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1.
J Microbiol Biotechnol ; 33(4): 419-429, 2023 Apr 28.
Article in English | MEDLINE | ID: mdl-36788459

ABSTRACT

Ultraviolet C (UV-C, 200-280 nm) light has germicidal properties that inactivate a wide range of pathogenic and spoilage microorganisms. UV-C has been extensively studied as an alternative to thermal decontamination of fruit juices. Recent studies suggest that the efficacy of UV-C irradiation in reducing microorganisms in fruit juices is greatly dependent on the characteristics of the target microorganisms, juice matrices, and parameters of the UV-C treatment procedure, such as equipment and processing. Based on evidence from recent studies, this review describes how the characteristics of target microorganisms (e.g., type of microorganism/strain, acid adaptation, physiological states, single/composite inoculum, spore, etc.) and fruit juice matrices (e.g., UV absorbance, UV transmittance, turbidity, soluble solid content, pH, color, etc.) affect the efficacy of UV-C. We also discuss the influences on UV-C treatment efficacy of parameters, including UV-C light source, reactor conditions (e.g., continuous/batch, size, thickness, volume, diameter, outer case, configuration/arrangement), pumping/flow system conditions (e.g., sample flow rate and pattern, sample residence time, number of cycles), homogenization conditions (e.g., continuous flow/recirculation, stirring, mixing), and cleaning capability of the reactor. The collective facts indicate the immense potential of UV-C irradiation in the fruit juice industry. Existing drawbacks need to be addressed in future studies before the technique is applicable at the industrial scale.


Subject(s)
Decontamination , Fruit and Vegetable Juices , Chemical Phenomena , Acids/analysis , Ultraviolet Rays , Fruit/chemistry
2.
Food Res Int ; 162(Pt B): 112159, 2022 12.
Article in English | MEDLINE | ID: mdl-36461367

ABSTRACT

In this study, malic acid treatment under different conditions, including molarity level (2-4 M), temperatures (90-130 °C), and time (2-12 h), was evaluated to prepare a modified wheat starch that is rich in resistant starch (RS). The physicochemical characteristics of the modified starch were also investigated. The application of 4 M malic acid and a heat treatment at 130 °C for 7 h produced a malic acid-treated (MT) wheat starch composed of 99.5 % RS. Fourier-transform infrared spectroscopy of MT wheat starch displayed a distinct carbonyl peak at around 1,740 cm-1, is formed due to the stretching vibration of the CO bond of the ester group. The crystalline and double-helix structures of the MT wheat starch were extensively destroyed, resulting in its enhanced degree of substitution, number of cross-linking bonds, and thermostable RS content (99 %) as well as its reduced viscosity. Furthermore, its consumption in vivo reduced the blood glucose level and response. The starch modification method reported herein could be applied when preparing RS-rich wheat starch for use in the production of heat-processed foods with high fiber contents and low calories.


Subject(s)
Resistant Starch , Triticum , Starch , Malates
3.
Food Sci Biotechnol ; 31(8): 935-956, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35873372

ABSTRACT

Phenolic compounds in common buckwheat sprouts (CBSs) have gained research interest because of their multiple health benefits. Phenolic acids, flavanones, flavonols, flavan-3-ols, and anthocyanins are important bioactive components of CBS that exhibit biological activities, including anti-inflammatory, antioxidant, anti-proliferative, and immunomodulatory effects. The isolation and quantitative and qualitative analyses of these phenolic compounds require effective and appropriate extraction and analytical methods. The most recent analytical method developed for determining the phenolic profile is HPLC coupled with a UV-visible detector and/or MS. This review highlights the extraction, purification, analysis, and bioactive properties of phenolic compounds from CBS described in the literature.

