Effect Of Storage Temperature Research Articles

Effect of storage temperature on chilling injury of ‘Cheongdobansi’, an astringent persimmon of Korea

Effect of storage temperature on chilling injury of ‘Cheongdobansi’, an astringent persimmon of Korea

Effect of storage temperature and produce type on the survival or growth of Listeria monocytogenes on peeled rinds and fresh-cut produce.

Whole and fresh-cut produce are minimally processed and susceptible to microbial contamination. This study evaluated the survival or growth of L. monocytogenes on peeled rinds, and fresh-cut produce at different storage temperatures. Fresh-cut fruits and vegetables, including cantaloupe, watermelon, pear, papaya, pineapple, broccoli, cauliflower, lettuce, bell pepper, and kale (25 g pieces) were spot inoculated with 4 log CFU/g of L. monocytogenes and stored at 4 or 13°C for 6 days. Cantaloupe and bell pepper rind disks (20 cm2), mimicking whole produce were inoculated with low inoculum level (4 log CFU/mL) and high inoculum level (6 log CFU/mL) and stored at 24°C up to 8 days and 4°C up to 14 days, respectively. L. monocytogenes counts on fresh-cut pear samples stored at 4°C increased significantly by 0.27 log CFU/g. However, Listeria levels on kale (day 4), cauliflower (day 6), and broccoli (day 2) were significantly reduced by 0.73, 1.18, and 0.80 log CFU/g, respectively, at 4°C. At 13°C, the bacterial counts increased significantly after a day of storage on fresh-cut watermelons (increasing by 1.10 log CFU/g) and cantaloupes (increasing by 1.52 log CFU/g). Similar increases were observed on pears (1.00 log CFU/g), papayas (1.65 log CFU/g), and green bell peppers (1.72 log CFU/g). Pineapple samples did not support the growth of L. monocytogenes at 13°C with a significant reduction of 1.80 log CFU/g by day 6. L. monocytogenes levels significantly increased in fresh-cut lettuce at 13°C but remained stable on kale, cauliflower, and broccoli after 6 days of storage. Stable population was observed also on cantaloupe rinds up to 8 days at 24°C. While on the outer surface of bell peppers, the population level decreased below the detectable limit of the test (10 CFU/20 cm2) after 14 days of storage at 4°C. The results demonstrated variable survival behavior of L. monocytogenes on fresh-cut produce with produce type and storage temperature.

Effect of Different Storage Temperatures on Quality Changes of Ready-to-Eat Fresh-cut Fruit Trays

Objective: To ensure the storage quality and food safety of ready-to-eat fresh-cut fruits trays, the growth changes of microbial hygiene indicator bacteria (colony count, coliform, mold yeast) in ready-to-eat fresh-cut fruit trays under different temperature conditions were analyzed to assess their food safety risks and to seek the optimal storage time. Methods: The tropical fruits (dragon fruit, mango, papaya, watermelon, sainfoin) were washed, peeled and cut into pieces to produce ready-to-eat fresh-cut fruit trays, which were stored at different temperatures (6°C, 10°C and 15°C), sampled regularly to detect the number of microbial indicators and plotted the growth curves using the national standards for food microbiological testing. Results: It showed that under the storage environment of 6°C, the growth trend of microbial hygiene indicators was not obvious, the contamination level was low, the sensory changes were small, the preservation effect was good, and the shelf life could be within 24h; under the environment of 10°C, the growth trend of hygiene indicators showed a gradual increase, and the sensory quality changed more after 10h, and the best storage time was within 10h. The best storage time is 10h; while 15°C environment, the growth of hygienic indicator bacteria is too fast, sensory in 6h after the color becomes lighter, oozing juice, so 15°C is not recommended for long time storage of ready-to-eat fresh cut fruit plate, in 6h consumption is a safer preservation time frame.

