Real-Time Monitoring the Effects of Storage Conditions on Volatile Compounds and Quality Indexes of Halal-Certified Kimchi during Distribution Using Electronic Nose.

The food logistics system is an essential sector for maintaining and monitoring the safety and quality of food products and becoming more crucial, especially during and after the pandemic of COVID-19. Kimchi is a popular traditional fermented food originally from Korea and easily changes because of the storage conditions. This study aims to evaluate the effects and the contributions of temperature to volatile compounds, quality indexes, and the shelf life of Halal-certified Kimchi, and to identify alcohol and find the correlation between the identified variables using an electronic nose and conventional method with the integration of multivariate analysis. Thirty-two volatile compounds (VOCs) were detected and correlated with pH, titratable acidity (TA), and lactic acid bacteria (LAB) counts during storage time. Ethanol was also found in the ripened Kimchi and possibly became the critical point of halal Kimchi products besides total acidity, pH, and LAB. Furthermore, the correlation between pH and benzaldehyde, titratable acidity and 3-methylbutanoic acid, and among lactic acid bacteria with ethanol, acetic acid, ethyl acetate, and 3-methylbutanoic acid properly can be used as a given set of variables in the prediction of food quality during storage and distribution.

Development of Dynamic Model for Real-Time Monitoring of Ripening Changes of Kimchi during Distribution.

This study describes the development of a method for predicting the ripening of Kimchi according to temperature to provide information on how the ripening of Kimchi changes during distribution. Various Kimchi quality factors were assessed according to temperature and time. The acidity (lactic acid %) was selected as a good freshness index, as it is dependent on temperature and correlates strongly with the sensory quality evaluation. Moreover, it is easy to measure and reproducible in the field. The maximum value of acidity in the stationary phase was observed to increase with the storage temperature. A predictive model was developed using the Baranyi and Roberts and Polynomial models to mathematically predict the acidity. A method using the mean kinetic temperature (MKT) was proposed. The accuracy of the model using the MKT was high. It was confirmed that there is no great variation in the maximum acidity, as MKT does not change much if the temperature changes in the stationary phase where the maximum acidity is constant. This study provides important information about the development of models to predict changes in food quality index under fluctuating temperature environments. The developed kinetic model uniquely treated the quality index at the stationary phase as a function of MKT. The predictions using the food temperature histories could help suppliers and consumers make a reasonable decision on the sales, storage, and consumption of foods. The developed model could be applied to other products such as beef for which the quality index at the stationary phase also changes with temperature histories.

Freshness-based real-time shelf-life estimation of packaged chicken meat under dynamic storage conditions.

The current study was performed to develop dynamic quality and shelf-life prediction models using selected index for packaged chicken meat during storage. Generally, the results showed that meat deterioration, with respect to the different quality indices considered in the investigation, proceeds with increasing temperature and storage time. Highly significant (P ≤ 0.01) correlations were obtained between TPC (total plate count) and SI (sensory index) (r = -0.94 to -0.97), coliforms and SI (r = -0.89 to -0.95), and LAB (lactic acid bacteria) and SI (r = -0.93 to -0.98). However, only the microbiological spoilage regarding TPC, whose values ranged from 7.0 to 8.0 log CFU/g under all investigated temperature conditions, were in compliance with the end of sensory shelf-life defined at SI = 5. To develop dynamic quality prediction model, 4 isothermal (0, 4, 10, and 15°C) experiments in 2 batches were performed for TPC evaluation. Growth data were fitted in the Baranyi and Roberts and quadratic polynomial model as the primary and secondary models, respectively. The model was validated under dynamic conditions (0-8°C scenario with periodic 12-h changes). The accuracy and bias factors were estimated to be 1.045 and 0.991 for fluctuating conditions and 1.016 and 1.015 for real-time conditions, respectively, suggesting good applicability of the model. The remaining shelf-life estimation model developed based on mean kinetic temperature showed an even decrease of shelf-life under dynamic conditions in time. The developed model scan can be used for effective monitoring of packaged chicken meat freshness and shelf-life during distribution with temperature fluctuation.

Kinetic modeling impacts of relative humidity, storage temperature, and air flow velocity on various indices of hen egg freshness.