4.
Food Chem ; 366: 130526, 2022 Jan 01.
Article in English | MEDLINE | ID: mdl-34274705

ABSTRACT

An in-house method, employing magnetic stirring-assisted aqueous extraction combined with gas chromatography-flame ionization detector, for determination of ethanol in different foods and beverages was validated according to the ISO/IEC 17025 standard. Validation parameters, including selectivity, method limits of detection (approx. 0.006 mg/g) and quantification (approx. 0.02 mg/g), linearity (R2 of >0.999), trueness (relative biases of <3%), accuracy (recoveries of 96-105%), and precision (relative standard deviations of <5%), were satisfactory. The proposed method was as accurate and precise as and more sensitive than the AOAC method 2016.12, with estimated relative expanded uncertainties of around 8% for all samples. The validated method was successfully applied for determination of ethanol in 108 commercially processed foods and beverages, and it could be used for halal verification. Accordingly, this study provided a reliable method for routine quantitative analysis of ethanol in processed foods and beverages to ensure their halal integrity prior to halal certification.


Subject(s)
Beverages , Ethanol , Beverages/analysis , Chromatography, Gas , Magnetic Phenomena , Water
5.
Acta Med Indones ; 53(1): 42-51, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33818406

ABSTRACT

BACKGROUND: type 2 diabetes mellitus (T2DM) and gastroesophageal reflux disease (GERD) are commonly seen in the geriatric population. This study aimed to investigate the prevalence, risk factors, and alarm-symptoms incidence of GERD among elderly patients with T2DM in a rural area of Central Sulawesi. METHODS: this cross-sectional study was conducted from July-September 2019 in Public Health Center of Beteleme, Central Sulawesi. Patients aged ≥60 years old, newly or previously diagnosed with T2DM according to the 2019 American Diabetes Association (ADA) criteria or to the 2015 Indonesian Society of Endocrinology (PERKENI) criteria, were consecutively recruited. We excluded patients being on proton-pump inhibitor or H2-receptor antagonist therapy or having a history of gastric or esophageal surgery. GERD was diagnosed in patients with the score of ≥8 based on the Indonesian version of GERD questionnaire (GERD-Q). RESULTS: among 60 elders with T2DM, 28.3% (95% confidence interval [CI], 16.9-39.7) had GERD. Statistical analysis showed that GERD was significantly associated with consumption frequency of tea (p=0.019) and coffee (p=0.015). No significant relationship was found between gender (p=0.562), obesity (p=0.803), achievement of blood glucose-level control (p=0.478), duration of T2DM (p=0.304), and type of antihyperglycemic drugs (p=0.202) with GERD. Unintentional weight loss was the leading alarm symptom (47.1%; 95%CI, 23.4%-70.8%) found across the GERD group. CONCLUSION: GERD was prevalent among elderly patients with diabetes. Frequent consumption of either tea or coffee was associated with GERD. Alarm symptoms need further evaluation to screen for complications.


Subject(s)
Diabetes Mellitus, Type 2/complications , Gastroesophageal Reflux/epidemiology , Aged , Aged, 80 and over , Cross-Sectional Studies , Female , Humans , Incidence , Indonesia/epidemiology , Male , Middle Aged , Obesity/complications , Prevalence , Risk Factors , Surveys and Questionnaires
6.
Food Chem ; 298: 125050, 2019 Nov 15.
Article in English | MEDLINE | ID: mdl-31260955

ABSTRACT

An analytical method involving QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation, followed by LC-MS/MS and GC-MS/MS was developed and validated for the determination of 60 pesticides in eggs. Recoveries of 70-120% were achieved for selected pesticides and relative standard deviations <20% were obtained for most analytes at three concentrations. The limit of quantification was <10 µg kg-1 for 83% of the total pesticides. This method was used to analyze 58 egg samples and the residues of seven pesticides (disulfoton, fipronil sulfone, cyromazine, o,p-DDT, p,p-DDD, p,p-DDT, and permethrin) were quantified in 16 egg samples at levels of 5-10 µg kg-1, which was below the corresponding the maximum residue levels, as established by Korean Ministry of Food and Drug Safety. We demonstrated that LC-MS/MS and GC-MS/MS in combination with QuEChERS can be used to routinely monitor multiple pesticide residues in egg samples.


