Alfalfa Sprouts Research Articles

Sound waves increases the ascorbic acid content of alfalfa sprouts by affecting the expression of ascorbic acid biosynthesis-related genes

Previous studies have shown that sound wave treatment can affect the expression of plant genes and improve the growth. So, we investigated the ability of sound waves to increase AsA (l-ascorbic acid) content in alfalfa (Medicago sativa) sprouts in this study. Sprouts were exposed to a range of sound wave frequencies for two 1-h periods per day for various numbers of days. Most sound wave treated sprouts had a higher AsA content than untreated sprouts. In addition, the activity level of superoxide dismutase, an enzyme with potent antioxidative properties, was increased in sound wave-treated sprouts. The AsA content varied in response to sound wave treatment. Most processing conditions, including 500 and 1000 Hz, increased AsA content by 24–50%; however, some treatment conditions caused reduced AsA content during sprout growth. Furthermore, AsA content during sprout storage was increased by most sound wave treatment conditions, with 13–36% increases observed following 800 and 1000 Hz sound wave treatments compared to untreated sprouts. To investigate the mechanisms underlying changes in AsA content, we analyzed the expression levels of AsA biosynthesis-related genes. We found that several genes, including VTC1, VTC2, VTC4, GME, L-GalDH, GLDH, MDHAR, and DHAR1, displayed differential expression in response to sound wave treatment. Therefore, sound wave treatment may be a viable method for increasing the nutritional contents of sprouted vegetables.

Development of a novel multiplexed qPCR and Pyrosequencing method for the detection of human pathogenic yersiniae

The purpose of this study was to develop a novel and robust molecular assay for the detection of human pathogenic yersiniae (i.e. Yersinia enterocolitica, Y. pseudotuberculosis and Y. pestis) in complex food samples. The assay combines multiplexed real-time PCR (qPCR) and Pyrosequencing for detecting and differentiating human pathogenic yersiniae with high confidence through sequence based confirmation. The assay demonstrated 100% specificity and inclusivity when tested against a panel of 14 Y. enterocolitica, 22 Y. pestis, 24 Y. pseudotuberculosis and a diverse selection of 17 other non-Yersinia bacteria. Pyrosequencing reads ranged from 28 to 40bp in length and had 94–100% sequence identity to the correct species in the GenBank nr database. Microbial enrichments of 48 ready-to-eat foods collected in the Greater Toronto Area from March 2014 to May 2014, including 46 fresh sprout and 2 salad products, were then tested using the assay. All samples were negative for Y. pestis and Y. pseudotuberculosis. Both salads (n=2) and 35% of sprout products (n=46) including 7.1% of alfalfa sprouts (n=14), 81% of bean sprouts (n=16), 12% of mixed sprouts (n=8) tested positive for Y. enterocolitica which was not detected in broccoli sprouts (n=5), onion sprouts (n=1), and pea sprouts (n=2). Cycle thresholds (Ct) of positive samples for Y. enterocolitica were between 23.0 and 37.9 suggesting post enrichment concentrations of approximately 1×102 to 1×106Y. enterocolitica per 1mL of enriched broth. An internal amplification control which was coamplified with targets revealed PCR inhibition in five samples which was resolved following a one in ten dilution. Pyrosequencing of qPCR amplicons suggests monoclonality and revealed a single nucleotide polymorphism that is present in Y. enterocolitica biotype 1A suggesting low pathogenicity of the detected strains. This study is the first to combine Pyrosequencing and qPCR for the detection of human pathogenic yersiniae and is applicable to a broad range of complex samples including ready-to-eat food samples.

Attachment and Biofilm Formation by Selected Strains of Salmonella enterica and Entrohemorrhagic Escherichia coli of Fresh Produce Origin.

