Fabrication of Robust and Stable N-Doped ZnO/Single-Walled Carbon Nanotubes: Characterization, Photocatalytic Application, Kinetics, Degradation Products, and Toxicity Analysis.

The production of effective visible-light (VL) photocatalysts for the elimination of noxious organic pollutants from wastewater has attracted considerable interest owing to increasing awareness worldwide. Despite the large number of photocatalysts reported, the selectivity and activity of photocatalysts still need to be developed. The goal of this research is to eliminate toxic methylene blue (MB) dye from wastewater through a cost-effective photocatalytic process using VL illumination. A novel N-doped ZnO/carbon nanotube (NZO/CNT) nanocomposite was successfully synthesized via a facile cocrystallization method. The structural, morphological, and optical properties of the synthesized nanocomposite were systematically investigated. The as-prepared NZO/CNT composite exhibited remarkable photocatalytic performance (96.58%) within 25 min of VL irradiation. The activity was 92, 52, and 27% greater than that of photolysis, ZnO, and NZO, respectively, under identical conditions. The enhanced photocatalytic efficiency of NZO/CNT was attributed to the N atom and CNT involvement: N contributes to narrowing the band gap of ZnO, and CNT captures the electrons and maintains the electron flow in the system. The reaction kinetics of MB degradation, catalyst reusability, and stability were also investigated. In addition, the photodegradation products and their toxicity effects in our environment were analyzed using the liquid chromatography-mass spectrometry and ecological structure activity relationships programs, respectively. The findings of the current study demonstrate that the NZO/CNT nanocomposite can be utilized to remove contaminants in an environmentally acceptable manner, thereby providing a new window for practical applications.

A case study of CO2 emissions from beef and pork production in South Korea.

The current study evaluated carbon dioxide (CO2) emissions from beef and pork production and distribution chains in the South Korean meat industry. Data from industrial example farms and slaughterhouses were assessed on the basis of both the guidelines from the United Kingdom's Publicly Available Specification (PAS) 2050:2011 and the Korea Environmental Industry & Technology Institute carbon footprint calculation. The main factors for our estimations were animal feeds, manure waste, transportation, energy and water, refrigerants, and package data. Our analyses show that 16.55 kg CO2 equivalent (eq) was emitted during the production of 1 kg of live cattle. When retail yields and packing processes were considered, the CO2-eq of 1 kg of packaged Hanwoo beef was 27.86 kg. As for pigs, emissions from 1 kg of live pigs and packaged pork meat were 2.62 and 12.75 kg CO2-eq, respectively. While we gathered data from only two farms and slaughterhouses and our findings can therefore not be extrapolated to all meats produced in the South Korean meat industry, they indicate that manure waste is the greatest factor affecting ultimate CO2 emissions of packaged meats.

Beef Toughness and the Amount of Greenhouse Gas Emissions as a Function of Localized Electrical Stimulation.

This study investigated the effect of localized electrical stimulation on Hanwoo beef quality. It focused on the chemical and physical properties of the Longissimus thoracis (LT) and Biceps femoris (BF) muscles, and it explored the implications of carbon dioxide (CO2) reduction achieved by accelerating tenderization via localized electrical stimulation. The results show that the application of localized electrical stimulation (45 V) had no significant impact on the TBARS (thiobarbituric acid reactive substances) of either the LT muscle or the BF muscle. Localized electrical stimulation and aging treatments had a significant effect on meat tenderness in the LT and BF muscles, but there was no interactive effect. In particular, the WBsf (Warnar-Bratzler shear force) at 2 days of aging of the electrically stimulated BF muscle was 5.35 kg, which was lower than that of the control group (5.58 kg) after 14 days of aging; however, the effect of WBsf reduction due to aging in the LT muscle was higher than the localized electrical stimulation effect. Estimating CO2 mitigation from a shorter feeding period for Hanwoo steers from 31 months to 26 months may reduce 1.04 kg of CO2-eq emissions associated with the production of a single kilogram of trimmed beef. In conclusion, localized electrical stimulation improved the tenderness of Hanwoo beef and reduced CO2 emissions.

Photocatalytic VOCs Degradation Efficiency of Polypropylene Membranes by Incorporation of TiO2 Nanoparticles.