Observational study of Lactuca sativa L quality during storage

Leafy vegetables like lettuce (Lactuca sativa L) are prone to deteriorate in a short of time. Therefore, a proper storage is crucial to preserve the freshness of vegetables. Hence, the study is done to determine the effect of different storage temperature on lettuce quality at 5°C and room temperature to see quality changes over time. The changes in the chemical compound and physical appearance of lettuce throughout the storage process is collected. The observation was conducted in 15 days with 3-day intervals. The observational parameters are weight, sucrose level, chlorophyll, leaf colour, wilting, browning, taste, crunchiness and overall visual as the parameter. The result shows that, lettuce stored in refrigerator has longer shelf life and still consumable. At room temperature, the leaf starts to deteriorate after Day-6 while at 5°C, the lettuce quality start to drop after Day-12. Higher temperature will make the colour, wiltingness of the salad and browning are more affected than other variables. It is suggested that the lettuce is kept under lower temperature to extend its shelf life.

Harmonization of OF LC‐MS oxylipin analysis to investigate lipid mediator formation and signaling in immune cells

The oxidation products of polyunsaturated fatty acids (PUFA) ‐ oxylipins ‐ are formed via enzymatic conversion by cyclooxygenases, lipoxygenases (LOX) and cytochrome P450 monooxygenases or by autoxidation. Together with multiple PUFA substrates this leads to a large variety of oxylipins, whose physiological functions are ‐ besides those of well‐studied prostaglandins and leukotrienes ‐ little understood. The interplay of several PUFA‐oxidizing enzymes, as in the case of multihydroxylated oxylipins, additionally complicates the investigation of their biosynthesis. Due to regulatory crosstalk and complex interactions of different oxylipin classes during physiological processes, such as inflammation, a study of the whole oxylipin profile rather than individual compounds is necessary. Therefore, in order to understand the functions of these lipid mediators potent and reliable biochemical methods and (molecular) biological models are required, in combination with sensitive and sound preanalytical, analytical and post‐analytical procedures for their investigation.The first part of this thesis investigated the relevance of harmonizing such analytical methods for the quantitative determination of oxylipins in biological samples. Based on the outcome of an international laboratory comparison, comparable and reproducible results were obtained across independent laboratories when these harmonized methods were used for sample preparation and analysis by means of liquid chromatography coupled with tandem mass spectrometry. The examination of the effect of different storage times and temperatures as a parameter of pre‐analytics demonstrated that oxylipin levels in plasma samples are robust to long‐term storage and, furthermore, to minor variations during plasma generation. As accurate quantification of oxylipin concentrations rises and falls with the quality of analytical standards, a strategy for the verification of oxylipin standard concentrations with mass‐ spectrometry and UV spectroscopy based approaches using certified standard compounds was presented.In the second part of the thesis the established methods were applied to study the biosynthesis of oxylipins in immune cells with a special attention to the involved LOX. Stimulation of primary human M2‐like macrophages with the liver X receptor (LXR) agonist T09 led to a massive induction of ALOX15 gene expression and thus, 15‐LOX abundance and activity. Cholesterol derivatives were identified as potent endogenous ligands of LXR yielding increased 15‐LOX abundance and activity. The examination of 5‐LOX induced synthesis of multihydroxylated metabolites through supplementation of neutrophils with 15‐HETE, 18‐ HEPE and 17‐HDHA primary leads to formation of double oxygenated oxylipins. In intact cells 5‐LOX preferred DHA‐derived 17‐HDHA as substrate, whereas upon cell integrity destruction the formation of 15‐HETE derived multihydroxylated oxylipins increased.With the combination of harmonized protocols for sampling and analysis this thesis sets the basis for the reliable quantification of oxylipins. The use of the optimized methodologies allowed to further characterize regulatory pathways of the ARA cascade in human immune cells, contributing to a more thorough understanding of inflammation regulation.

The antioxidant capacity and nutrient composition characteristics of lotus (Nelumbo nucifera Gaertn.) seed juice and their relationship with color at different storage temperatures.

The effects of different storage temperatures on the nutritional quality, color, and antioxidant capacity of lotus seed juice and the correlations between various physicochemical indices and antioxidant capacity during storage were investigated in this study. The results showed that the overall retention rate of various nutrients and antioxidant activity in lotus seed juice under low-temperature storage was better than that under 37°C storage. Meanwhile, temperature had a significant effect on increasing the browning of lotus seed juice and the change in L*. The results of Pearson correlation and redundancy analysis (RDA) showed that the reduction in antioxidant activity in lotus seed juice aggravated the browning index of the system at high temperatures. The color changes in the system were closely related to the clarity of lotus seed juice and aging of starch at low temperatures.