Subject(s)
Gas Chromatography-Mass Spectrometry/methods , Pesticide Residues/analysis , Tandem Mass Spectrometry/methods , Animals , Chickens , Chromatography, High Pressure Liquid , Disulfoton/analysis , Eggs/analysis , Female , Limit of Detection , Pyrazoles/analysis , Reproducibility of Results
7.
Food Chem ; 293: 438-445, 2019 Sep 30.
Article in English | MEDLINE | ID: mdl-31151632

ABSTRACT

In this study, deep eutectic solvents (DESs) coupled with ultrasound-assisted extraction (UAE) were evaluated and optimized for the extraction of major flavonoids from common buckwheat sprouts. Initially, 18 different choline chloride (CC)-based DESs were evaluated as potential extraction solvents, and 80% CCTG (CC-based DES composed of triethylene glycol and 20 vol% water) extracted significantly higher (p < 0.05) amounts of flavonoids than other DESs studied. The extraction efficiency of 80% CCTG was even higher (p < 0.05) than that of methanol for the extraction of vitexin and quercetin-3-O-robinobioside. Procedure using 80% CCTG and UAE were optimized; an extraction temperature of 56 °C and extraction time of 40 min were considered optimal. The optimized extraction procedure was reliable and efficient for the extraction of major flavonoids from common buckwheat sprouts. In addition, flavonoids could be efficiently recovered from DES extracts with high recovery yields (>97%) by using a C18 solid-phase extraction.


Subject(s)
Fagopyrum/chemistry , Flavonoids/chemistry , Plant Extracts/chemistry , Solvents/chemistry , Chromatography, High Pressure Liquid , Fagopyrum/metabolism , Flavonoids/isolation & purification , Solid Phase Extraction , Sonication , Temperature
8.
Food Microbiol ; 77: 166-172, 2019 Feb.
Article in English | MEDLINE | ID: mdl-30297047

ABSTRACT

Microbial spoilage is a complex event to which different bacterial populations and metabolites can contribute depending on the storage conditions. This study explored the evolution of spoilage and related volatile organic compounds (VOCs) in chilled beef under air and vacuum packaging (VP). The results suggested that different storage conditions affected changes in bacterial communities and metabolites in beef and consequently affected the odor properties of the stored beef, thereby leading to spoilage. Bacterial species belonging to Pseudomonadaceae (Pseudomonas spp.) and lactic acid bacteria (Lactobacillus sp.) dominated the bacterial communities in beef stored under air and VP, respectively, with several VOCs associated with off-odors of the stored beef and most likely produced by both bacteria. Our results suggested several microbial VOCs that could be used as potential spoilage indicators, including acetic acid, butanoic acid, and 2-butanone in VP-stored beef and 3-methylbutan-1-ol, ethyl acetate, acetoin, 2-butanone, and diacetyl in air-stored beef. These findings might provide valuable information regarding the quality monitoring of beef during storage.


Subject(s)
Bacteria/classification , Bacteria/metabolism , Cold Temperature , Food Microbiology , Food Packaging/methods , Microbiota , Red Meat/microbiology , Air , Animals , Bacteria/growth & development , Biodiversity , Cattle , Colony Count, Microbial , Food Storage , Lactobacillus/growth & development , Lactobacillus/metabolism , Odorants/analysis , Pseudomonadaceae/growth & development , Pseudomonadaceae/metabolism , Vacuum , Volatile Organic Compounds/analysis , Volatile Organic Compounds/metabolism
9.
J Microbiol Biotechnol ; 27(6): 1090-1097, 2017 Jun 28.
Article in English | MEDLINE | ID: mdl-28376611