A class of serious environmental contaminants related to air, namely volatile organic compounds (VOCs), has currently attracted global attention. The present study aims to remove harmful VOCs using as-prepared polypropylene membrane + TiO2 nanoparticles (PPM + TiO2 NPs) via the photocatalytic gas bag A method under UV light irradiation. Here, formaldehyde was used as the target VOC. The PPM + TiO2 NPs material was systematically characterized using various microscopic and spectroscopic techniques, including field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, photoluminescence spectroscopy, and contact angle measurements. These results confirm the successful preparation of PPM + TiO2 NPs, which can be applied to the degradation of VOCs. Photocatalytic degradation of formaldehyde gas reached 70% within 1 h of UV illumination. The energy bandgap and photoluminescence intensity reductions are responsible for the improved photocatalytic activity. These characteristics increase the charge transport while decreasing the recombination of electron-hole pairs.

Effects of Astragalus membranaceus, Adenophora triphylla, and Ulmus pumila Extracts on Quality Characteristics and Storage Stability of Sous-Vide Cooked Chicken Breasts.

This study aimed to investigate the influence of Astragalus membranaceus (AM), Adenophora triphylla (AT), and Ulmus pumila (UP) extracts on the quality traits, palatability, and storage stability of sous-vide (SV) cooked chicken breasts. Chicken breasts were marinated in AM, AT, or UP extracts for 1 h, and then consistently cooked at a constant temperature of 60°C for 2 h. SV cooked chicken breasts with the UP extract exhibited lower lightness and higher yellowness values on the surface region compared to those with the AM and AT extracts (p<0.05). The control and UP groups displayed a similar overall visual acceptability (p>0.05), although the UP group had lower color acceptability (p<0.01). The UP group also had higher flavor and lower off-flavor intensities compared to the control group (p<0.05), although similar scores were observed in tenderness attributes and juiciness among the groups (p>0.05). Owing to these results regarding overall sensory acceptability, samples from the UP group were more preferred by the trained panelists compared to samples from the control group (p<0.001). On 14 d of cold storage, all the groups with herbal medicinal extracts exhibited a lower concentration of thiobarbituric acid-reactive substances than the control group (p<0.05), and the AT and UP groups showed lower values compared to the AM group due to their higher flavonoid contents (p<0.001). Therefore, meat marination with herbal plant extracts before SV cooking can be effective for enhancing the overall quality of SV cooked chicken breast.

Muscle fiber and fresh meat characteristics of white-striping chicken breasts, and its effects on palatability of sous-vide cooked meat.

The aim of this study was to compare the histochemical and meat quality characteristics between the normal and white-striping (WS) pectoralis major muscles. Additionally, this study investigated the effects of oven cooking (OV) and sous-vide (SV) cooking methods on objective texture parameters and sensory quality characteristics of the normal and WS chicken breast meats. Results showed that the WS condition broilers had higher body and breast weights (P < 0.001), and a greater area of muscle fiber than the normal broilers (P < 0.001). The WS fresh fillets exhibited a lower preference of visual appearance compared to the normal fillets (P < 0.05), although no differences were detected in the characteristics of meat quality between the groups (P > 0.05). After cooking, there was greater cooking loss, Warner-Bratzler shear force, and texture parameter analysis-hardness values for breast fillets cooked by OV treatment at 180°C for reached core temperature to 71°C compared to the fillets cooked by SV treatment at 60°C for 2 h (P < 0.05), whereas the normal and WS groups were exhibited similar values within each cooking methods (P > 0.05). Regarding sensory quality characteristics, WS breast fillets cooked by SV (SV+WS) were rated as tenderer and juicier, and given a higher overall acceptability score compared to normal and WS fillets cooked by OV (P < 0.05). However, owing to a lesser developed flavor in SV+WS fillets, the panelists assigned a lower overall acceptability rating in these fillets compared to SV+Normal fillets (P < 0.05). Overall, the SV cooking can be an effective method for improving the sensory quality characteristics of WS and normal chicken breast.

Comparison of Quality Characteristics and Palatability between Sous-Vide Cooked Pork Loin Patties with Different Searing Treatments.