Effect of Different Packaging and Frozen Storage Temperature on the Muscle Protein Fractionation of Frozen Broiler Meat

Effect of Different Packaging and Frozen Storage Temperature on the Muscle Protein Fractionation of Frozen Broiler Meat

Formulating the best Helbat: A Tigraian semi-liquid fasting condiment

Helbat (hl'bət), a fasting semi-liquid condiment, is a popular indigenous traditional fermented product in Tigrai (a.k.a. Tigray), Ethiopia. It is formulated using Vicia faba flour prepared from mildly roasted dry beans. Despite its dietary, nutritional, religious, and cultural significance, the condiment is yet not exposed to scientific study. Hence, this research was carried out to: (a) ascertain the best faba bean variety for preparing high quality Helbat, (b) develop the formulation and preparation protocol of high quality Helbat, (c) determine the effects of fermentation and storage temperature and time on the physicochemical characteristics, proximate and mineral compositions, microbiological properties, and sensory qualities of Helbat, and (d) determine the shelf life of Helbat as the function of storage time and temperature. To this end, three faba bean varieties used in preparing Helbat as well as fermenting and stored Helbat products were studied using standard physicochemical, microbiological, and sensory evaluation procedures. Quantitative data were processed using inferential statistical methods and mean (±SD) values were compared at a priori set p-value of ≤0.05. The study showed that: (a) the best faba bean variety for making high quality Helbat was Megulat; (b) the best Helbat formulation constituted 400 wt units of bean flour, 7 wt units of garlic, 6 wt units of ginger, 5 wt units fenugreek, 5 wt units of corrorima, 8 wt units of red pepper, and 3 wt units of black mustard; (c) the best Helbat formulation was nutritionally rich to supplement fasting consumers with proteins, fats, and minerals; (d) the Helbat formulation remained safe for up to eight weeks while maintaining its attractive sensory qualities when stored at 11–15 °C, and (e) increasing the fermentation and storage times led to changes in its physicochemical properties (i.e., temperature, pH, total titratable acidity, and total soluble solute) and depletion of many nutritionally vital components such as fats, proteins, and minerals. Thus, unless production and storage conditions are somehow modified, Helbat needs to be consumed fresh after three to seven days of fermentation. But further research may be required to make this recommendation conclusively. Exploring into its antioxidant properties and lactic acid bacteria (LAB) may highlight its qualities further.

Application of strigolactone analogs in storage of Gastrodia elata

This study explored the preservation effect of strigolactone analogs on Gastrodia elata tubers and screened out the suitable preservation measures of G. elata to provide a safer and more effective method for its storage and preservation. Fresh G. elata tubers were treated with 7FGR24, 2,4-D isooctyl ester, and maleic hydrazide, respectively. The growth of flower buds, the activities of CAT, and MDA, and the content of gastrodin and p-hydroxybenzyl alcohol were measured to compare the effects of different compounds on the storage and preservation of G. elata. The effects of different storage temperatures on the preservation of 7FGR24 were compared and analyzed. The gibberellin signal transduction receptor gene GeGID1 was cloned, and the effect of 7FGR24 on the expression level of GeGID1 was analyzed by quantitative polymerase chain reaction(qPCR). The toxicity of the G. elata preservative 7FGR24 was analyzed by intragastric administration in mice to evaluate its safety. The results showed that compared with 2,4-D isooctyl ester and maleic hydrazide, 7FGR24 treatment had a significant inhibitory effect on the growth of G. elata flower buds, and the CAT enzyme activity of G. elata was the highest, indicating that its preservation effect was stronger. Different storage temperatures had different effects on the preservation of G. elata, and the preservation effect was the strongest at 5 ℃. The open reading frame(ORF) of GeGID1 gene was 936 bp in length, and its expression level was significantly down-regulated after 7FGR24 treatment, indicating that 7FGR24 may inhibit the growth of flower buds by inhibiting the gibberellin signal of G. elata, thereby exerting a fresh-keeping effect. Feeding preservative 7FGR24 had no significant effect on the behavior and physiology of mice, indicating that it had no obvious toxicity. This study explored the application of the strigolactone analog 7FGR24 in the storage and preservation of G. elata and preliminarily established a method for the storage and preservation of G. elata, laying a foundation for the molecular mechanism of 7FGR24 in the storage and preservation of G. elata.