ABSTRACT

Rhus verniciflua Stokes (RVS), an herbal medicine found in East Asia, was extracted and further fractionated to investigate its antioxidant capacity and neuroprotective effects. The RVS ethyl acetate (EtOAc) fraction had the highest level of total phenolics and antioxidant capacity among all solvent fractions tested. Pretreatment of PC-12 cells with the EtOAc fraction effectively attenuated H2O2-induced oxidative damage. Furthermore, the EtOAc fraction significantly attenuated caspase-3 activity, resulting in inhibition of H2O2-induced apoptosis. We identified and quantified fustin, sulfuretin, and butein in the EtOAc fraction using accurate mass quadrupole time-of-flight mass spectrometry and reversed-phase high-performance liquid chromatography. The intracellular antioxidant capacity and superoxide dismutase (SOD) activity were significantly increased in PC-12 cells treated with the EtOAc fraction and with individual flavonoids. When cells were pretreated with the EtOAc fraction or individual flavonoids and then co-incubated with diethyldithiocarbamic acid (an inhibitor of SOD activity), cell viability against H2O2-induced oxidative stress was attenuated. These results suggest that the RVS EtOAc fraction and its flavonoid constituents protect PC-12 cells against H2O2-induced neurotoxicity through their antioxidant properties.


Subject(s)
Cell Survival/drug effects , Flavonoids/pharmacology , Hydrogen Peroxide/pharmacology , Oxidative Stress/drug effects , Plant Extracts/pharmacology , Rhus/chemistry , Animals , Antioxidants/pharmacology , Apoptosis/drug effects , Benzofurans/pharmacology , Caspase 3/metabolism , Chalcones/pharmacology , Ditiocarb/pharmacology , Flavonoids/chemistry , Flavonoids/isolation & purification , Neurons/drug effects , PC12 Cells , Phenols/pharmacology , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Rats , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Superoxide Dismutase/metabolism
10.
J Food Sci ; 81(8): M2021-30, 2016 Aug.
Article in English | MEDLINE | ID: mdl-27387251

ABSTRACT

The growth of epiphytic bacteria (aerobic mesophilic bacteria or Pseudomonas spp.) on kale was modeled isothermally and validated under dynamic storage temperatures. Each bacterial count on kale stored at isothermal conditions (4 to 25 °C) was recorded. The results show that maximum growth rate (µmax ) of both epiphytic bacteria increased and lag time (λ) decreased with increasing temperature (P < 0.05). The maximum population density (Nmax ) of Pseudomonas spp. was significantly greater than that of aerobic mesophilic bacteria, particularly in treated samples and/or at 4 and 10 °C (P < 0.05). The relationship between µmax of both epiphytic bacteria and temperature was linear (R(2) > 0.97), whereas lower R(2) > 0.86 and R(2) > 0.87 was observed for the λ and Nmax , respectively. The overall predictions of both epiphytic bacterial growths under nonisothermal conditions with temperature abuse of 15 °C agreed with the observed data, whereas those with temperature abuse of 25 °C were greatly overestimated. The appropriate parameter q0 (physiological state of cells), therefore, was adjusted by a trial and error to fit the model. This study demonstrates that the developed model was able to predict accurately epiphytic bacterial growth on kale stored under nonisothermal conditions particularly those with low temperature abuse of 15 °C.


Subject(s)
Bacteria/growth & development , Brassica/microbiology , Food Handling/methods , Food Microbiology , Models, Biological , Temperature , Colony Count, Microbial , Electrolysis , Food Storage/methods , Humans , Hydrogen-Ion Concentration , Pseudomonas/growth & development , Ultrasonic Waves , Water
11.
J Food Prot ; 79(1): 132-7, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26735039