This study compared the quality, cooking, textural, and palatability characteristics between sous-vide (SV) cooked pork loin patties with different searing treatments (ST). Before SV cooking, STs were conducted on each side of the pork loin patties for 0 (control) to 120 s (ST120), and all patties were then cooked using an SV cooker at 75°C for 120 min. Noticeable differences were observed in quality properties between the groups. The seared SV loin patties exhibited lower lightness and higher browning index values compared to the unseared SV loin patties (p<0.001). Cooking loss gradually increased with increasing ST times, and the control group had a lower percentage compared to the ST60 group (19.5 vs. 25.7%, p<0.001). Changes in cooking properties were associated with the extent of ST, and the ST groups exhibited a higher hardness value compared to the control group (p<0.001). Regarding palatability, loin patties from the control group scored lower in appearance acceptability compared to patties from the ST groups (p<0.05) due to extent of browning on the surface. Moreover, the ST groups did exhibit a higher flavor intensity compared to the control group, but no differences were observed in tenderness and juiciness scores between the control and ST60 groups. Due to these results, the ST60 group exhibited a greater score in overall acceptability compared to the other groups except for the ST90 group. Therefore, an additional ST before SV cooking can achieve a more appealing appearance and palatability as well as to enhance the availability of pork loin.

Determination of toxic metal release from metallic kitchen utensils and their health risks.

The effect of simulants, repeated use, washing, and oiling on the release of toxic metals from metallic kitchen utensils was investigated. The release of As, Cd, Cr, Ni, and Pb from kitchen utensils composed of stainless steel, aluminum, copper alloy, and cast iron into food simulants was quantified using inductively coupled plasma-mass spectrometry. The results show that this release of toxic metals was highly dependent on pH. Generally, the release of toxic metals tended to decrease with repeated use, and the release of Cr and Ni from stainless steel samples was significantly higher in the first test, compared to the third test. The washing conditions affected the release of As and Cr, whose release levels were higher when washing only with water and with a steel wool pad, respectively. Furthermore, oiling cast iron cookware reduced the release of As, Cd, Cr, and Ni into acidic simulants by 66%, 83%, 71%, and 15%, respectively. The margin of exposure (MOE) was calculated for each toxic metal; the calculated MOE values indicated that it is improbable that the current level of exposure from metallic kitchen utensils would pose a health risk in Korea.

Effect of Searing Process on Quality Characteristics and Storage Stability of Sous-Vide Cooked Pork Patties.

This study investigated the effects of searing process before sous-vide (SV) treatment on quality traits, visual attributes, palatability, and storage stability of SV cooked pork patties. Patties were seared on each side by pan-frying for 0 (control), 30 (S30), 60 (S60), 90 (S90), or 120 (S120) s in a stainless-steel pan, and all patties were then vacuum-packed and cooked under thermally controlled conditions at 75 °C for 2 h. Marked differences were observed in quality properties between the control and searing groups, and the S120 group exhibited greater brown surface color and cooking loss compared to the other groups (p < 0.001) due to the additional heating process. Patties from the S60 group showed greater appearance and tenderness acceptability scores compared to patties from the S30 and S120 groups (p < 0.001). On another note, the effects of searing on storage stability were somewhat limited, as they were measured by 2-thiobarbituric acid reactive substance, volatile basic nitrogen, total aerobic bacterial count, and coliforms during 49 d of cold storage. Therefore, searing process before SV treatment can improve the visual attributes and palatability of cooked pork patties, and the optimum searing condition was for 60 s, without impairing the storage stability.

Potential for short-term migration of mineral oil hydrocarbons from coated and uncoated food contact paper and board into a fatty food simulant.

Mineral oil hydrocarbons (MOH) are widely used in the food industry for applications such as printing inks, additives, adhesives, and processing aids for food additives. Recently, the migration of MOH from food contact paper and board into foods has raised public health concerns. In this study, a total of 110 food contact paper and board samples, including baking and cooking paper (23), baking cups (28), food packaging bags (22), lunch boxes (8), party plates (26), and straws (3) were evaluated to quantify the content and short-term migration levels of MOH. The MOH were separated into mineral oil saturated hydrocarbons (MOSH)/polyolefin oligomeric saturated hydrocarbons (POSH) and mineral oil aromatic hydrocarbons (MOAH) via a validated on-line liquid chromatography-gas chromatography-flame ionisation detection (LC-GC-FID) technique. The coating materials of the sample products comprised polyethylene, polypropylene, polyethylene terephthalate, and silicone. The effects of the coating materials on the content and migration of MOH/POSH were evaluated. Quantitative analysis of the MOH in the samples showed that the MOSH/POSH and MOAH content varied widely, ranging from 16 to 5626 mg kg-1 for MOH, regardless of the coating materials. Short-term migration of MOSH/POSH was observed only in samples with polyolefinic coatings, such as polyethylene and polypropylene, in experiments conducted at 25 °C for 10 min, although the extent of MOAH migration for all samples was at the trace level. The migration of MOSH/POSH was detected within the range of 0.93 to 62.3 µg L-1 in 22 samples, and the migration of MOAH was detected within the range of 0.80 to 2.6 µg L-1 in only 4 samples. These results demonstrate that although the short-term migration potential of MOH is generally negligible, the migration of MOSH/POSH into wet fatty foods can be accelerated by polyolefinic coatings, even within a very short time.

