• Bovine whey peptides transit the intestinal barrier to reduce oxidative stress in muscle cells

      Corrochano, Alberto R.; Ferraretto, Anita; Arranz, Elena; Stuknytė, Milda; Bottani, Michela; O'Connor, Paula M.; Kelly, Philip; De Noni, Ivano; Buckin, Vitaly; Giblin, Linda; et al. (Elsevier, 2019-03-06)
      Health benefits are routinely attributed to whey proteins, their hydrolysates and peptides based on in vitro chemical and cellular assays. The objective of this study was to track the fate of whey proteins through the upper gastrointestinal tract, their uptake across the intestinal barrier and then assess the physiological impact to downstream target cells. Simulated gastrointestinal digestion (SGID) released a selection of whey peptides some of which were transported across a Caco-2/HT-29 intestinal barrier, inhibited free radical formation in muscle and liver cells. In addition, SGID of β-lactoglobulin resulted in the highest concentration of free amino acids (176 nM) arriving on the basolateral side of the co-culture with notable levels of branched chain and sulphur-containing amino acids. In vitro results indicate that consumption of whey proteins will deliver bioactive peptides to target cells.
    • Brans of the roller-milled barley fractions rich in polyphenols and health-promoting lipophilic molecules

      Gangopadhyay, Nirupama; Harrison, Sabine M; Brunton, Nigel P; Hidalgo-Ruiz, José L; Gallagher, Eimear; Rai, Dilip K.; Department of Agriculture, Food and the Marine; 11/SF/317 (Elsevier, 2018-09-01)
      Three different roller-milled fractions namely bran, middlings, and flour of five commonly grown Irish barley varieties were investigated for the presence of β-glucan, polyphenols, and health-promoting lipophilic molecules. β-glucan was predominantly located in barley middlings. Polyphenols, as indicated by total phenolic content and the antioxidant activities, were abundant in the outermost bran fractions of barley. Similarly the health-promoting lipophilic molecules including phytosterols, unsaturated fatty acids, and tocols were most abundant in the barley bran fraction. However, the distribution of individual polyphenols and lipophilic compounds varied within the grain; for example ferulic acid and procyainidin C were not detected in flour fraction. Principal component analysis (PCA) clearly indicated a higher distribution of most bioactive molecules in bran as compared to middlings and flour fractions. The PCA also established possible correlations between the five barley varieties and their fractions based on their clustering in the plot.
    • Breast Milk, a Source of Beneficial Microbes and Associated Benefits for Infant Health

      Lyons, Katríona E.; Ryan, C. Anthony; Dempsey, Eugene M.; Ross, R Paul; STANTON, CATHERINE; Department of Agriculture, Food and the Marine; Science Foundation Ireland; 15F721 (MDPI AG, 2020-04-09)
      Human breast milk is considered the optimum feeding regime for newborn infants due to its ability to provide complete nutrition and many bioactive health factors. Breast feeding is associated with improved infant health and immune development, less incidences of gastrointestinal disease and lower mortality rates than formula fed infants. As well as providing fundamental nutrients to the growing infant, breast milk is a source of commensal bacteria which further enhance infant health by preventing pathogen adhesion and promoting gut colonisation of beneficial microbes. While breast milk was initially considered a sterile fluid and microbes isolated were considered contaminants, it is now widely accepted that breast milk is home to its own unique microbiome. The origins of bacteria in breast milk have been subject to much debate, however, the possibility of an entero-mammary pathway allowing for transfer of microbes from maternal gut to the mammary gland is one potential pathway. Human milk derived strains can be regarded as potential probiotics; therefore, many studies have focused on isolating strains from milk for subsequent use in infant health and nutrition markets. This review aims to discuss mammary gland development in preparation for lactation as well as explore the microbial composition and origins of the human milk microbiota with a focus on probiotic development.
    • Comparison of antioxidant activities of bovine whey proteins before and after simulated gastrointestinal digestion