Storage experiments were conducted to study the impacts of the environmental factors (temperature (T) (°C), relative humidity (RH) (%), and air flow velocity (VEL) (m/s)) on the hen egg quality indices and to develop kinetic model(s) for freshness prediction. VEL had negligible effect on relative weight loss (RWL). All factors had significant effect on Haugh unit (HU) but only T impacted S-ovalbumin content (SO). Fitted regression lines for the RWL and the HU had determination coefficient (R2) of 0.996 and 0.95, respectively. The HU equation reflected impacts of all factors, and the impact of temperature shift-up increases the HU decrease, where the impact decreases with RH and increases with flow velocity. Kinetic model for SO was developed using isothermal (5, 10, 20, 25, and 28.5°C) conditions and validated under dynamic (10 to 20 and 10 to 28.5°C) conditions. The accuracy and bias factor values were 1.091 and 0.917 at 10 to 20°C and 1.206 and 1.204 at 10 to 28.5°C, respectively, which indicates that the SO model performed well. The SO model can be used along with the HU model (as the HU model can reflect the combined effect of temperature, humidity, and air flow velocity) to predict hen egg freshness at 5 to 28.5°C storage condition.

Stabilization of the lumbar spine by spinal muscle forces producing compressive follower loads: 3-dimensional computational study.

Axial compressive loads whose direction changes along the spinal curvature (so called compressive follower loads (CFLs)) was postulated as a normal physiological load in the lumbar spine in the literature. Computational analyses were conducted in this study using finite element and optimization models of the spinal system incorporating 244 fascicles of back muscles. It was feasible to find optimum solutions for spinal muscle forces generating CFLs in the lumbar spine in 3-D postures of neutral standing, flexion 40°, extension 10°, axial rotation 10°, or lateral bending 30°. FE analyses demonstrated that the lumbar spine can be in a stable condition not under all CFL generating muscle forces but under those producing CFLs along a curve parallel to the spinal curvature located in the vicinity of the base spinal curve constructed by connecting the geometrical centers of the vertebral bodies. It was also possible to estimate the stable range of the relative location of such CFL curve to the base spinal curve. These results suggest that the lumbar spine in various 3-D postures can be stabilized by spinal muscles that generate CFLs in the spine, which at least in part supports the hypothesis of CFLs as a physiological load in the lumbar spine. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3004-3012, 2018.

Reduction of Salmonella enterica on the surface of eggshells by sequential treatment with aqueous chlorine dioxide and drying.

The synergistic effects of sequential treatments with chlorine dioxide (ClO2) and drying in killing Salmonella enterica on the surface of chicken eggshells were investigated. Initial experiments were focused on comparing lethalities of sodium hypochlorite (NaOCl) and ClO2. Eggs surface-inoculated with S. enterica in chicken feces as a carrier were immersed in water, NaOCl (50 or 200 µg/mL), or ClO2 (50 or 200 µg/mL) for 1 or 5 min. For 1-min treatments, lethal activities of sanitizers were not significantly different (P>0.05). However, after treatment with ClO2 for 5 min, reductions of S. enterica were significantly greater (P≤0.05) than reductions after treatment with water or NaOCl. The effect of treatment of eggs with ClO2 or NaOCl, followed by drying at 43% relative humidity and 25 °C for 24 and 48 h, were determined. Populations of S. enterica decreased during drying, regardless of the type of sanitizer treatment. ClO2 treatment, compared to water or NaOCl treatments, resulted in additional reductions of ca. >1.3 log CFU/egg during drying. This indicates that sequential treatments with ClO2 and drying induced synergistic lethal effects against S. enterica on the surface of eggshells. These observations will be useful when selecting a sanitizer to control S. enterica on the surface of eggshells and designing an effective egg sanitization system exploiting the synergistic lethal effects of sanitizer and drying.

Fate of mesophilic aerobic bacteria and Salmonella enterica on the surface of eggs as affected by chicken feces, storage temperature, and relative humidity.

We compared the microbiological quality of chicken eggshells obtained from a traditional wholesale market and a modern supermarket. We also determined the survival and growth characteristics of naturally occurring mesophilic aerobic bacteria (MAB) and artificially inoculated Salmonella enterica on eggshells under various environmental conditions (presence of chicken feces, temperature [4, 12, or 25 °C], and relative humidity [RH; 43 or 85%]). The populations of MAB, coliforms, and molds and yeasts on eggshells purchased from a traditional wholesale market were significantly (P ≤ 0.05) higher than those from a modern supermarket. In the second study, when we stored uninoculated eggs under various storage conditions, the population of MAB on eggshells (4.7-4.9 log CFU/egg) remained constant for 21 days, regardless of storage conditions. However, when eggshells were inoculated with S. enterica and stored under the same conditions, populations of the pathogen decreased significantly (P ≤ 0.05) under all tested conditions. Survival of S. enterica increased significantly (P ≤ 0.05) in the presence of feces, at low temperatures, and at low RH. These observations will be of value when predicting the behavior of microorganisms on eggshells and selecting storage conditions that reduce the populations of S. enterica on eggshells during distribution.

Behaviour of Aspergillus flavus and Fusarium graminearum on rice as affected by degree of milling, temperature, and relative humidity during storage.