The quality characteristics, antioxidant activity, and sensory evaluation of reduced-fat yogurt and nonfat yogurt supplemented with basil seed gum as a fat substitute.

This study investigated the use of basil seed gum (BSG) as a fat substitute on the physicochemical properties and antioxidant activities of yogurt. A 0.5 and 1% BSG solution was supplemented to reduced-fat and nonfat yogurts, and their physicochemical properties, quality properties, antioxidant activity, and sensory evaluation were compared with each control group. We prepared 3 yogurts as controls and 4 yogurt samples containing BSG as follows: FFY (yogurt made from full-fat milk: a control group), LFY (yogurt made from reduced-fat milk: a control group), SY (yogurt made from nonfat milk: a control group), LFY 0.5% (0.5% BSG added to reduced-fat yogurt), LFY 1.0% (1.0% BSG added to reduced-fat yogurt), SY 0.5% (0.5% BSG added to nonfat yogurt), and SY 1.0% (1.0% BSG added to nonfat yogurt). The pH of LFY 0.5% and LFY 1.0% was decreased compared with LFY control, whereas pH of SY 0.5% and SY 1.0% had no significant difference. The titratable acidity showed no significant increase. The viscosity was the highest in FFY among the control groups and increased with the concentration of BSG in the SY group. The L-value (brightness) and b-value (yellowness) were the highest in FFY at 85.05 among the control groups. The L-value and b-value of LFY 0.5% and SY 0.5% showed higher values than LFY 1% and SY 1%. The a-value (redness) was the highest in SY 0.5% at -2.36, and ΔE (total color difference) was the highest in SY 1% at 7.33. The moisture content of SY was the highest among the control groups and addition of 1% BSG to SY was highest among the BSG-added group. Total contents of phenol and flavonoid slightly increased as the concentration of BSG increased (increase in the contents of phenol and flavonoid). The results of ferric reducing antioxidant power were similar to the findings of phenol and flavonoid content (an increase as the concentration of BSG increased). The overall acceptability of sensory characteristics was improved in all groups of samples when BSG 1% concentration increased. Application of BSG for the production of nonfat yogurt can enhance physicochemical properties, antioxidant activity, and sensory characteristics of reduced-fat and nonfat yogurt. Addition of BSG to reduced-fat and nonfat yogurt can improve their physical and antioxidant properties to the level of FFY.

Effects of Different Marination Conditions on Quality, Microbiological Properties, and Sensory Characteristics of Pork Ham Cooked by the Sous-vide Method.

The aim of this study was to evaluate the effects of marinade under different conditions (temperature and vacuum) on pork ham cooked by the sous-vide method (61°C and 98.81% vacuum for 45 min). Control group was non-marinade pork ham. The samples were marinated under 1 of 4 conditions: 4°C, 98.81% vacuum (treatment group T1); 4°C, atmospheric pressure (T2); 20°C, 98.81% vacuum (T3); and 20°C, atmospheric pressure (T4). The pH value was higher in the control (6.02) than in the treatment groups (4.30-4.42, p<0.001). Shear force was the lowest in the control: 18.14 N. Lightness and redness values were higher in the control (p<0.001). The chroma value significantly decreased from 12.74 to 7.55 with marinade (p<0.001). Total viable and coliform counts of raw meat were 84.6 and 3.67 Log CFU/g, respectively. After the marinade, the total viable count decreased to 3.00-14.67 Log CFU/g (p<0.001). Coliforms were not detected. After sous-vide cooking, no viable microorganisms were detected in any group. Treatment groups generally showed high scores on consumer preference. The marinade and sous-vide cooking had a positive effect on sensory characteristics. They provided safe conditions for sanitary evaluation. As a result, it appears that marinade at refrigeration temperature is better than that at room temperature.

Effects of sous-vide method at different temperatures, times and vacuum degrees on the quality, structural, and microbiological properties of pork ham.