This study compared the abilities of selected Salmonella enterica and enterohemorrhagic Escherichia coli (EHEC) strains of fresh produce origin to form biofilms on polystyrene surface and to attach to alfalfa and bean sprouts. Each of the 7 S. enterica and 4 EHEC inocula (2 mL; 107 CFU/mL) was placed in 6 different broths in 24-well polystyrene tissue culture plates at 28 °C for 1 to 7 d. Developed biofilms were quantified using the crystal violet binding assay. In a separate experiment, alfalfa and mung bean sprouts (5 g) were exposed to 25 mL inocula (107 CFU/mL) of S. enterica or EHEC at 22 °C for 2 h with shaking at 40 rpm. Contaminated sprouts were thoroughly rinsed and homogenized in 0.1% peptone water, and bacteria attached to sprouts were enumerated. Biofilm mass accumulated on polystyrene surface increased with incubation time (P < 0.05). Among the microbiological media used, LB no salt (NaCl) broth better supported biofilm development (P < 0.05). Two EHEC strains formed more biofilms than the Salmonella and other two EHEC strains (P < 0.05). However, more Salmonella cells (5.66 log CFU/g) attached to sprouts than EHEC cells (3.46 log CFU/g). Both Salmonella and EHEC attached in higher numbers to mung bean, than alfalfa, sprouts (P < 0.05).

Colorimetric and Electrochemical Bacteria Detection Using Printed Paper- and Transparency-Based Analytic Devices.

The development of transparency-based electrochemical and paper-based colorimetric analytic detection platforms is presented as complementary methods for food and waterborne bacteria detection from a single assay. Escherichia coli and Enterococcus species, both indicators of fecal contamination, were detected using substrates specific to enzymes produced by each species. β-galactosidase (β-gal) and β-glucuronidase (β-glucur) are both produced by E. coli, while β-glucosidase (β-gluco) is produced by Enterococcus spp. Substrates used produced either p-nitrophenol (PNP), o-nitrophenol (ONP), or p-aminophenol (PAP) as products. Electrochemical detection using stencil-printed carbon electrodes (SPCEs) was found to provide optimal performance on inexpensive and disposable transparency film platforms. Using SPCEs, detection limits for electrochemically active substrates, PNP, ONP, and PAP were determined to be 1.1, 2.8, and 0.5 μM, respectively. A colorimetric paper-based well plate system was developed from a simple cardboard box and smart phone for the detection of PNP and ONP. Colorimetric detection limits were determined to be 81 μM and 119 μM for ONP and PNP respectively. While colorimetric detection methods gave higher detection limits than electrochemical detection, both methods provided similar times to positive bacteria detection. Low concentrations (101 CFU/mL) of pathogenic and nonpathogenic E. coli isolates and (100 CFU/mL) E. faecalis and E. faecium strains were detected within 4 and 8 h of pre-enrichment. Alfalfa sprout and lagoon water samples served as model food and water samples, and while water samples did not test positive, sprout samples did test positive within 4 h of pre-enrichment. Positive detection of inoculated (2.3 × 102 and 3.1 × 101 CFU/mL or g of E. coli and E. faecium, respectively) sprout and water samples tested positive within 4 and 12 h of pre-enrichment, respectively.

Fresh preservation of alfalfa sprouts and mushroom slices by soaking with thymol and resveratrol solutions.

The preservation of fresh produce served as salads through soaking with solutions containing naturally occurring phenolic ingredients is of merit. For a primary assay, thymol and resveratrol at 0–500 ppm were prepared and used to inhibit growth and survival of Escherichia coli and Staphylococcus aureus. Thymol and resveratrol exhibited potent inhibitory activities against the growth of both bacteria. For S. aureus, cells treated with thymol at 250 ppm or resveratrol at 500 ppm, the durations to achieve 3 log reduction (3LR) were 40 and 20 min, respectively. When the cells were treated with thymol combined with resveratrol, both at 250 ppm, the 3LR value was achieved in under 5 min. Synergistic antibacterial activity between thymol and resveratrol was apparent. The antibacterial and known health‐enhancing activities of resveratrol are of interest.