ABSTRACT

Recent Staphylococcus aureus outbreaks linked to meat and poultry products underscore the importance of understanding the growth kinetics of S. aureus in these products at different temperatures. Raw pork, ham, and sausage (each 10 ± 0.3 g) were inoculated with a three-strain cocktail of S. aureus, resulting in an initial level of ca. 3 log CFU/g. Samples were stored isothermally at 10, 15, 20, 25, 30, 35, and 40°C, and S. aureus was enumerated at appropriate time intervals. The square root model was developed using experimental data collected from S. aureus grown on all samples (where data from raw pork, ham, and sausage were combined) so as to describe the growth rate of S. aureus as a function of temperature. The model was then compared with models for S. aureus growth on each individual sample in the experiments (raw pork, ham, or sausage) and the S. aureus ComBase models, as well as models for the growth of different types of pathogens (S. aureus, Escherichia coli O157:H7, Clostridium perfringens, Salmonella serovars, and Salmonella Typhimurium) on various types of meat and poultry products. The results show that the S. aureus model developed here based on the pooled data from all three pork products seems suitable for the prediction of S. aureus growth on different pork products under isothermal conditions from 10 to 25°C, as well as for S. aureus growth on different meat and poultry products at higher temperatures between 20 and 35°C. Regardless of some high deviations observed at temperatures between 25 and 40°C, the developed model still seems suitable to predict the growth of other pathogens on different types of meat and poultry products over the temperature ranges used here, especially for E. coli O157:H7 and Salmonella Typhimurium. The developed model, therefore, may be useful for estimating the effects of storage temperature on the behavior of pathogens in different meat and poultry products and for microbial risk assessments evaluating meat safety.


Subject(s)
Meat Products/microbiology , Red Meat/microbiology , Staphylococcus aureus/growth & development , Animals , Cattle , Colony Count, Microbial , Escherichia coli O157/chemistry , Escherichia coli O157/growth & development , Food Handling/methods , Kinetics , Meat Products/analysis , Models, Biological , Red Meat/analysis , Risk Assessment , Salmonella typhimurium/chemistry , Salmonella typhimurium/growth & development , Staphylococcus aureus/chemistry , Swine
12.
Food Microbiol ; 51: 154-62, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26187840

ABSTRACT

This study evaluated the efficacy of thermosonication combined with slightly acidic electrolyzed water (SAcEW) on the shelf life extension of fresh-cut kale during storage at 4 and 7 °C. Each kale (10 ± 0.2 g) was inoculated to contain approximately 6 log CFU/g of Listeria monocytogenes. Each inoculated or uninoculated samples was dip treated at 40 °C for 3 min with deionized water, thermosonication (400 W/L), SAcEW (5 mg/L), sodium chlorite (SC; 100 mg/L), sodium hypochlorite (SH; 100 mg/L), and thermosonication combined with SAcEW, SC, and SH (TS + SAcEW, TS + SC, and TS + SH, respectively). Growths of L. monocytogenes and spoilage microorganisms and changes in sensory (overall visual quality, browning, and off-odour) were evaluated. The results show that lag time and specific growth rate of each microorganism were not significantly (P > 0.05) affected by treatment and storage temperature. Exceeding the unacceptable counts of spoilage microorganisms did not always result in adverse effects on sensory attributes. This study suggests that TS + SAcEW was the most effective method to prolong the shelf life of kale with an extension of around 4 and 6 days at 4 and 7 °C, respectively, and seems to be a promising method for the shelf life extension of fresh produce.


Subject(s)
Bacteria/growth & development , Brassica/microbiology , Food Preservation/methods , Food Quality , Refrigeration , Bacteria/drug effects , Chlorides/pharmacology , Colony Count, Microbial , Electrolysis , Escherichia coli O157/drug effects , Escherichia coli O157/growth & development , Food Microbiology , Humans , Hydrogen-Ion Concentration , Listeria monocytogenes/drug effects , Listeria monocytogenes/growth & development , Sodium Hypochlorite/pharmacology , Sonication , Temperature , Water
13.
J Food Sci ; 80(6): M1277-84, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25944413