This study evaluated the influence of different factors on pork hams cooked by sous-vide method. The quality and structural and microbiological properties of the treated samples were compared with those of controls. Samples were subjected to treatment at different combinations of temperature (61 °C or 71 °C), time (45 or 90 min), and vacuum degree (98.81% or 96.58%). The control sample was air packaged and boiled for 45 min in boiling water. Temperature and vacuum degree affected quality properties, while the effect of time was limited. Samples cooked at 61 °C showed higher moisture content, redness, and pink color of the meat juice, whereas samples cooked at 71 °C showed higher cooking loss rate, lightness, and volatile basic nitrogen values. Texture analysis indicated tenderer meat for the treatment group than the control. No microbial growth was detected in any treatment groups. Meat cooked at 61 °C and 98.81% vacuum showed more spacious arrangement of meat fiber.

Quantitative analysis of menthol and identification of other flavoring ingredients in capsule cigarettes marketed in Korea.

Currently, capsule cigarettes have been introduced by tobacco industries and their sales have increased exponentially. However, the capsule flavoring ingredients and their safety are still unknown. Although the contents of menthol and other ingredients directly added to cigarettes have been determined extensively, no analogous study exists for menthol-containing cigarette capsules. Basic physical properties of capsules in all 31 different capsule cigarettes commercially available in Korea were investigated, and their menthol contents were determined in this study. Other ingredients in these capsules were also qualitatively analyzed; methyl octanoate, menthone and isopulegol as well as menthol were detected in all the capsules. There is considerable variability in basic physical properties and menthol contents of cigarette capsules depending on their brand styles. The menthol contents of capsules and whole cigarettes are similar or higher than those previously reported for conventional menthol cigarettes. This is the first report on the physical properties of capsules and the fact that a wide range of menthol contents in capsule cigarettes, regardless of flavor types, allows smokers to select menthol content to their liking.

A Fungus-Inducible Pepper Carboxylesterase Exhibits Antifungal Activity by Decomposing the Outer Layer of Fungal Cell Walls.

Colletotrichum species are major fungal pathogens that cause devastating anthracnose diseases in many economically important crops. In this study, we observed the hydrolyzing activity of a fungus-inducible pepper carboxylesterase (PepEST) on cell walls of C. gloeosporioides, causing growth retardation of the fungus by blocking appressorium formation. To determine the cellular basis for the growth inhibition, we observed the localization of PepEST on the fungus and found the attachment of the protein on surfaces of conidia and germination tubes. Moreover, we examined the decomposition of cell-wall materials from the fungal surface after reaction with PepEST, which led to the identification of 1,2-dithiane-4,5-diol (DTD) by gas chromatography mass spectrometry analysis. Exogenous DTD treatment did not elicit expression of defense-related genes in the host plant but did trigger the necrosis of C. gloeosporioides. Furthermore, the DTD compound displayed protective effects on pepper fruits and plants against C. gloeosporioides and C. coccodes, respectively. In addition, DTD was also effective in preventing other diseases, such as rice blast, tomato late blight, and wheat leaf rust. Therefore, our results provide evidence that PepEST is involved in hydrolysis of the outmost layer of the fungal cell walls and that DTD has antifungal activity, suggesting an alternative strategy to control agronomically important phytopathogens.

7,10-Epoxyoctadeca-7,9-dienoic Acid: A Small Molecule Adjuvant That Potentiates ß-Lactam Antibiotics Against Multidrug-Resistant Staphylococcus aureus.

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) infections with multi-drug resistance needs effective and alternative control strategies. In this study we investigated the adjuvant effect of a novel furan fatty acid, 7,10-epoxyoctadeca-7,9-dienoic acid (7,10-EODA) against multidrug-resistant S. aureus (MDRSA) strain 01ST001 by disc diffusion, checker board and time kill assays. Further the membrane targeting action of 7,10-EODA was investigated by spectroscopic and confocal microscopic studies. 7,10-EODA exerted synergistic activity along with ß-lactam antibiotics against all clinical MRSA strains, with a mean fractional inhibitory concentration index below 0.5. In time-kill kinetic study, combination of 7,10-EODA with oxacillin, ampicillin, and penicillin resulted in 3.8-4.2 log10 reduction in the viable counts of MDRSA 01ST001. Further, 7,10-EODA dose dependently altered the membrane integrity (p < 0.001) and increased the binding of fluorescent analog of penicillin, Bocillin-FL to the MDRSA cells. The membrane action of 7,10-EODA further facilitated the uptake of several other antibiotics in MDRSA. The results of the present study suggested that 7,10-EODA could be a novel antibiotic adjuvant, especially useful in repurposing ß-lactam antibiotics against multidrug-resistant MRSA.