Consumption of Broccoli Sprouts Attenuates Intracellular P38 Map Kinase and Reactive Oxygen Species Pro-Inflammatory Activation in Human Leukocytes: A Randomised- Controlled Trial

Dietary consumption of green vegetables has a protective association with reduction in cardiovascular diseases. The thiocyanate compound sulforaphane, which is obtained from green vegetables, induces antioxidant genes and can protect against pro-inflammatory cellular activation. Our objective was to investigate the influence of sulforaphane on leukocyte pro-inflammatory activation and assess the impact of a sulforaphane-rich diet on leukocyte activation in vivo. Healthy human volunteers were randomised to consume either broccoli sprout homogenates (BSH) rich in sulforaphane or alfalfa sprout homogenates (ASH) as controls in a double-blind crossover trial. Blood was sampled prior to and then at 1 h, 6 h and 24 h post-homogenate consumption and analysed by flow cytometry for intracellular markers of leukocyte activation, reactive oxygen species (ROS), p38 mitogen activated protein (MAP) kinase phosphorylation and p65 nuclear factor kappa B (NF-κB) phosphorylation. Plasma levels of sulforaphane were determined by LC-MS methods. Six participants were recruited into the study. Plasma concentrations of sulforaphane were 30 ng/ml at one hour following BSH and undetectable following ASH consumption. In the control ASH group, ROS activation and p38 MAP kinase phosphorylation were enhanced one hour following consumption. This increase was attenuated in the BSH group (ROS, p<0.02: p38, p<0.001 comparison between groups). We conclude that ingestion of sulforaphane-rich homogenate can protect against pro-inflammatory activation in circulating leukocytes by attenuation of constitutive ROS and p38 MAP kinase.

Decontamination of alfalfa and mung bean sprouts by ultrasound and aqueous chlorine dioxide

The antimicrobial effect of ultrasound, aqueous chlorine dioxide (ClO2) and the combination of both treatments was assessed on Escherchia coli and Salmonella enteritidis inoculated on alfalfa and mung bean sprouts were performed for 5 min. This work presents the first approach regarding the using of the previously mentioned technologies on the decontamination of inoculated sprouts. Ultrasound (26 kHz, 90 μm, 200 W) process was able to reduce by 1.40 ± 0.40 and 1.89 ± 0.51 log CFU/g Salmonella and by 1.06 ± 0.32 and 1.23 ± 0.40 log CFU/g of E. coli on alfalfa and mung bean sprouts, respectively. ClO2 (3 ppm) reduced the population of the studied bacteria in similar levels (≈1.5 log CFU/g) both in alfalfa and mung bean sprouts. However, ClO2 treatment was more effective than the ultrasound process in terms of E. coli and Salmonella total inactivation (i.e., water and sprouts) both in alfalfa and mung bean sprouts. Additionally, an additive effect was observed in the reduction of both E. coli and Salmonella and the total inactivation when ultrasound was combined with ClO2 in all tested food products.

Legume seeds and cereal grains' capacity to accumulate iron while sprouting in order to obtain food fortificant.

Prepared sprouts, after culturing in a medium with an increased iron concentration, could become a beneficial food iron fortificant. However, the efficient iron accumulation depends on the plants genus, species and/or varieties. The aim of the study was to indicate the seeds or grains which accumulate iron most efficiently during the sprouting process. Alfalfa, lentil, lupine and soybean seeds as well as wheat grains were sprouted in abiotic stress conditions induced by the excess of iron(II) in culture media. The tolerance of these plants to iron concentration and its accumulation in the material obtained (with FAAS method) were analyzed. The smallest tolerance was noted for lentil seeds and wheat grains. Other plants developed in 25 mM solution of FeSO4. The highest accumulation of iron was observed in alfalfa sprouts. However, lupine and soybean seeds are the most recommended raw material for the production of the sprouts on an industrial scale.

Rapid Identification of Shiga Toxin–Producing Escherichia coli O Serogroups from Fresh Produce and Raw Milk Enrichment Cultures by Luminex Bead–Based Suspension Array

