiation alone at a high dose (< or = 1.1 kGy) significantly decreased (P < or = 0.05) the internal ATP without affecting the external ATP. Transmission electron microscopic examination revealed that oregano oil and irradiation have an effect on cell wall structure.

The effects of waxing, irradiation doses and storage on phenolic compounds and colour of irradiated oranges were investigated. Mature oranges (Citrus sinensis (L) Osbeck var Maroc late) waxed or unwaxed were treated with 0, 1 or 2 kGy radiation and stored up to 9 weeks at 20 °C and 40–50% RH. Colour of the oranges, total phenols and flavones in the peel were measured. Phenolic compounds increased with irradiation dose and storage time. Hue angle, L* value and chroma of the orange colour were more affected by waxing and storage time than the irradiation treatment. Changes in the phenolic compounds were linked with changes in the redness and saturation of the orange colour. Irradiation stimulated synthesis of flavones; waxing controlled changes induced by irradiation. These results may aid in maintaining the quality and safety of oranges during storage. Copyright © 2004 Society of Chemical Industry

The study evaluated the e•ects of waxing and irradiation dose on the essential oils in orange peel. Matureoranges (Maroc late) waxed or unwaxed were treated with 0–2 kGy radiation. Volatiles in the peel were extractedand analyzed by G.C. D-limonene was significantly lower (PE0.05) in waxed oranges; levels in samples treated with2 kGy were higher than those treated with 0 or 1 kGy. Linalool, methyl anthranilate and 3.7-dimethyl-2.6-octadienal decreased as the dose increased. The analysis of variance indicates that only linalool was influenced bypost-irradiation storage time. The level of this compound increased with storage time. 7 2000 Elsevier Science Ltd.All rights reserved. Keywords: Orange peel; Irradiation; Essential oils 1. IntroductionThe external tissues of citrus fruits are reported(Belli-Donini et al., 1974; Riov et al., 1972) to behighly susceptible to damage (pitting) upon irradiation.Pitting is the response of the flavedo cells in the exter-nal tissues of fruits to a high concentration of ethylene,phenolic compounds and terpenes; the irradiationtreatment is believed to stimulate biosynthesis of thesecompounds (Thomas, 1986; Riov et al., 1972). Theobjective of this study was to investigate the e•ects ofwaxing, irradiation dose and post-irradiation storagetime on the essential oils in Moroccan orange (M.late) peel.2. Materials and methods2.1. Raw materialsMature oranges (M. late) treated (waxed orunwaxed) were packed in 5 kg paper board flats withlids, then loaded into Royal Air Maroc air containersfor ambient air cargo shipment and transported fromCasablanca, Morocco, to Montre´al, Canada (CanadianIrradiation Centre, Laval, Canada), the same daywhere the irradiation treatment, storage and samplingfor chemical analysis were carried out. The wax con

Milk protein-based edible films containing 1.0% (w/v) oregano, 1.0% (w/v) pimento, or 1.0% oregano-pimento (1:1) essential oils mix were applied on beef muscle slices to control the growth of pathogenic bacteria and increase the shelf life during storage at 4 degrees C. Meat and film were periodically tested during 7 days for microbial and biochemical analysis. The lipid oxidation potential of meat was evaluated by the determination of thiobarbituric reactive substances (TBARS). The availability of phenolic compounds from essential oils was evaluated by the determination of total phenolic compounds present in the films during storage. Antioxidant properties of films during storage were also evaluated following a modified procedure of the N,N-diethyl-p-phenylenediamine colorimetric method. Oregano-based films stabilized lipid oxidation in beef muscle samples, whereas pimento-based films presented the highest antioxidant activity. The application of bioactive films on meat surfaces containing 10(3) colony-forming units/cm2 of Escherichia coli O157:H7 or Pseudomonas spp. showed that film containing oregano was the most effective against both bacteria, whereas film containing pimento oils seems to be the least effective against these two bacteria. A 0.95 log reduction of Pseudomonas spp. level, as compared to samples without film, was observed at the end of storage in the presence of films containing oregano extracts. A 1.12 log reduction of E. coli O157:H7 level was noted in samples coated with oregano-based films.