ABSTRACT

This study evaluated the efficacy of individual treatments (thermosonication [TS+DW] and slightly acidic electrolyzed water [SAcEW]) and their combination on reducing Escherichia coli O157:H7, Listeria monocytogenes, and spoilage microorganisms (total bacterial counts [TBC], Enterobacteriaceae, Pseudomonas spp., and yeast and mold counts [YMC]) on fresh-cut kale. For comparison, the antimicrobial efficacies of sodium chlorite (SC; 100 mg/L) and sodium hypochlorite (SH; 100 mg/L) were also evaluated. Each 10 g sample of kale leaves was inoculated to contain approximately 6 log CFU/g of E. coli O157:H7 or L. monocytogenes. Each inoculated or uninoculated samples was then dip treated with deionized water (DW; control), TS+DW, and SAcEW at various treatment conditions (temperature, physicochemical properties, and time) to assess the efficacy of each individual treatment. The efficacy of TS+DW or SAcEW was enhanced at 40 °C for 3 min, with an acoustic energy density of 400 W/L for TS+DW and available chlorine concentration of 5 mg/L for SAcEW. At 40 °C for 3 min, combined treatment of thermosonication 400 W/L and SAcEW 5 mg/L (TS+SAcEW) was more effective in reducing microorganisms compared to the individual treatments (SAcEW, SC, SH, and TS+DW) and combined treatments (TS+SC and TS+SH), which significantly (P < 0.05) reduced E. coli O157:H7, L. monocytogenes, TBC, Enterobacteriaceae, Pseudomonas spp., and YMC by 3.32, 3.11, 3.97, 3.66, 3.62, and >3.24 log CFU/g, respectively. The results suggest that the combined treatment of TS+SAcEW has the potential as a decontamination process in fresh-cut industry.


Subject(s)
Anti-Infective Agents/pharmacology , Brassica/microbiology , Food Handling/methods , Food Microbiology , Hot Temperature , Ultrasonic Waves , Water/pharmacology , Chlorine/pharmacology , Colony Count, Microbial , Electrolysis , Escherichia coli O157/drug effects , Escherichia coli O157/growth & development , Food Preservation/methods , Humans , Hydrogen-Ion Concentration , Listeria monocytogenes/drug effects , Listeria monocytogenes/growth & development , Sodium Hypochlorite/pharmacology , Sonication
14.
Microorganisms ; 3(1): 34-46, 2015 Feb 12.
Article in English | MEDLINE | ID: mdl-27682077

ABSTRACT

Sanitizing effectiveness of slightly acidic electrolyzed water (SAEW) and fumaric acid (FA) at different dipping temperatures (25-60 °C), times (1-5 min), and concentrations (5-30 ppm for SAEW and 0.125%-0.5% for FA) on pure cultures of two Gram positive pathogens Staphylococcus aureus (SA) and Listeria monocytogenes (LM) and two Gram negative pathogens Escherichia coli O157:H7 (EC) and Salmonella Typhimurium (ST) was evaluated. FA (0.25%) showed the strongest sanitizing effect, demonstrating complete inactivation of EC, ST, and LM, while SA was reduced by 3.95-5.76 log CFU/mL at 25-60 °C, respectively, after 1 min of treatment. For SAEW, the complete inactivation was obtained when available chlorine concentration was increased to 20 ppm at 40 °C for 3 and 5 min. Moreover, Gram positive pathogens have been shown to resist to all treatment trends more than Gram negative pathogens throughout this experiment. Regardless of the different dipping temperatures, concentrations, and times, FA treatment was more effective than treatment with SAEW for reduction of foodborne pathogens. This study demonstrated that application of FA in food systems may be useful as a method for inactivation of foodborne pathogens.

15.
J Food Prot ; 77(1): 23-31, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24405995

ABSTRACT

This study was conducted to investigate the disinfection efficacy of hurdle treatments (thermosonication plus slightly acidic electrolyzed water [SAcEW]) and to develop a model for describing the effect of storage temperatures (4, 10, 15, 20, 25, 30, and 35°C) on the growth of Escherichia coli O157:H7 on fresh-cut kale treated with or without (control) thermosonication combined with SAcEW. The hurdle treatments of thermosonication plus SAcEW had strong bactericidal effects against E. coli O157:H7 on kale, with approximately 3.3-log reductions. A modified Gompertz model was used to describe growth parameters such as specific growth rate (SGR) and lag time (LT) as a function of storage temperature, with high coefficients of determination (R(2) > 0.98). SGR increased and LT declined with rising temperatures in all samples. A significant difference was found between the SGR values obtained from treated and untreated samples. Secondary models were established for SGR and LT to evaluate the effects of storage temperature on the growth kinetics of E. coli O157:H7 in treated and untreated kale. Statistical evaluation was carried out to validate the performance of the developed models, based on the additional experimental data not used for the model development. The validation step indicated that the overall predictions were inside the acceptable prediction zone and had lower standard errors, indicating that this new growth model can be used to assess the risk of E. coli O157:H7 contamination on kale.