Relationship between oxygen partial pressure and inhibition of cell aggregation of human adipose tissue-derived mesenchymal stem cells stored in cell preservation solutions

IntroductionThis study investigated the storage conditions under which cell aggregation occurs and the conditions that inhibit cell aggregation when human adipose tissue-derived mesenchymal stem cells (hADSCs) are stored in lactated Ringer’s solution (LR) supplemented with 3% trehalose and 5% dextran 40 (LR-3T-5D). MethodsWe first examined the effects of storage temperature and time on the aggregation and viability of hADSCs stored in LR and LR-3T-5D. The cells were stored at 5 °C or 25 °C for various times up to 24 h. We then evaluated the effects of storage volume (250-2,000 μL), cell density (2.5-20 × 105 cells/mL), and nitrogen gas replacement on aggregation, oxygen partial pressure (pO2), and viability of hADSCs stored for 24 h at 25 °C in LR-3T-5D. ResultsWhen stored in LR-3T-5D, viability did not change under either condition compared with pre-storage, but the cell aggregation rate increased significantly with storage at 25 °C for 24 h (p<0.001). In LR, the aggregation rate did not change under either condition, but cell viability decreased significantly after 24 h at both 5 °C and 25 °C (p < 0.05). The cell aggregation rates and pO2 tended to decrease with increasing solution volume and cell density. Nitrogen gas replacement significantly decreased the cell aggregation rate and pO2 (p < 0.05). However, there were no differences in viability among cells stored under conditions of different storage volumes, densities, and nitrogen gas replacement. ConclusionsAggregation of cells after storage at 25 °C in LR-3T-5D may be suppressed by increasing the storage volume and cell density as well as by incorporating nitrogen replacement, which lowers the pO2 in the solution.

Variability in proximate and mineral compositions of yolk and albumen in eggs kept under different storage conditions

This investigation evaluated the effects of storage length and temperature on the proximate and mineral compositions of yolk and albumen (white) of chicken eggs. A total of 720 eggs were used in a 4 X 2 factorial experiment consisting of four (0, 7, 14 and 21) storage days and two (room and cold) storage temperatures. Data obtained were subjected to ANOVA. The results showed no significant effect of storage length on crude protein and ash contents of the egg parts whereas carbohydrate increased significantly with increasing storage length. Also, protein and fat contents of the yolk were largely influenced (p&lt;0.05) by storage temperature but nutrients in the albumen did not differ significantly between the two storage temperatures. On the other hand, mineral compositions of the egg components did not vary noticeably by storage temperature but storage length influenced some minerals considerably. It was noted that variations in proximate and mineral contents of egg yolk and albumen under different storage conditions exist; so, storage conditions (length and temperature) must be given much attention when keeping eggs prior to consumption in order to ensure nutrient quality.

Effects of storage temperature, storage time, and hemolysis on the RNA quality of blood specimens: A systematic quantitative assessment