      Corrochano, Alberto R.; Sariçay, Yunus; Arranz, Elena; Kelly, Philip; Buckin, Vitaly; Giblin, Linda; Department of Agriculture, Food and the Marine; Teagasc Walsh Fellowship Programme; 13 F 354-WheyGSH (Elsevier, 2018-10-24)
      Oxidative stress caused by free radicals has been implicated in several human disorders. Dietary antioxidants can help the body to counteract those reactive species and reduce oxidative stress. Antioxidant activity is one of the multiple health-promoting attributes assigned to bovine whey products. The present study investigated whether this activity was retained during upper gut transit using a static simulated in vitro gastrointestinal digestion (SGID) model. The capacity to scavenge free radicals and reduce ferric ion of whey protein isolate (WPI), individual whey proteins, and hydrolysates pre- and post-SGID were measured and compared using various antioxidant assays. In addition, the free AA released from individual protein fractions in physiological gut conditions were characterized. Our results indicated that the antioxidant activity of WPI after exposure to the harsh conditions of the upper gut significantly increased compared with intact WPI. From an antioxidant bioactivity viewpoint, this exposure negates the need for prior hydrolysis of WPI. The whey protein α-lactalbumin showed the highest antioxidant properties post-SGID (oxygen radical absorbance capacity = 1,825.94 ± 50.21 μmol of Trolox equivalents/g of powder) of the 4 major whey proteins tested with the release of the highest amount of the antioxidant AA tryptophan, 6.955 μmol of tryptophan/g of protein. Therefore, α-lactalbumin should be the preferred whey protein in food formulations to boost antioxidant defenses.
    • Complete Genome Sequence of Clostridium estertheticum DSM 8809, a Microbe Identified in Spoiled Vacuum Packed Beef

      Yu, Zhongyi; Gunn, Lynda; Brennan, Evan; Reid, Rachael; Wall, Patrick G.; O Gaora, Peadar; Hurley, Daniel; Bolton, Declan; Fanning, Seamus; Department of Agriculture, Food and the Marine (Frontiers, 2016-11-11)
      Blown pack spoilage (BPS) is a major issue for the beef industry. Etiological agents of BPS involve members of a group of Clostridium species, including Clostridium estertheticum which has the ability to produce gas, mostly carbon dioxide, under anaerobic psychotrophic growth conditions. This spore-forming bacterium grows slowly under laboratory conditions, and it can take up to 3 months to produce a workable culture. These characteristics have limited the study of this commercially challenging bacterium. Consequently information on this bacterium is limited and no effective controls are currently available to confidently detect and manage this production risk. In this study the complete genome of C. estertheticum DSM 8809 was determined by SMRT® sequencing. The genome consists of a circular chromosome of 4.7 Mbp along with a single plasmid carrying a potential tellurite resistance gene tehB and a Tn3-like resolvase-encoding gene tnpR. The genome sequence was searched for central metabolic pathways that would support its biochemical profile and several enzymes contributing to this phenotype were identified. Several putative antibiotic/biocide/metal resistance-encoding genes and virulence factors were also identified in the genome, a feature that requires further research. The availability of the genome sequence will provide a basic blueprint from which to develop valuable biomarkers that could support and improve the detection and control of this bacterium along the beef production chain.
    • Complete Genome Sequence of Mannheimia varigena Isolated from Bovine Milk

      McCabe, Matthew; Esnault, Gaelle; Murray, Gerard; Earley, Bernadette; Cormican, Paul; Department of Agriculture, Food and the Marine; 11/S/131 (American Society for Microbiology, 2019-02-21)
      Mannheimia varigena is a pathogen of cattle that has been isolated from diseased lung and udder. There are currently complete genome sequences for 4 M. varigena isolates, all from lungs of cattle in the United States. We report a complete genome sequence of M. varigena isolated from bovine milk in Ireland.
    • Complexes between linoleate and native or aggregated β-lactoglobulin: Interaction parameters and in vitro cytotoxic effect.

      Le Maux, Solene; Bouhallab, Said; Giblin, Linda; Brodkorb, Andre; Croguennec, Thomas; Department of Agriculture, Food and the Marine; Teagasc Walsh Fellowship Programme; Irish Research Council for Science, Engineering and Technology; 08/RD/TMFRC/650 (Elsevier, 2013-11)
      Iron is essential for human health, but it sometimes causes an unpleasant taste, rusty colour and a decrease in the stability of food products. Previously, we found that ethanol-treated yeast (ETY) cells could remove iron from wine and juice, and reduce the fishy aftertaste induced by iron in wine–seafood pairings. However, the mechanism of iron sorption by ETY cells is undefined; thus, there is no indicator that can be used to estimate the iron sorption capacity of these cells. In this study, we showed that cell wall components are not mainly associated with iron sorption by investigating ETY cells with the cell wall removed. Moreover, plasma membrane permeability was correlated with the iron sorbing capacity of the cells. Microscopic analysis showed that iron accumulated within ETY cells. Proteinase-treated ETY cells had no iron sorbing capacity. On the basis of these results, we conclude that intracellular proteins are involved in iron sorption by ETY cells.
    • The Composition of Human Milk and Infant Faecal Microbiota Over the First Three Months of Life: A Pilot Study