The U.S. Food and Drug Administration's Bacteriological Analytical Manual (BAM) Chapter 4a describes a Luminex microbead-based suspension array used to screen colonies for 11 clinically relevant Shiga toxin-producing Escherichia coli (STEC) serogroups: O26, O45, O91, O103, O104, O111, O113, O121, O128, O145, and O157. We evaluated the usefulness of this method to identify STEC-positive enrichment samples before agar plating. Twelve E. coli strains were added to three types of fresh produce (bagged baby spinach, alfalfa sprouts, and cilantro) at levels near the detection limit of the test. A subset of these strains (six O serogroups) was similarly evaluated in raw milk. For comparison, portions of each of the 168 enrichment cultures were analyzed for serogroup by a real-time PCR assay and a Bio-Plex 200 assay with the bead-based suspensions. No false-positive results were obtained. Of the 112 samples with a reported cycle threshold (CT) value, 101 undiluted, diluted, or extracted enrichment cultures also produced ratios above 5.0 in the Bio-Plex assay. When PCR CT values approached or were greater than 35, Bio-Plex detection became less reliable. Using undiluted or extracted enrichment cultures resulted in a significantly larger number of positive results. With the same enrichment material prepared for real-time PCR analysis as described in the BAM Chapter 4a, the STEC microbead-based suspension array can accurately screen food enrichment cultures.

Potential transfer of extended spectrum β-lactamase encoding gene, blashv18 gene, between Klebsiella pneumoniae in raw foods

This study investigated the transfer frequency of the extended-spectrum β-lactamase-encoding gene (blaSHV18) among Klebsiella pneumoniae in tryptic soy broth (TSB), pasteurized milk, unpasteurized milk, alfalfa sprouts and chopped lettuce at defined temperatures. All transconjugants were characterized phenotypically and genotypically. KP04ΔKM and KP08ΔKM isolated from seed sprouts and KP342 were used as recipients in mating experiments with K. pneumoniae ATCC 700603 serving as the donor. In mating experiments, no transconjugants were detected at 4 °C in liquid media or chopped lettuce, but detected in all media tested at 15 °C, 24 °C, and 37 °C. At 24 °C, the transfer of blaSHV18 gene occurred more frequently in alfalfa sprouts (5.15E-04 transconjugants per recipient) and chopped lettuce (3.85E-05) than liquid media (1.08E-05). On chopped lettuce, transconjugants were not detected at day 1 post-mating at 15 °C, but observed on day 2 (1.43E-05). Transconjugants carried the blaSHV18 gene transferred from the donor and the virulence gene harbored by recipient. More importantly, a class 1 integrase gene and resistance to tetracycline, trimethoprim/sulfamethoxazole were co-transferred during mating. These quantitative results suggest that fresh produce exposed to temperature abuse may serve as a competent vehicle for the spread of gene encoding for antibiotic resistance, having a potential negative impact on human health.

A Randomized Controlled Trial of the Effect of Broccoli Sprouts on Antioxidant Gene Expression and Airway Inflammation in Asthmatics

Broccoli sprouts (BS) are the richest source of sulforaphane (SFN), which is a potent inducer of phase II enzymes, which play a critical role in preventing oxidative stress (OS) and inflammation. The objective of this study was to determine if ingestion of whole BS improves airway inflammatory and physiologic outcomes, and OS in adults with asthma and allergic sensitization to an indoor allergen. The study is a double-blind, placebo-controlled, randomized trial to compare the effects of BS with placebo (alfalfa sprouts [AS]) on airway inflammation and markers of OS. Forty adults (aged 18-50 years) were randomized to eat either (a) 100 g of BS daily or (b) 100 g of AS daily for 3 days. Fractional exhaled nitric oxide (FENO), forced expiratory volume 1, nasal epithelial and PBMC gene expression, inflammatory and OS biomarkers, and symptoms were assessed both before and after ingestion of the sprouts. The primary outcome variable was the change in FENO. Secondary outcome measures included rhinitis and asthma symptoms, lung function, and OS and inflammatory biomarkers. BS ingestion for 3 consecutive days did not reduce FENO, despite resulting in a marked increase in serum SFN concentrations (21 vs 22 parts per billion, P= .76). Furthermore, BS consumption did not induce cytoprotective antioxidant genes in either PBMCs or nasal epithelial cells, reduce OS and inflammatory markers, or improve lung function. Ingestion of whole BS for 3 days does not appear to improve eosinophilic pulmonary inflammation, inflammatory and OS biomarkers, or clinical features of asthma among atopic adults with asthma despite resulting in a marked increase in serum SFN levels.