IntroductionBlood samples are the most common biospecimen in biobanks, and RNA from such blood samples is an important material for biomedical research. High-quality RNA is essential for consistent, reliable results. Preanalytical environmental conditions can affect the quality of blood RNA. Here, we carried out a quantitative assessment of the influence of storage temperature, storage time, and hemolysis on the RNA quality of blood specimens in biobanks. MethodsBefore RNA purification, blood samples from volunteers were exposed to 4 °C for 2, 6, 12, 24, or 48 h, 3 days, or 1 week, or exposed to room temperature (22–30 °C) for 1, 2, 6, 12, or 24 h. Hemolyzed samples were collected from laboratory department and some of them were prepared using the freeze-thaw method. After exposure to different preanalytical environmental conditions, the RNA simple Total RNA Kit was used to purify the RNA, following which a NanoDrop™ One and Qsep 100 Bio-Fragment Analyzer were used to assess RNA concentration, purity, and integrity. In addition, a part of the RNA was immediately reverse transcribed into cDNA when it was purified, then the relative expression levels of 18S, ACTB, HIF1α, HMOX1, and MKI67 were determined by real-time quantitative PCR. Finally, 30 blood samples were collected from the surplus samples in our laboratory department to assess their RNA quality without knowledge of their storage conditions (duration/temperature). ResultsFor blood samples stored at 4 °C, there was a significant difference between the RNA integrity after 1 week compared to after 2 h. For blood samples stored at room temperature (22–30 °C), the RNA integrity was also significantly different at 6 h and 0 h. Hemolysis caused by freeze-thawing severely affected RNA quality, whereas clinical hemolysis generally produced no significant effects. Moreover, expression of 18S, ACTB, HIF1α, HMOX1, and MKI67 in whole blood stored under different conditions showed irregular changes, suggesting that preservation conditions are also important for gene expression. ConclusionRNA integrity was qualified for blood samples stored at 4 °C for up to 72 h or at room temperature (22–30 °C) for up to 2 h. Hemolysis usually does not affect the RNA quality of blood samples unless the hemolysis method damages leukocytes.

Effects of cold storage temperature on thermoreversible aging in heavily oxidized asphalt binders

In order to better understand the thermoreversible aging characteristics of asphalt after heavy oxidation, six selected heavily oxidized asphalt containing different proportions of C20H42 are subjected to extended bending beam rheometer (ExBBR) tests, while modulated differential scanning calorimetry (MDSC) and atomic force microscope (AFM) are also performed on the asphalt. The results indicate that the introduction of heavy oxidation will not only affect the low temperature properties of the asphalt but also its thermoreversible aging characteristics, but this effect will receive an influence of the storage temperature. This is due to the increase in viscosity of the asphalt after heavy oxidation, which makes it difficult for C20H42 to migrate, while the increase in storage temperature can release the potential of the degree of thermoreversible aging of the asphalt by accelerating the movement of wax molecules. And like C20H42, the grade loss of asphalt blended with C30H62 is different at different storage temperatures and oxidation levels, which proves that for heavily oxidized asphalt, multiple storage temperatures should be selected for testing its grade loss. Combined with thermal and morphological analysis, the introduction of heavy oxidation not only increases the amount of wax precipitation, but also significantly increases the thermoreversible aging of the asphalt by lowering the Tg of the asphalt and forming more perfect crystals during low temperature storage. Finally, by comparing the grade loss due to cold storage and extended oxidation, it can be found that the incorporation of C20H42 will make the asphalt more influenced to physical hardening. Therefore, it is necessary to study the effect of asphalt wax content on the degree of thermoreversible aging of heavily oxidized asphalt.

Deployment analysis of composite thin-walled lenticular tubes with effect of storage time and temperature

Composite Thin-walled Lenticular Tube (CTLT) is increasingly utilized in small satellites missions as a lightweight, foldable, and rollable structural material that facilitates the construction of large deployable systems. The CTLT is initially flattened and coiled around a central hub for storage before launch, during which elastic energy is stored as deformation energy, allowing it to be self-deployed on demand for use in orbit. This work presents a comprehensive investigation into the coiling, storage and deployment behaviors of CTLT that wraps around a central hub. A nonlinear explicit dynamic finite element model was developed with both deformable CTLT and rigid-bodies mechanisms including the central hub and guide rollers, as well as the complex interactions among them. The coiling mechanics characteristics such as stored strain energy and rotational moment were presented and validated against experimental data in the literature. Then, the dynamic deployment behaviors were analyzed in terms of two different deployment methods, namely, controlled deployment and free deployment. The effect of material property change during storage was also discussed through numerical experiments.