The effect of a hydrophobic biodegradable coating on the conservation of silage was evaluated in comparison with unsealed silage and silage covered with a polyethylene (plastic). Silage samples were subjected to biochemical analysis (pH, dry matter, water-soluble sugars, ammoniacal nitrogen, lactic acid) and microbiological analysis (total aerobes, lactic acid bacteria, moulds and yeasts) during 135 days of storage. Silage covered with the biodegradable coating had a constant pH value of 4.79 and was preserved against spoilage until day 120, whereas the pH of unsealed silage increased during the first 6 days to a value of 8.22. After 2 months of storage, silage covered with the biodegradable coating had a lower dry matter content, higher water-soluble sugar content and higher lactic acid concentration than unsealed silage. During storage the population of total aerobes was lower in silage covered with the biodegradable coating than in silage covered with plastic. Furthermore, silage covered with the biodegradable coating had a stable content of aerobic micro-organisms. The biodegradable-coated silage showed a growth of lactic acid bacteria similar to that of silage covered with plastic. Only silage covered with the biodegradable coating had a low initial content of moulds and yeasts. Air infiltration was present throughout the storage period in the plastic and biodegradable coating treatments and was linked with the degradation of silage in both cases. However, the biodegradable coating significantly (P ≤ 0.05) increased the period of silage conservation compared with that of uncoated silage. Copyright © 2004 Society of Chemical Industry

Entire fresh chicken legs were subjected to three pretreatments (packaged in air; packaged under vacuum; or marinated in natural plant extracts and packaged in air) followed by irradiation (0, 3, or 5 kGy). The control and irradiated chicken legs were stored at 4°C and analyzed for FA composition and sensory quality at predetermined intervals. Irradiation dose had a significant (P 0.05) in the flavor and oder intensity of cooked irradiated chicken legs and their nonirradiated equivalents.

Spice extracts under the form of essential oils (Eos) were tested for their efficiency to increase the relative bacterial radiosensitivity (RBR) of Listeria monocytogenes, Escherichia coli and Salmonella typhi in culture media under different atmospheric conditions. The selected Eos were tested for their ability to reduce the dose necessary to eliminate E. coli and S. typhi in medium fat ground beef (23% fat) and Listeria in ready-to-eat carrots when packed under air or under atmosphere rich in oxygen (MAP). Results have demonstrated that depending of the compound added and the combined treatment used, the RBR increased from 2 to 4 times. In order to evaluate the industrial feasibility, EOs were added in ground beef at a concentration which does not affect the taste and treated at a dose of 1.5 kGy. The content of total mesophilic aerobic, E. coli, Salmonella, total coliform, lactic acid bacteria, and Pseudomonas was determined during 28 days. The results showed that the combined treatment (radiation and EOs) can eliminate Salmonella and E. coli when done under air. When done under MAP, Pseudomonas could be eliminated and a shelf life of more than 28 days was observed. An active edible coating containing EOs was also developed and sprayed on ready-to-eat carrots before radiation treatment and Listeria was evaluated. A complete inhibition of Listeria was obtained at a dose of 0.5 kGy when applied under MAP. Our results have shown that the combination of an edible coating, MAP, and radiation can be used to maintain the safety of meat and vegetables.

International audience; The antimicrobial effect of cranberry juice and of three cranberry extracts (water-soluble (E1) and apolar phenolic compounds (E2), and anthocyanins (E3)) was investigated against seven bacterial strains (Enterococcus faecium resistant to vancomycin (ERV), Escherichia coli O157:H7 EDL 933, Escherichia coli ATCC 25922, Listeria monocytogenes HPB 2812, Pseudomonas aeruginosa ATCC 15442, Salmonella Typhimurium SL1344, and Staphylococcus aureus ATCC 29213). Each cranberry sample was analyzed to determine the minimum inhibitory concentration (MIC) and the maximal tolerated concentration (MTC) at neutral pH. The results, reported in μg phenol/mL, indicated that all the bacterial strains, both Gram-positive and Gram-negative, were selectively inhibited by the cranberry phenolic compounds. The extract rich in water-soluble phenolic compounds caused the most important growth inhibitions. The bacteria ERV, and to a lesser degree, P. aeruginosa, S. aureus and E. coli ATCC 25922, were the most sensitive to the antimicrobial activity of extract E1. The growth of P. aeruginosa and E. coli ATCC was also affected by the presence of the anthocyanin-rich cranberry extract E3, although the observed antibacterial effect was not as important as with extract E1. In general, L. monocytogenes, E. coli O157:H7 and S. Typhimurium were the most resistant to the antibacterial activity of the cranberry extracts. Within 30 min of exposure with pure neutralized cranberry juice, L. monocytogenes and ERV were completely inactivated.