A green-analytical chemistry method for agrochemical-residue analysis in vegetables

Ten agrochemicals, including fungicides, insecticides, herbicides and a plant growth regulator, were quantified at part per billion levels in complex matrices using a green-analytical chemistry (GAC) method. Liquid chromatography with dual UV/diode array (DAD) and fluorescence (FLD) detections was carried out in a single run, and the second-order DAD-elution time and FLD-elution time data obtained were treated with MCR-ALS (multivariate curve resolution/alternating least-squares) algorithm. In this way, while analytes are measured through their more appropriate (absorbance and/or fluorescence) signals, chemometric treatment of the corresponding matrices allows the resolution of total or partial overlapped bands, and to overcome the presence of interferences in real samples. In this work, FLD-elution time second-order data were obtained for the first time at two excitation wavelengths, improving the sensitivity of fluorescent analytes. The approach was successfully applied to in land cultivated vegetables, including mushroom, lettuce, alfalfa sprout, cucumber, and celery.

Adaptation and Validation of E-Probe Diagnostic Nucleic Acid Analysis for Detection of Escherichia coli O157:H7 in Metagenomic Data from Complex Food Matrices

The Centers for Disease Control and Prevention recently emphasized the need for enhanced technologies to use in investigations of outbreaks of foodborne illnesses. To address this need, e-probe diagnostic nucleic acid analysis (EDNA) was adapted and validated as a tool for the rapid, effective identification and characterization of multiple pathogens in a food matrix. In EDNA, unassembled next generation sequencing data sets from food sample metagenomes are queried using pathogen-specific sequences known as electronic probes (e-probes). In this study, the query of mock sequence databases demonstrated the potential of EDNA for the detection of foodborne pathogens. The method was then validated using next generation sequencing data sets created by sequencing the metagenome of alfalfa sprouts inoculated with Escherichia coli O157:H7. Nonspecific hits in the negative control sample indicated the need for additional filtration of the e-probes to enhance specificity. There was no significant difference in the ability of an e-probe to detect the target pathogen based upon the length of the probe set oligonucleotides. The results from the queries of the sample database using E. coli e-probe sets were significantly different from those obtained using random decoy probe sets and exhibited 100% precision. The results support the use of EDNA as a rapid response methodology in foodborne outbreaks and investigations for establishing comprehensive microbial profiles of complex food samples.

Alfalfa and flax sprouts supplementation enriches the content of bioactive compounds and lowers the cholesterol in hen egg

The effect of dietary supplementation with flax and alfalfa sprouts (40 g/d) on bioactive compounds and cholesterol contents of hen's egg was examined. Thirty White Leghorn hens, 26 weeks of age, were fed, for 66 days, three diets that included control (standard diet – C), standard diet + alfalfa sprouts (A), and standard diet + flax sprouts (F). Productive performance of hens was recorded daily. The cholesterol content of plasma and yolk, and the presence of bioactive compounds in the egg, were also analysed. Supplementation of flax and alfalfa sprouts reduced plasma and egg cholesterol probably due to the synergy between different compounds of the sprouts (polyunsaturated fatty acids - PUFAs, lignans, isoflavones and sterols). Eggs from A and F groups also had higher contents of n-3 PUFA, vitamins (α-tocopherol, α-, γ-tocotrienol, retinol), carotenes (β-carotene, lutein, zeaxanthin) and phytoestrogens (daidzein, equol, isolariciresinol) than eggs from the C group.

Effect of Broccoli Sprouts and Live Attenuated Influenza Virus on Peripheral Blood Natural Killer Cells: A Randomized, Double-Blind Study.