Subject(s)
Brassica/microbiology , Disinfection/methods , Escherichia coli O157/growth & development , Food Handling/methods , Models, Biological , Colony Count, Microbial , Electrolysis , Food Microbiology , Temperature , Water/pharmacology
16.
J Microbiol Biotechnol ; 24(2): 209-16, 2014 Feb 28.
Article in English | MEDLINE | ID: mdl-24169453

ABSTRACT

The efficiency of gamma irradiation (0, 1, 5, 10, 15, 20, and 30 kGy) as a sterilization method of corn samples (30 g) artificially contaminated with Fusarium moniliforme stored at normal condition (25ºC with approximate relative humidity (RH) of 55%) and optimal condition (25ºC with a controlled RH of 97%) was studied. The results showed that the fungal growth and the amount of fumonisin were decreased as the dose of gamma irradiation increased. Gamma irradiation at 1-5 kGy treatment significantly inhibited the growth of F. moniliforme by 1-2 log reduction on corn samples (P < 0.05). Sublethal effect of gamma irradiation was observed at 10-20 kGy doses after storage, and a complete inactivation required 30 kGy. Fungal growth and fumonisin production increased with higher humidity and longer storage time in all corn samples. This study also demonstrated that there was no strict correlation between fungal growth and fumonisin production. Storage at normal condition significantly resulted in lower growth and fumonisin production of F. moniliforme as compared with those stored at optimal condition (P < 0.05). Gamma irradiation with the dose of ≥ 5 kGy followed by storage at normal condition successfully prolonged the shelf life of irradiated corns, intended for human and animal consumptions, up to 7 weeks.


Subject(s)
Food Irradiation , Fumonisins/metabolism , Fusarium/growth & development , Fusarium/radiation effects , Gamma Rays , Sterilization/methods , Zea mays/microbiology , Edible Grain/microbiology , Food Contamination , Fusarium/metabolism
17.
Article in English | WPRIM (Western Pacific) | ID: wpr-77360

ABSTRACT

OBJECTIVES: Aluminum step wedge (ASW) equivalent radiodensity (eRD) has been used to quantify restorative material's radiodensity. The aim of this study was to evaluate the effects of image acquisition control (IAC) of a digital X-ray system on the radiodensity quantification under different exposure time settings. MATERIALS AND METHODS: Three 1-mm thick restorative material samples with various opacities were prepared. Samples were radiographed alongside an ASW using one of three digital radiographic modes (linear mapping (L), nonlinear mapping (N), and nonlinear mapping and automatic exposure control activated (E)) under 3 exposure time settings (underexposure, normal-exposure, and overexposure). The ASW eRD of restorative materials, attenuation coefficients and contrasts of ASW, and the correlation coefficient of linear relationship between logarithms of gray-scale value and thicknesses of ASW were compared under 9 conditions. RESULTS: The ASW eRD measurements of restorative materials by three digital radiographic modes were statistically different (p = 0.049) but clinically similar. The relationship between logarithms of background corrected grey scale value and thickness of ASW was highly linear but attenuation coefficients and contrasts varied significantly among 3 radiographic modes. Varying exposure times did not affect ASW eRD significantly. CONCLUSIONS: Even though different digital radiographic modes induced large variation on attenuation of coefficient and contrast of ASW, E mode improved diagnostic quality of the image significantly under the under-exposure condition by improving contrasts, while maintaining ASW eRDs of restorative materials similar. Under the condition of this study, underexposure time may be acceptable clinically with digital X-ray system using automatic gain control that reduces radiation exposure for patient.


Subject(s)
Humans , Aluminum , Radiographic Image Enhancement
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