      Murphy, Kiera; Curley, David; O’Callaghan, Tom F.; O’Shea, Carol A; Dempsey, Eugene; O'Toole, Paul W.; Ross, R Paul; Ryan, C. Anthony; STANTON, CATHERINE; Department of Agriculture, Food and the Marine; et al. (Nature, 2017-01-17)
      Human milk contains a diverse array of bioactives and is also a source of bacteria for the developing infant gut. The aim of this study was to characterize the bacterial communities in human milk and infant faeces over the first 3 months of life, in 10 mother-infant pairs. The presence of viable Bifidobacterium and Lactobacillus in human milk was also evaluated. MiSeq sequencing revealed a large diversity of the human milk microbiota, identifying over 207 bacterial genera in milk samples. The phyla Proteobacteria and Firmicutes and the genera Pseudomonas, Staphylococcus and Streptococcus were the predominant bacterial groups. A core of 12 genera represented 81% of the microbiota relative abundance in milk samples at week 1, 3 and 6, decreasing to 73% at week 12. Genera shared between infant faeces and human milk samples accounted for 70–88% of the total relative abundance in infant faecal samples, supporting the hypothesis of vertical transfer of bacteria from milk to the infant gut. In addition, identical strains of Bifidobacterium breve and Lactobacillus plantarum were isolated from the milk and faeces of one mother-infant pair. Vertical transfer of bacteria via breastfeeding may contribute to the initial establishment of the microbiota in the developing infant intestine.
    • Current Status and Future Prospects of Marine Natural Products (MNPs) as Antimicrobials

      Choudhary, Alka; Naughton, Lynn; Montánchez, Itxaso; Dobson, Alan; Rai, Dilip K.; Department of Agriculture, Food and the Marine; 11/F/009 (MDPI, 2017-08-28)
      The marine environment is a rich source of chemically diverse, biologically active natural products, and serves as an invaluable resource in the ongoing search for novel antimicrobial compounds. Recent advances in extraction and isolation techniques, and in state-of-the-art technologies involved in organic synthesis and chemical structure elucidation, have accelerated the numbers of antimicrobial molecules originating from the ocean moving into clinical trials. The chemical diversity associated with these marine-derived molecules is immense, varying from simple linear peptides and fatty acids to complex alkaloids, terpenes and polyketides, etc. Such an array of structurally distinct molecules performs functionally diverse biological activities against many pathogenic bacteria and fungi, making marine-derived natural products valuable commodities, particularly in the current age of antimicrobial resistance. In this review, we have highlighted several marine-derived natural products (and their synthetic derivatives), which have gained recognition as effective antimicrobial agents over the past five years (2012–2017). These natural products have been categorized based on their chemical structures and the structure-activity mediated relationships of some of these bioactive molecules have been discussed. Finally, we have provided an insight into how genome mining efforts are likely to expedite the discovery of novel antimicrobial compounds.
    • Current Status and Future Prospects of Marine Natural Products (MNPs) as Antimicrobials

      Choudhary, Alka; Naughton, Lynn; Montánchez, Itxaso; Dobson, Alan; Rai, Dilip; Department of Agriculture, Food and the Marine; FIRM 11/F/009 (MDPI AG, 2017-08-28)
      The marine environment is a rich source of chemically diverse, biologically active natural products, and serves as an invaluable resource in the ongoing search for novel antimicrobial compounds. Recent advances in extraction and isolation techniques, and in state-of-the-art technologies involved in organic synthesis and chemical structure elucidation, have accelerated the numbers of antimicrobial molecules originating from the ocean moving into clinical trials. The chemical diversity associated with these marine-derived molecules is immense, varying from simple linear peptides and fatty acids to complex alkaloids, terpenes and polyketides, etc. Such an array of structurally distinct molecules performs functionally diverse biological activities against many pathogenic bacteria and fungi, making marine-derived natural products valuable commodities, particularly in the current age of antimicrobial resistance. In this review, we have highlighted several marine-derived natural products (and their synthetic derivatives), which have gained recognition as effective antimicrobial agents over the past five years (2012–2017). These natural products have been categorized based on their chemical structures and the structure-activity mediated relationships of some of these bioactive molecules have been discussed. Finally, we have provided an insight into how genome mining efforts are likely to expedite the discovery of novel antimicrobial compounds.
    • The cytotoxicity of fatty acid/α-lactalbumin complexes depends on the amount and type of fatty acid