Enhancing antiviral host defense responses through nutritional supplementation would be an attractive strategy in the fight against influenza. Using inoculation with live attenuated influenza virus (LAIV) as an infection model, we have recently shown that ingestion of sulforaphane-containing broccoli sprout homogenates (BSH) reduces markers of viral load in the nose. To investigate the systemic effects of short-term BSH supplementation in the context of LAIV-inoculation, we examined peripheral blood immune cell populations in non-smoking subjects from this study, with a particular focus on NK cells. We carried out a randomized, double-blinded, placebo-controlled study measuring the effects of BSH (N = 13) or placebo (alfalfa sprout homogenate, ASH; N = 16) on peripheral blood mononuclear cell responses to a standard nasal vaccine dose of LAIV in healthy volunteers. Blood was drawn prior to (day-1) and post (day2, day21) LAIV inoculation and analyzed for neutrophils, monocytes, macrophages, T cells, NKT cells, and NK cells. In addition, NK cells were enriched, stimulated, and assessed for surface markers, intracellular markers, and cytotoxic potential by flow cytometry. Overall, LAIV significantly reduced NKT (day2 and day21) and T cell (day2) populations. LAIV decreased NK cell CD56 and CD158b expression, while significantly increasing CD16 expression and cytotoxic potential (on day2). BSH supplementation further increased LAIV-induced granzyme B production (day2) in NK cells compared to ASH and in the BSH group granzyme B levels appeared to be negatively associated with influenza RNA levels in nasal lavage fluid cells. We conclude that nasal influenza infection may induce complex changes in peripheral blood NK cell activation, and that BSH increases virus-induced peripheral blood NK cell granzyme B production, an effect that may be important for enhanced antiviral defense responses.Trial Registration: ClinicalTrials.gov NCT01269723

The effects of Mg enrichment of vegetable sprouts on Mg concentration, yield and ROS generation.

Two-thirds of the world's population do not consume the recommended amount of Mg, hence the demand for the production of Mg-enriched plants. Sprouts represent promising targets for enrichment. This study evaluated the effects of enriching broccoli, radish, alfalfa and mung bean sprouts with Mg (50-300 mg L(-1) ) on (i) the concentration of Mg and other ions, (ii) biomass accumulation, (iii) levels of reactive oxygen species (ROS), and (iv) the activity/content of enzymatic and non-enzymatic components of antioxidative systems. Enrichment of sprouts with Mg led to a significant increase in Mg concentration, especially in alfalfa (increase of 23-152 %), without depletion of other ions. A higher Mg concentration had a minor effect on biomass accumulation, but increased, often significantly, ROS generation and affected enzymatic and non-enzymatic antioxidative systems. The level of O2 (•-) increased most in broccoli, by 59-158%, while OH(•) increased most in radish, by 200-350%. Enrichment of sprouts with Mg is possible, but attention must be paid to elevated ROS levels in food. Mung bean sprouts are best suited to enrichment as they make a considerable contribution to the daily supplementation of Mg, at still low levels of ROS in enriched plants. © 2015 Society of Chemical Industry.

Development of prototypes of bioactive packaging materials based on immobilized bacteriophages for control of growth of bacterial pathogens in foods

Due to lack of adequate control methods to prevent contamination in fresh produce and growing consumer demand for natural products, the use of bacteriophages has emerged as a promising approach to enhance safety of these foods. This study sought to control Listeria monocytogenes in cantaloupes and RTE meat and Escherichia coli O104:H4 in alfalfa seeds and sprouts under different storage conditions by using specific lytic bacteriophage cocktails applied either free or immobilized. Bacteriophage cocktails were introduced into prototypes of packaging materials using different techniques: i) immobilizing on positively charged modified cellulose membranes, ii) impregnating paper with bacteriophage suspension, and iii) encapsulating in alginate beads followed by application of beads onto the paper. Phage-treated and non-treated samples were stored for various times and at temperatures of 4°C, 12°C or 25°C. In cantaloupe, when free phage cocktail was added, L. monocytogenes counts dropped below the detection limit of the plating technique (<1logCFU/g) after 5days of storage at both 4°C and 12°C. However, at 25°C, counts below the detection limit were observed after 3 and 6h and a 2-logCFU/g reduction in cell numbers was seen after 24h. For the immobilized Listeria phage cocktail, around 1-logCFU/g reduction in the Listeria count was observed by the end of the storage period for all tested storage temperatures. For the alfalfa seeds and sprouts, regardless of the type of phage application technique (spraying of free phage suspension, bringing in contact with bacteriophage-based materials (paper coated with encapsulated bacteriophage or impregnated with bacteriophage suspension)), the count of E. coli O104:H4 was below the detection limit (<1logCFU/g) after 1h in seeds and about a 1-log cycle reduction in E. coli count was observed on the germinated sprouts by day 5. In ready-to-eat (RTE) meat, LISTEX™ P100, a commercial phage product, was able to significantly reduce the growth of L. monocytogenes at both storage temperatures, 4°C and 10°C, for 25days regardless of bacteriophage application format (immobilized or non-immobilized (free)).In conclusion, the developed phage-based materials demonstrated significant antimicrobial effect, when applied to the artificially contaminated foods, and can be used as prototypes for developing bioactive antimicrobial packaging materials capable of enhancing the safety of fresh produce and RTE meat.