International audience; Cranberries are healthy fruit that contribute color, flavor, nutritional value, and functionality. They are one of only three fruits native to America. Over the past decade, public interest for the North American cranberry (Vaccinium macrocarpon) has been rising with reports of their potential health benefits linked to the numerous phytochemicals present in the fruit--the anthocyanins, the flavonols, the flavan-3-ols, the proanthocyanidins, and the phenolic acid derivatives. The presence of these phytochemicals appears to be responsible for the cranberry property of preventing many diseases and infections, including cardiovascular diseases, various cancers, and infections involving the urinary tract, dental health, and Helicobacter pylori-induced stomach ulcers and cancers. Recent years have seen important breakthroughs in our understanding of the mechanisms through which these compounds exert their beneficial biological effects, yet these remain to be scientifically substantiated. In this paper these characteristics, as well as the antioxidant, radical scavenging, antibacterial, antimutagen, and anticarcinogen properties of cranberry major bioactive compounds are explained.

International audience; The study was carried out to evaluate the effects of gamma-irradiation alone or in combination with oregano essential oil on murein composition of Staphylococcus aureus and on the intracellular and extracellular concentration of ATP. The bacterial strain was treated with 3 irradiation doses: 1.2 kGy to induce cell damage, 2.9 kGy to obtain a viable but nonculturable state, and 3.5 kGy to cause cell death. Oregano essential oil was used at 0.010% and 0.013% (w/v), which is the minimum inhibitory concentration (MIC). All treatments had a significant effect (P < or = 0.05) on the murein composition, although some muropeptides did not seem to be affected by the treatment. Each treatment influenced differently the relative percentage and number of muropeptides. There was a significant (P < or = 0.05) correlation between the reduction of intracellular ATP and increase in extracellular ATP following treatment of the cells with oregano oil. The reduction of intracellular ATP was even more important when essential oil was combined with irradiation. Also, irradiation alone of S. aureus induced a significant decrease (P < or = 0.05) of the internal ATP and a significant increase (P < or = 0.05) of the external ATP. However, no significant difference (P > 0.05) was observed in ATP concentrations between different radiation doses. Transmission electron microscopic observation revealed that oregano oil and irradiation have an effect on cell wall structure.

Aims: The aim of this study was to evaluate the effect of γ-irradiation on the fatty acids (FA) and muropeptides content of two strains of an Enterobacteriacea: Pantoea agglomerans. Methods and Results: Pantoea agglomerans strains ATCC 49174 and RL1 isolated from irradiated carrots were used for this study. Radiation treatments (1 and 3·5 kGy) were performed to study the radiotolerance. Total lipids were obtained by multiple extractions using methanol/chloroform (2 : 1) and were quantified by GC. Muropeptides were purified by successive enzymatic digestions and analysed using a reverse phase C18 column in high performance liquid chromatography. A significant (P ≤ 0·05) modification of the bacterial wall was noticed for the membrane FA composition and the muropeptides. Conclusion: Effects of irradiation on the bacterial membrane are noticeable and could play an important role on the cellular response and ability to survive this harsh environment. Significance and Impact of the Study: To our knowledge, it is the first study to demonstrate the effects of ionizing irradiation on the modification of the FA and one of the few to confirm its effects on the muropeptides of the peptidoglycan.

Bologna and ham slices (300 of each) were inoculated with Salmonella Typhimurium or Listeria monocytogenes at 10(3) CFU/cm(2). Alginate-based edible films that had been immersed in a 2 or 20% (wt/vol) CaC12 solution and contained 1% (wt/ vol) essential oils of Spanish oregano (O; Corydothymus capitatus), Chinese cinnamon (C; Cinnamomum cassia), or winter savory (S; Satureja montana) were then applied to slices to control pathogen growth. On bologna, C-based films pretreated with 20% CaC12 were the most effective against the growth of Salmonella Typhimurium and L. monocytogenes. L. monocytogenes was the more sensitive bacterium to O-, C-, and S-based films. L. monocytogenes concentrations were below the detection level (