Overexpression of Arabidopsis thaliana brassinosteroid-related acyltransferase 1 gene induces brassinosteroid-deficient phenotypes in creeping bentgrass.

Brassinosteroids (BRs) are naturally occurring steroidal hormones that play diverse roles in various processes during plant growth and development. Thus, genetic manipulation of endogenous BR levels might offer a way of improving the agronomic traits of crops, including plant architecture and stress tolerance. In this study, we produced transgenic creeping bentgrass (Agrostis stolonifera L.) overexpressing a BR-inactivating enzyme, Arabidopsis thaliana BR-related acyltransferase 1 (AtBAT1), which is known to catalyze the conversion of BR intermediates to inactive acylated conjugates. After putative transgenic plants were selected using herbicide resistance assay, genomic integration of the AtBAT1 gene was confirmed by genomic PCR and Southern blot analysis, and transgene expression was validated by northern blot analysis. The transgenic creeping bentgrass plants exhibited BR-deficient phenotypes, including reduced plant height with shortened internodes (i.e., semi-dwarf), reduced leaf growth rates with short, wide, and thick architecture, high chlorophyll contents, decreased numbers of vascular bundles, and large lamina joint bending angles (i.e., erect leaves). Subsequent analyses showed that the transgenic plants had significantly reduced amounts of endogenous BR intermediates, including typhasterol, 6-deoxocastasterone, and castasterone. Moreover, the AtBAT1 transgenic plants displayed drought tolerance as well as delayed senescence. Therefore, the results of the present study demonstrate that overexpression of an Arabidopsis BR-inactivating enzyme can reduce the endogenous levels of BRs in creeping bentgrass resulting in BR-deficient phenotypes, indicating that the AtBAT1 gene from a dicot plant is also functional in the monocot crop.

High Hydrostatic Pressure Extract of Ginger Exerts Antistress Effects in Immobilization-Stressed Rats.

Stress contributes to physiological changes such as weight loss and hormonal imbalances. The aim of the present study was to investigate antistress effects of high hydrostatic pressure extract of ginger (HPG) in immobilization-stressed rats. Male Sprague-Dawley rats (n = 24) were divided into three groups as follows: control (C), immobilization stress (2 h daily, for 2 weeks) (S), and immobilization stress (2 h daily, for 2 weeks) plus oral administration of HPG (150 mg/kg body weight/day) (S+G). Immobilization stress reduced the body weight gain and thymus weight by 50.2% and 31.3%, respectively, compared to the control group. The levels of serum aspartate transaminase, alanine transaminase, and corticosterone were significantly higher in the stress group, compared to the control group. Moreover, immobilization stress elevated the mRNA levels of tyrosine hydroxylase (Th), dopamine beta-hydroxylase (Dbh), and cytochrome P450 side-chain cleavage (P450scc), which are related to catecholamine and corticosterone synthesis in the adrenal gland. HPG administration also increased the body weight gain and thymus weight by 12.7% and 16.6%, respectively, compared to the stress group. Furthermore, the mRNA levels of Th, Dbh, phenylethanolamine-N-methyltransferase, and P450scc were elevated by the HPG treatment when compared to the stress group. These results suggest that HPG would have antistress effects partially via the reversal of stress-induced physiological changes and suppression of mRNA expression of genes related to corticosterone and catecholamine synthetic enzymes.

Inactivation of Clostridium difficile spore outgrowth by synergistic effects of nisin and lysozyme.

Inactivating Clostridium difficile spores is difficult, as they are resistant to heat, chemicals, and antimicrobials. However, this note describes inactivation of C. difficile spore outgrowth by incubation in a solution containing a germinant (1% (m/v) sodium taurocholate), co-germinants (1% (m/v) tryptose and 1% (m/v) NaCl), and natural antimicrobials (20 nmol·L-1 nisin and 0.2 mmol·L-1 lysozyme). Clostridium difficile spores were resistant to nisin and lysozyme but became susceptible during germination and outgrowth triggered and promoted by sodium taurocholate, tryptose, and NaCl. The degree of inactivation of germinated and outgrowing C. difficile spores by both nisin and lysozyme was greater than the sum of that by nisin and lysozyme individually, suggesting synergistic inactivation of C. difficile spores. The germinant, co-germinants, and natural antimicrobials used in this study are safe for human contact and consumption. Therefore, these findings will facilitate the development of a safe and effective method to inactivate C. difficile spore.