Growth and quality of sprouts of six vegetables cultivated under different light intensity and quality

Vegetable sprouts (alfalfa, broccoli, clover, kohlrabi, radish, and red radish) were cultivated under three monochromatic light regimes (red, green, and blue) with five different light intensities (0, 12.5, 25, 50, and 100 µmol·m−2·s−1) to investigate the effects of light intensity and quality on the growth and total phenolic content of the vegetable sprouts. The light quality and intensity had a direct effect on hypocotyl elongation in vegetable sprouts. Increasing blue light intensity enhanced suppression of hypocotyl elongation in all of the vegetable sprouts. Red light also reduced hypocotyl length in alfalfa and clover sprouts comparing those grown in darkness. The fresh weight of broccoli and radish sprouts markedly increased when red light intensity was 100 µmol·m−2·s−1; however, light use efficiency (LUE) decreased with increasing light intensity. Total phenolic content was reduced by increasing red light intensity in alfalfa and red radish sprouts.

Inactivation of Human Norovirus and Its Surrogates on Alfalfa Seeds by Aqueous Ozone

Alfalfa sprouts have been associated with numerous foodborne outbreaks. Previous studies investigated the effectiveness of aqueous ozone on bacterially contaminated seeds, yet little is known about the response of human norovirus (huNoV). This study assessed aqueous ozone for the disinfection of alfalfa seeds contaminated with huNoV and its surrogates. The inactivation of viruses without a food matrix was also investigated. Alfalfa seeds were inoculated with huNoV genogroup II, Tulane virus (TV), and murine norovirus (MNV); viruses alone or inoculated on seeds were treated in deionized water containing 6.25 ppm of aqueous ozone with agitation at 22°C for 0.5, 1, 5, 15, or 30 min. The data showed that aqueous ozone resulted in reductions of MNV and TV infectivity from 1.66 ± 1.11 to 5.60 ± 1.11 log PFU/g seeds; for all treatment times, significantly higher reductions were observed for MNV (P < 0.05). Viral genomes were relatively resistant, with a reduction of 1.50 ± 0.14 to 3.00 ± 0.14 log genomic copies/g seeds; the reduction of TV inoculated in water was similar to that of huNoV, whereas MNV had significantly greater reductions in genomic copies (P < 0.05). Similar trends were observed in ozone-treated viruses alone, with significantly higher levels of inactivation (P < 0.05), especially with reduced levels of infectivity for MNV and TV. The significant inactivation by aqueous ozone indicates that ozone may be a plausible substitute for chlorine as an alternative treatment for seeds. The behavior of TV was similar to that of huNoV, which makes it a promising surrogate for these types of scenarios.

Ultrasonication-enhanced seed germination and microbial safety of sprouts produced from selected crop species

Seed sprouts are susceptible to microbial contamination; therefore, use of an effective sanitization treatment on these products is of great importance. This study investigated the effects of ultrasonication, heating and chemical washing on sanitization of nine crop seeds and the microbial safety of sprouts produced from decontaminated seeds. The result showed that most of seed sanitization treatments increased germination (except dry heating), decreased microbial loads on treated seeds and subsequently produced sprouts, and increased sprouts yield. However, only ultrasonication seed treatment reduced both the total aerobic counts and total coliforms counts to < 3 log 10 CFU g -1 level on produced alfalfa, mung bean pea and radish sprouts. The sprouts produced from ultrasonication-treated alfalfa, mung bean pea and radish seeds also out yielded their respective non-treated sprounts by 88, 25, 73 and 56%. Therefore, ultrasonication can be used as a seed sanitization treatment for producing alfalfa, mung bean, pea and radish sprouts.