Alginate-based edible films containing 1% (wt/vol) essential oils of Spanish oregano, Chinese cinnamon, or savory were immersed in 2% (wt/vol) or 20% (wt/vol) CaCl2 solution and then applied to beef muscle slices to control the growth of Escherichia coli O157:H7 and Salmonella Typhimurium. Whole beef muscle surfaces were inoculated with one of these strains at 10(3) CFU/cm2. During the 5 days of storage, samples of meat were obtained periodically for microbiological analysis. The availability of active compounds from essential oils present in films was evaluated by determination of total phenolic compounds for oregano- and savory-based films and of total aldehydes for cinnamon-based films during storage. After 5 days of storage, films containing oregano or cinnamon essential oils were the most effective against Salmonella Typhimurium regardless of the type of pretreatment used (2 or 20% CaCl2). During the same period, meat inoculated with E. coli O157:H7 and coated with films treated with 2% CaCl2 had significantly fewer bacteria (P < or = 0.05) when oregano-based films were used than when cinnamon- and savory-based films were used. The E. coli O157:H7 concentration was higher at the end of the storage period when films were pretreated with 20% CaCl2. Evaluation of the active compounds in films revealed that availability in oregano- and savory-based films was significantly more important (P < or = 0.05) than that in cinnamon-based films regardless of the type of pretreatment used (2 or 20% CaCl2). At the end of storage, release rates of 40, 60, and 77% were noted in oregano-, savory-, and cinnamon-based films in 2% CaCl2 and rates of 65, 62, and 90% were noted in the same films in 20% CaCl2.

The mechanism of the antimicrobial action of Spanish oregano (Corydothymus capitatus), Chinese cinnamon (Cinnamomum cassia), and savory (Satureja montana) essential oils against cell membranes and walls of bacteria was studied by the measurement of the intracellular pH and ATP concentration, the release of cell constituents, and the electronic microscopy observations of the cells when these essential oils at their MICs were in contact with Escherichia coli O157:H7 and Listeria monocytogenes. E. coli O157:H7 and L. monocytogenes, two pathogenic foodborne bacteria, were used as gram-negative and gram-positive bacterial models, respectively. Treatment with these essential oils at their MICs affected the membrane integrity of bacteria and induced depletion of the intracellular ATP concentration. Spanish oregano and savory essential oils, however, induced more depletion than Chinese cinnamon oil. An increase of the extracellular ATP concentration was observed only when Spanish oregano and savory oils were in contact with E. coli O157:H7 and L. monocytogenes. Also, a significantly higher (P < or = 0.05) cell constituent release was observed in the supernatant when E. coli O157:H7 and L. monocytogenes cells were treated with Chinese cinnamon and Spanish oregano oils. Chinese cinnamon oil was more effective to reduce significantly the intracellular pH of E. coli O157:H7, whereas Chinese cinnamon and Spanish oregano decreased more significantly the intracellular pH of L. monocytogenes. Electronic microscopy observations revealed that the cell membrane of both treated bacteria was significantly damaged. These results suggest that the cytoplasmic membrane is involved in the toxic action of essential oils.

The objective of this study was to evaluate the effect of an edible antimicrobial coating combined with modified atmosphere (MA) packaging (60% O2, 30% CO2, and 10% N2) and gamma irradiation on peeled minicarrots inoculated with Listeria innocua. Carrots were inoculated with L. innocua (10(3) CFU/g) and then coated with an antimicrobial coating based on calcium caseinate containing trans-cinnamaldehyde. The same formulation without trans-cinnamaldehyde was used as an inactive coating. Coated and uncoated carrots were packed under the MA or under air, irradiated at 0.25 or 0.5 kGy, and stored at 4 +/- 1 degrees C for 21 days. Samples were evaluated periodically for enumeration of L. innocua. Unirradiated carrots stored under air had the highest concentrations of L. innocua after 21 days of storage: 2.23 CFU/g in the uncoated samples and 2.26 CFU/ g in samples coated with the inactive coating. These results suggest that the inactive coating did not have any antimicrobial effect against L. innocua. However, the addition of the antimicrobial coating resulted in a 1.29-log reduction in the concentration of L. innocua in carrots packed under air after 21 days of storage and a 1.08-log reduction in carrots packed under MA after 7 days of storage. After 7 days of storage, no L. innocua was detected in samples treated at 0.5 kGy under air or in samples treated at 0.25 kGy under MA. A complete inhibition of L. innocua was also observed during all storage periods in uncoated and coated samples treated at 0.5 kGy under MA. These results indicate that the combination of irradiation and MA conditions play an important role in the radiosensitization of L. innocua.