      Brinkman, Christel Rothe; Brodkorb, Andre; Thiel, Steffen; Kehoe, Joseph James; Department of Agriculture, Food and the Marine; 08RDTMFRC650 (Wiley, 17/04/2013)
      Complexes of the milk protein, α-lactalbumin, and the fatty acid, oleic acid, have previously been shown to be cytotoxic. Complexes of α-lactalbumin and five different fatty acids (vaccenic, linoleic, palmitoleic, stearic, and elaidic acid) were prepared and compared to those formed with oleic acid. All complexes were cytotoxic to human promyelocytic leukemia-derived (HL-60) cells but to different degrees depending on the fatty acid. The amount of fatty acid per α-lactalbumin molecule was found to correlate with the cytotoxicity; the higher the number of fatty acids per protein, the more cytotoxic the complex. Importantly, all the tested fatty acids were also found to be cytotoxic on their own in a concentration dependent manner. The cytotoxic effect of complexes between α-lactalbumin and linoleic acid, vaccenic acid, or oleic acid was further investigated using flow cytometry and found to induce cell death resembling apoptosis on Jurkat cells. Practical applications: Cytotoxic complexes of α-lactalbumin and several different fatty acids could be produced. The cytotoxicity of all the variants is similar to that previously determined for α-lactalbumin/oleic acid complexes.
    • Detection and characterisation of Complement protein activity in bovine milk by bactericidal sequestration assay

      Maye, Susan; STANTON, CATHERINE; Fitzgerald, Gerald F; Kelly, Philip; Teagasc Walsh Fellowship Programme; Department of Agriculture, Food and the Marine (Cambridge University Press for the Institute of Food Research and the Hannah Research Institute, 29/06/2015)
      While the Complement protein system in human milk is well characterised, there is little information on its presence and activity in bovine milk. Complement forms part of the innate immune system, hence the importance of its contribution during milk ingestion to the overall defences of the neonate. A bactericidal sequestration assay, featuring a Complement sensitive strain, Escherichia coli 0111, originally used to characterise Complement activity in human milk was successfully applied to freshly drawn bovine milk samples, thus, providing an opportunity to compare Complement activities in both human and bovine milks. Although not identical in response, the levels of Complement activity in bovine milk were found to be closely comparable with that of human milk. Differential counts of Esch. coli 0111 after 2 h incubation were 6·20 and 6·06 log CFU/ml, for raw bovine and human milks, respectively – the lower value representing a stronger Complement response. Exposing bovine milk to a range of thermal treatments e.g. 42, 45, 65, 72, 85 or 95 °C for 10 min, progressively inhibited Complement activity by increasing temperature, thus confirming the heat labile nature of this immune protein system. Low level Complement activity was found, however, in 65 and 72 °C heat treated samples and in retailed pasteurised milk which highlights the outer limit to which high temperature, short time (HTST) industrial thermal processes should be applied if retention of activity is a priority. Concentration of Complement in the fat phase was evident following cream separation, and this was also reflected in the further loss of activity recorded in low fat variants of retailed pasteurised milk. Laboratory-based churning of the cream during simulated buttermaking generated an aqueous (buttermilk) phase with higher levels of Complement activity than the fat phase, thus pointing to a likely association with the milk fat globule membrane (MFGM) layer.
    • Detection and Enumeration of Spore-Forming Bacteria in Powdered Dairy Products