We investigated the survival and growth patterns of Aspergillus flavus and Fusarium graminearum, as well as mycotoxin production, on Korean rice as affected by the degree of milling (rough, brown, and white rice) and storage conditions (21 °C/85% relative humidity [RH], 21 °C/97% RH, and 30 °C/85% RH). When rice was stored at 21 °C/85% RH, the population of A. flavus remained constant and aflatoxin was not produced, regardless of the degree of milling. At 21 °C/97% RH and 30 °C/85% RH, the populations of A. flavus increased significantly (P ≤ 0.05) and aflatoxins were produced. The highest population of A. flavus and highest amount of aflatoxin B1 were observed on brown rice stored at 21 °C/97% RH. For F. graminearum, when stored at 85% RH, the populations were reduced to less than a detectable level (5 CFU/g of rice) within 120 days and no deoxynivalenol (DON) was produced, regardless of the degree of milling and storage temperature. However, at 21 °C/97% RH, the population of F. graminearum increased significantly (P ≤ 0.05) and DON was produced on all types of rice. Findings from this study provide insights concerning storage conditions necessary to prevent growth and mycotoxin production by A. flavus and F. graminearum on Korean rice with different degrees of milling.

Feasibility of compressive follower load on spine in a simplified dynamic state: a simulation study.

This study investigated that the spinal MFs can create compressive follower loads (CFLs) in the lumbar spine in a dynamic state. Three-dimensional optimization and finite element (FE) models of the spinal system were developed and validated using reported experimental data. An optimization analysis was performed to determine the MFs that create CFLs in the lumbar spine in various sagittal postures from 10° extension to 40° flexion. Optimization solutions for the MFs, CFLs, and follower load path (FLP) location were feasible for all studied postures. The FE predictions demonstrated that MFs which created CFLs along the base spinal curve connecting the geometrical centers or along a curve in its vicinity (within anterior or posterior shift by 2 mm) produced stable deformation of the lumbar spine in the neutral standing and flexed postures, whereas the MFs which created the smallest CFLs resulted in unstable deformation. For extended postures, however, finding CFLs creating MFs that produce stable deformation of the extended spine was not possible. The results of this study support the hypothesis that the spinal muscles may stabilize the spine via the CFL mechanism.

Bacillus cereus and Bacillus thuringiensis spores in Korean rice: prevalence and toxin production as affected by production area and degree of milling.

We determined the prevalence of and toxin production by Bacillus cereus and Bacillus thuringiensis in Korean rice as affected by production area and degree of milling. Rough rice was collected from 64 farms in 22 agricultural areas and polished to produce brown and white rice. In total, rice samples were broadly contaminated with B. cereus spores, with no effect of production area. The prevalence and counts of B. cereus spores declined as milling progressed. Frequencies of hemolysin BL (HBL) production by isolates were significantly (P ≤ 0.01) reduced as milling progressed. This pattern corresponded with the presence of genes encoding the diarrheal enterotoxins. The frequency of B. cereus isolates positive for hblC, hblD, or nheB genes decreased as milling progressed. Because most B. cereus isolates from rice samples contained six enterotoxin genes, we concluded that B. cereus in rice produced in Korea is predominantly of the diarrheagenic type. The prevalence of B. thuringiensis in rice was significantly lower than that of B. cereus and not correlated with production area. All B. thuringiensis isolates were of the diarrheagenic type. This study provides information useful for predicting safety risks associated with B. cereus and B. thuringiensis in rough and processed Korean rice.

Fate of Bacillus cereus and naturally occurring microbiota on milled rice as affected by temperature and relative humidity.

We studied the survival and growth patterns of Bacillus cereus, mesophilic aerobic bacteria (MAB), and molds and yeasts (MY) on rough and milled brown and white Korean rice stored at 12 and 21 °C and 43, 68, and 85% relative humidity (RH) for up to 24 wk. The initial populations of MAB present on rough rice, brown rice, and white rice were 7.7, 5.7, and 3.3 log CFU/g, respectively, and remained constant or decreased (P ≤ 0.05) by 0.7-1.8 log CFU/g during storage. The initial populations of B. cereus on the three types of laboratory-inoculated rice were 3.1-3.8 log CFU/g and remained constant (P > 0.05) during storage, regardless of degree of milling, storage temperature, and RH. The initial populations of MY on rough rice, brown rice, and white rice were 6.2, 4.2, and 2.1 log CFU/g, respectively. At 12 °C and 85% RH, the MY increased significantly (P ≤ 0.05) only on brown rice; however, at 21 °C and 85% RH, MY increased (P ≤ 0.05) on all types of rice during storage. These observations will be useful when assessing conditions affecting survival of B. cereus and determining environmental conditions necessary to prevent growth of potentially mycotoxigenic molds on various types of milled rice during storage.