The inhibitory effect of 60 different essential oils was evaluated on a Pseudomonas putida strain of meat origin, associated with meat spoilage. Essential oils were tested at concentrations from 0.003 to 0.8% (wt/vol) to determine minimum inhibitory and maximal tolerated concentrations (MIC and MTC, respectively) using an agar medium culture. Of the 60 samples tested, Corydothymus capitatus essential oil was the most active showing a MIC of 0.025% and a MTC of 0.06%. Seven essential oils (Cinnamomum cassia, Origanum compactum, Origanum heracleoticum, Satureja hortensis, Satureja montana, Thymus vulgaris carvacroliferum, Thymus vulgaris thymoliferum) have shown a strong antimicrobial activity against P. putida with a MIC of 0.05% and a MTC ranging from 0.013% to 0.025%. Ten other oils (Cinnamomum verum (leaf and bark), Eugenia caryophyllus, Cymbopogon martinii var. motia, Cymbopogon nardus, Melaleuca linariifolia, Origanum majorana, Pimenta dioica, Thymus satureoides, Thymus serpyllum) showed a high antimicrobial activity showing a MIC ranging from 0.1% to 0.4%, while the remaining were less active showing a MIC⩾0.8%.

The objective of this study was to evaluate the effect of an edible coating combined with modified atmosphere (MA; 60% O2, 30% CO2, and 10% N2) packaging and gamma irradiation on the microbiological stability and physicochemical quality of minimally processed carrots. A coating based on calcium caseinate and whey protein isolates was used. Coated and uncoated peeled minicarrots were packed under the MA or air (78.1% N2, 20.9% O2, and 0.036% CO2), irradiated at 0.5 or 1 kGy, and stored at 4 +/- 1 degrees C for 21 days. Samples were evaluated periodically for aerobic plates counts (APCs) and physicochemical properties (firmness, white discoloration, and whiteness index). Gamma irradiation did not significantly affect the physicochemical properties of the carrots (P0.05). Microbiological analysis revealed that for uncoated carrots irradiation at 0.5 and 1 kGy under air and MA reduced the APCs by 3.5 and 4 log CFU/g and by 4 and 4.5 log CFU/g, respectively. For coated carrots, irradiation at 0.5 and 1 kGy under air and MA reduced the APCs by 4 and 4.5 log CFU/g and by 3 and 4.25 log CFU/g, respectively. The coating was able to protect carrots against dehydration during storage under air. Coating and irradiation at 1 kGy were also able to protect carrot firmness during storage under air. MA packaging retarded whitening of uncoated carrots but had a detrimental effect on firmness. The edible coating used in this study did not significantly inhibit (P0.05) microbial growth on carrots.

Chicken legs were subjected to two pretreatments (packaged in air or marinated in natural plant extracts and then packaged in air) followed by irradiation (0, 3, or 5 kGy). The control and irradiated chicken legs were stored at 4 degrees C and underwent microbial analysis (mesophilic aerobic plate counts and Salmonella detection) and sensory evaluation at predetermined intervals. Microbial analysis indicated that irradiation had a significant effect (Por = 0.05) on the mesophilic aerobic plate counts of the poultry. For each treatment, the bacterial growth decreased with an increase of irradiation dose. The marinade had an additive effect with irradiation in reducing bacterial growth and controlling proliferation during storage at 4 +/- 1 degree C. No Salmonella was observed until day 12 in marinated chicken irradiated at 3 kGy and for all experiments with chicken legs stored under air or marinated at 5 kGy. However, Salmonella was found in chicken legs irradiated at 3 kGy in air and in nonirradiated samples. The sensory evaluation indicated a significant (Por = 0.05) difference in odor and flavor intensities between the irradiated chicken at 5 kGy and the control. No significant difference was found (P0.05) between the marinated chicken irradiated at 5 kGy and the control.