      McHugh, Aoife; Feehily, Conor; Hill, Colin; Cotter, Paul D.; Department of Agriculture, Food and the Marine (Frontiers, 2017-01-31)
      With the abolition of milk quotas in the European Union in 2015, several member states including Ireland, Luxembourg, and Belgium have seen year on year bi-monthly milk deliveries to dairies increase by up to 35%. Milk production has also increased outside of Europe in the past number of years. Unsurprisingly, there has been a corresponding increased focus on the production of dried milk products for improved shelf life. These powders are used in a wide variety of products, including confectionery, infant formula, sports dietary supplements and supplements for health recovery. To ensure quality and safety standards in the dairy sector, strict controls are in place with respect to the acceptable quantity and species of microorganisms present in these products. A particular emphasis on spore-forming bacteria is necessary due to their inherent ability to survive extreme processing conditions. Traditional microbiological detection methods used in industry have limitations in terms of time, efficiency, accuracy, and sensitivity. The following review will explore the common spore-forming bacterial contaminants of milk powders, will review the guidelines with respect to the acceptable limits of these microorganisms and will provide an insight into recent advances in methods for detecting these microbes. The various advantages and limitations with respect to the application of these diagnostics approaches for dairy food will be provided. It is anticipated that the optimization and application of these methods in appropriate ways can ensure that the enhanced pressures associated with increased production will not result in any lessening of safety and quality standards.
    • Early Gut Microbiota Perturbations Following Intrapartum Antibiotic Prophylaxis to Prevent Group B Streptococcal Disease

      Mazzola, Giuseppe; Murphy, Kiera; Ross, R Paul; Di Gioia, Diana; Biavati, Bruno; Corvaglia, Luigi T.; Faldella, Giacomo; STANTON, CATHERINE; Department of Agriculture, Food and the Marine; European Union; et al. (PLOS, 22/06/2016)
      The faecal microbiota composition of infants born to mothers receiving intrapartum antibiotic prophylaxis with ampicillin against group B Streptococcus was compared with that of control infants, at day 7 and 30 of life. Recruited newborns were both exclusive breastfed and mixed fed, in order to also study the effect of dietary factors on the microbiota composition. Massive parallel sequencing of the V3-V4 region of the 16S rRNA gene and qPCR analysis were performed. Antibiotic prophylaxis caused the most marked changes on the microbiota in breastfed infants, mainly resulting in a higher relative abundance of Enterobacteriaceae, compared with control infants (52% vs. 14%, p = 0.044) and mixed-fed infants (52% vs. 16%, p = 0.13 NS) at day 7 and in a lower bacterial diversity compared to mixed-fed infants and controls. Bifidobacteria were also particularly vulnerable and abundances were reduced in breastfed (p = 0.001) and mixed-fed antibiotic treated groups compared to non-treated groups. Reductions in bifidobacteria in antibiotic treated infants were also confirmed by qPCR. By day 30, the bifidobacterial population recovered and abundances significantly increased in both breastfed (p = 0.025) and mixed-fed (p = 0.013) antibiotic treated groups, whereas Enterobacteriaceae abundances remained highest in the breastfed antibiotic treated group (44%), compared with control infants (16%) and mixed-fed antibiotic treated group (28%). This study has therefore demonstrated the short term consequences of maternal intrapartum antibiotic prophylaxis on the infant faecal microbial population, particularly in that of breastfed infants.
    • Effect of different forage types on the volatile and sensory properties of bovine milk

      Faulkner, Hope; O'Callaghan, Tom; McAuliffe, Stephen; Hennessy, Deirdre; STANTON, CATHERINE; O'Sullivan, Maurice G.; Kerry, Joseph P.; Kilcawley, Kieran; Department of Agriculture, Food and the Marine; 13SN401 (Elsevier, 2017-12-08)
      The effect of 3 diets (grass, grass/clover, and total mixed ration) on the volatile and sensory properties of bovine milk was assessed over an entire lactation season. Little evidence was found of direct transfer of terpenes into raw milk from the different diets, and it is likely that the monocultures of ryegrass used with and without white clover were factors as these contained very few terpenes. Evidence of direct transfer of nonterpene volatiles from forage to the subsequent raw milks was probable; however, differences in the protein carbohydrate availability and digestion in the rumen appeared to have a greater contribution to volatile profiles. Pasteurization significantly altered the volatile profiles of all milks. A direct link between the milk fatty acid content, forage, and volatile products of lipid oxidation was also evident and differences in fatty acid content of milk due to forage may also have influenced the viscosity perception of milk. Irish sensory assessors preferred pasteurized milk produced from grass-fed cows, with least preference from milk produced from total mixed ration diets. β-Carotene content was significantly higher in milks derived from grass or grass/clover and appears to have directly influenced color perception. Toluene and p-cresol are both degradation products of β-carotene and along with β-carotene were identified as potential biomarkers for milk derived from pasture. The only correlation that appeared to influence the flavor of milk as determined using ranked descriptive analysis was p-cresol. P-Cresol appears to be responsible for the barnyard aroma of milk and is also likely derived from the deamination and decarboxylation of tryptophan and tyrosine due to the higher levels of available protein in the grass and grass/clover diets. The highest levels of p-cresol were in the grass/clover diets and are likely due to the degradation of the isoflavone formononetin in the rumen, which is present in white clover swards.
    • Effect of Drying Methods on the Steroidal Alkaloid Content of Potato Peels, Shoots and Berries