Effect of Pre-treatment and Storage Conditions on the Quality Characteristics of Ginger Paste.

This study was performed to investigate the effects of pre-treatment and storage temperature and periods on the quality characteristics of ginger paste. The pH of the ginger paste remained constant during room temperature storage but increased with prolonged refrigerated storage periods. During five months of frozen storage, regardless of pre-treatment, the pH of most of the samples decreased slightly and then remained constant. In the color value of ginger paste stored at room temperature, the samples with and without chemical additives changed in color more prominently than fermented or pasteurized samples. Intriguingly, the color value for samples containing chemical additives changed more dramatically when stored under refrigerated conditions. However, the L, a, and b values of samples stored under frozen storage conditions did not change even after ten months. Most of the samples contained glucose and fructose, except for the fermented samples. The free sugar content of samples slowly decreased with increasing storage periods, while the organic acid content generally decreased also, regardless of sample type. Depending on pre-treatment and storage temperature, the gingerol content of the samples was either retained or decreased with prolonged storage time.

Biomechanical comparison of anterior, posterior, and circumferential fixation after one-level anterior cervical corpectomy in the human cadaveric spine.

STUDY DESIGN: In vitro biomechanical study of cadaveric cervical spine. OBJECTIVE: To compare the rigidity of the cervical spine after anterior, posterior, and circumferential fixation after 1-level corpectomy, and evaluate the effects of the integrity of the facet capsules and posterior ligaments (PL). SUMMARY OF BACKGROUND DATA: Anterior cervical corpectomy is commonly used for decompression of the spinal canal in the treatment of different pathologic conditions. The effect of the integrity of the facet capsules and PLs on the biomechanical stability provided by anterior, posterior, or circumferential fixation following 1-level corpectomy has not been investigated. METHODS: Nine cadaveric cervical spines were potted rostrally at C2, and caudally at T1-T2, and were tested in 6 directions with pure moment application, in 5 conditions: In the intact spine, after a C5 corpectomy and anterior fixation, after anterior fixation and disruption of the C4-C5 and C5-C6 facet capsules and PL, after circumferential fixation, and after posterior fixation alone without anterior cage. Angular motion of C4 relative to C6 was measured. RESULTS: Despite C5 corpectomy, anterior grafting and plate fixation was more rigid than the intact spine with all loads in flexion, at loads of 0.5 Nm and 1.0 Nm in right axial rotation and right lateral bending, and at all loads in left lateral bending. Posterior ligamentous disruption increased motion in the coronal and axial planes, but not in the sagittal plane. Circumferential instrumentation resulted in a significant reduction in motion of the spine compared with anterior instrumentation in both the coronal and axial planes but not in the sagittal plane. Posterior fixation without anterior cage failed to limit cervical spine motion in the sagittal plane, but was restrictive in axial rotation and lateral bending when compared with circumferential fixation. CONCLUSION: After C5 corpectomy, with intact PLs and facet capsules, anterior instrumentation is sufficient for spinal stabilization as the resultant construct is more rigid than the intact state. In the presence of C5 corpectomy with PL and bilateral facet capsule disruption, anterior plus posterior instrumentation is more rigid than anterior instrumentation alone in the axial and coronal planes and more rigid than posterior instrumentation without anterior cage in the sagittal plane.

Spinal muscles can create compressive follower loads in the lumbar spine in a neutral standing posture.

The ligamentous spinal column buckles under compressive loads of even less than 100N. Experimental results showed that under the follower load constraint, the ligamentous lumbar spine can sustain large compressive loads without buckling, while at the same time maintaining its flexibility reasonably well. The purpose of this study was to investigate the feasibility of follower loads produced by spinal muscles in the lumbar spine in a quiet standing posture. A three-dimensional static model of the lumbar spine incorporating 232 back muscles was developed and utilized to perform the optimization analysis in order to find the muscle forces, and compressive follower loads (CFLs) along optimum follower load paths (FLPs). The effect of increasing external loads on CFLs was also investigated. An optimum solution was found which is feasible for muscle forces producing minimum CFLs along the FLP located 11 mm posterior to the curve connecting the geometrical centers of the vertebral bodies. Activation of 30 muscles was found to create CFLs with zero joint moments in all intervertebral joints. CFLs increased with increasing external loads including FLP deviations from the optimum location. Our results demonstrate that spinal muscles can create CFLs in the lumbar spine in a neutral standing posture in vivo to sustain stability. Therefore, its application in experimental and numerical studies concerning loading conditions seems to be suitable for the attainment of realistic results.