      Brunton, Nigel; Hossain, Mohammad Billal; Rai, Dilip K.; Department of Agriculture, Food and the Marine; 11F/050 (MDPI, 2016-03-25)
      The present study has found that dried potato samples yielded significantly higher levels of steroidal alkaloids such as α-solanine and α-chaconine than the corresponding fresh samples, as determined by the UPLC-MS/MS technique. Among the drying techniques used, air drying had the highest effect on steroidal alkaloid contents, followed by freeze drying and vacuum oven drying. There was no significant difference between the freeze dried and vacuum oven dried samples in their α-chaconine contents. However, freeze dried potato shoots and berries had significantly higher α-solanine contents (825 µg/g dry weight (DW) in shoots and 2453 µg/g DW in berries) than the vacuum oven dried ones (325 µg/g dry weight (DW) in shoots and 2080 µg/g DW in berries). The kinetics of steroidal alkaloid contents of potato shoots during air drying were monitored over a period of 21 days. Both α-solanine and α-chaconine content increased to their maximum values, 875 µg/g DW and 3385 µg/g DW, respectively, after 7 days of drying. The steroidal alkaloid contents of the shoots decreased significantly at day 9, and then remained unchanged until day 21. In line with the potato shoots, air dried potato tuber peels also had higher steroidal alkaloid content than the freeze dried and vacuum oven dried samples. However, a significant decrease of steroidal alkaloid content was observed in air dried potato berries, possibly due to degradation during slicing of the whole berries prior to air drying. Remarkable variation in steroidal alkaloid contents among different tissue types of potato plants was observed with the potato flowers having the highest content.
    • The Effect of High Pressure Processing on Antioxidant Activity of Irish Potato Cultivars

      Tsikrika, Konstantina; Rai, Dilip K.; Department of Agriculture, Food and the Marine; 17/F/299 (MDPI, 2019-04-16)
      The effect of High Pressure Processing (HPP) on Irish potato cultivars’ antioxidant activity (AOA) was examined. High Pressure Processing at 600 MPa for 3 min was applied to two coloured (Rooster and Kerr’s Pink) and two white (Saxon and Gemson) Irish potato varieties. Antioxidant activity was assayed spectrophotometrically by ferric reducing antioxidant power and diphenyl-1-picrylhydrazyl methods. No statistically significant (p ≥ 0.05) change in antioxidant activity was observed in both the AOA methods irrespective of the HPP treatments, although a slight increase in the activity was noted in the majority of the HPP treated samples. This implies that HPP treatment has little role in improving the functional qualities, and can be tailored to improve the quality and safety of the commonly consumed potatoes.
    • Effectiveness of current hygiene practices on minimization of Listeria monocytogenes in different mushroom production‐related environments

      Pennone, Vincenzo; Dygico, Kenneth Lyonel; Coffey, Aidan; Gahan, Cormac G.M.; Grogan, Helen; McAuliffe, Olivia; Burgess, Catherine M.; Jordan, Kieran; Department of Agriculture, Food and the Marine; 14/F/881 (Wiley, 2020-05-20)
      Background: The commercial production of Agaricus bisporus is a three stage process: 1) production of compost, also called “substrate”; 2) production of casing soil; and 3) production of the mushrooms. Hygiene practices are undertaken at each stage: pasteurization of the substrate, hygiene practices applied during the production of casing soil, postharvest steam cookout, and disinfection at the mushroom production facilities. However, despite these measures, foodborne pathogens, including Listeria monocytogenes, are reported in the mushroom production environment. In this work, the presence of L. monocytogenes was evaluated before and after the application of hygiene practices at each stage of mushroom production with swabs, samples of substrate, casing, and spent mushroom growing substrates. Results: L. monocytogenes was not detected in any casing or substrate sample by enumeration according to BS EN ISO 11290-2:1998. Analysis of the substrate showed that L. monocytogenes was absent in 10 Phase II samples following pasteurization, but was then present in 40% of 10 Phase III samples. At the casing production facility, 31% of 59 samples were positive. Hygiene improvements were applied, and after four sampling occasions, 22% of 37 samples were positive, but no statistically significant difference was observed (p > .05). At mushroom production facilities, the steam cookout process inactivated L. monocytogenes in the spent growth substrate, but 13% of 15 floor swabs at Company 1 and 19% of 16 floor swabs at Company 2, taken after disinfection, were positive. Conclusion: These results showed the possibility of L. monocytogenes recontamination of Phase III substrate, cross-contamination at the casing production stage and possible survival after postharvest hygiene practices at the mushroom growing facilities. This information will support the development of targeted measures to minimize L. monocytogenes in the mushroom industry.
    • Enrichment and Assessment of the Contributions of the Major Polyphenols to the Total Antioxidant Activity of Onion Extracts: A Fractionation by Flash Chromatography Approach

      Hossain, Mohammad Billal; Lebelle, Justine; Birsan, Rares; Rai, Dilip K.; Department of Agriculture, Food and the Marine; FIRM 06/NITAFRC/6 (MDPI AG, 2018-11-27)
      The present study extensively fractionated crude red onion extract in order to identify the polyphenols which contributed most in the total antioxidant capacity of the onion extract using a flash chromatography system. The flash separations produced 70 fractions which were tested for their total phenol content, total flavonoid content, and antioxidant capacities as measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Out of these 70 fractions, four fractions which were representatives of the four major peaks of the flash chromatograms, were further analysed for their constituent polyphenols using liquid chromatography tandem mass spectrometry (LC-MS/MS). The main contributor of onion antioxidant capacity is quercetin glycoside followed by quercetin aglycone although quercetin aglycone had higher antioxidant capacity than its glycosidic counterparts. High abundance of quercetin glycosides such as quercetin-3,4′-diglucoside and quercetin-4′-glucoside had compensated for their relatively low antioxidant capacities. A Higher degree of glycosylation resulted in lower antioxidant capacity. The fractionation approach also contributed in enrichment of the onion antioxidant polyphenols. A >9 folds enrichment was possible by discarding the early fractions (fractions 1–15) which contained the main bulk of the extracts, predominantly sugars.
    • Enrichment and Assessment of the Contributions of the Major Polyphenols to the Total Antioxidant Activity of Onion Extracts: A Fractionation by Flash Chromatography Approach

      Hossain, Mohammad Billal; Lebelle, Justine; Birsan, Rares; Rai, Dilip K.; Department of Agriculture, Food and the Marine; 06/NITAFRC/6 (MDPI, 2018-11-27)
      The present study extensively fractionated crude red onion extract in order to identify the polyphenols which contributed most in the total antioxidant capacity of the onion extract using a flash chromatography system. The flash separations produced 70 fractions which were tested for their total phenol content, total flavonoid content, and antioxidant capacities as measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Out of these 70 fractions, four fractions which were representatives of the four major peaks of the flash chromatograms, were further analysed for their constituent polyphenols using liquid chromatography tandem mass spectrometry (LC-MS/MS). The main contributor of onion antioxidant capacity is quercetin glycoside followed by quercetin aglycone although quercetin aglycone had higher antioxidant capacity than its glycosidic counterparts. High abundance of quercetin glycosides such as quercetin-3,4′-diglucoside and quercetin-4′-glucoside had compensated for their relatively low antioxidant capacities. A Higher degree of glycosylation resulted in lower antioxidant capacity. The fractionation approach also contributed in enrichment of the onion antioxidant polyphenols. A >9 folds enrichment was possible by discarding the early fractions (fractions 1–15) which contained the main bulk of the extracts, predominantly sugars.