Effect of storage temperatures simulating transport conditions of nasopharyngeal swabs on the results of a chemiluminescence immunoassay (CLIA) to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen

PurposeChemiluminescence Immunoassay (CLIA) is high throughput, rapid diagnostic test which has recently come up for the detection of SARS-CoV-2 antigen. The present study evaluated performance of CLIA antigen test in nasopharyngeal swab samples stored at different temperatures for 7 days to simulate the transport conditions and transit time across the country from remote peripheral laboratories to central facilities. Materials and methodsLimit of detection (LOD), sensitivity and specificity of VITROS® SARS-CoV-2 antigen assay was determined using Real-time reverse transcriptase PCR (rRT-PCR) confirmed SARS-CoV-2 positive and negative samples. To detect the effect of storage temperatures on VITROS ®SARS-CoV-2 antigen results, samples were stored at 4 ​°C, 25 ​°C & 37 ​°C for 7 days followed by detection of SARS-CoV-2 nucleocapsid antigen and compared with N-gene rRT-PCR. ResultsThe VITROS® SARS-CoV-2 antigen test was found to have a sensitivity and specificity of 78.9% and 100% respectively with high sensitivity of 88.1% for samples with Ct ​< ​30. The LOD of VITROS assay was equivalent to 3800 copies of RNA per reactions as compared to 72 copies per reaction for rRT-PCR. We observed that more than 80% of samples with <30 Ct values could be detected by VITROS SARS-CoV-2 antigen assay at day 7 even when stored at 37 ​°C. For samples with Ct values between 26 and 30, on day 7 the positivity rate of N-antigen at 4 ​°C was 90.9% and 37 ​°C was 63.6%. ConclusionsCLIA testing can be carried out for the detection of SARS-CoV-2 N-protein in NP-swab samples transported in cold chain even with 7 days transit time, particularly for Ct ​< ​30 samples which represents cases with higher transmissibility. As drop in positivity for VITROS assay was lower as compared to rRT-PCR on day 7 in cold chain-maintained samples, the assay can be useful to screen samples received from remote peripheral areas before performing rRT-PCR.

Optimization of a method for collecting infant and toddler urine for non-target analysis using cotton pads and commercially available disposable diapers.

Urine is an abundant and useful medium for measuring biomarkers related to chemical exposures in infants and children. Identification of novel biomarkers is greatly enhanced with non-targeted analysis (NTA), a powerful methodology for broad chemical analysis of environmental and biological specimens. However, collecting urine in non-toilet trained children presents many challenges, and contamination from specimen collection can impact NTA results. We optimized a caregiver-driven method for collecting urine from infants and children using cotton pads and commercially available disposable diapers for NTA and demonstrate its applicability to various children biomonitoring studies. Experiments were first performed to evaluate the effects of processing method (i.e., centrifuge vs. syringe), storage temperature, and diaper brand on recovery of urine absorbed to cotton pads. Caregivers of 11 children (<2 years) used and retained diapers (with cotton pads) to collect their child's urine for 24 h. Specimens were analyzed via a NTA method implementing an exclusion list of ions related to contamination from collection materials. Centrifuging cotton pads through a small-pore membrane, compared to a manual syringe method, and storing diapers at 4 °C, compared to room temperature, resulted in larger volumes of recovered sample. This method was successfully implemented to recover urine from cotton pads collected in the field; between 5-9 diapers were collected per child in 24 h, and the total mean volume of urine recovered was 44.7 (range 26.7-71.1) mL. NTA yielded a list of compounds present in urine and/or stool that may hold promise as biomarkers of chemical exposures from a variety of sources. Infant and children urine is a valuable matrix for studies of the early life exposome, in that numerous biological markers of exposure and outcome can be derived from a single analysis. Depending on the nature of the exposure study, it may be the case that a simple collection method that can be facilitated by caregivers of young children is desirable, especially when time-integrated samples or large volumes of urine are needed. We describe the process for development and results of an optimized method for urine collection and analysis using commercially available diapers and non-target analysis.

Investigation of average crosslink distance and physicochemical properties of gummy candy during storage: Effect of formulation and storage temperature

Texture is linked to food structure at micro- and macro-levels. The most effective way to manipulate gel texture is to change the number of crosslinks per unit volume. Polymer concentration and type can be changed or the amount of evaporated water can be adjusted to achieve this. Gummy candy is a good food model to investigate texture due to the presence of versatile polymer gelling agents. The estimation of average cross-link distance is a good approach to monitor candy texture. Physicochemical properties are useful indicators showing storage stability. In this study, gummy candies were prepared with different glucose sirup:sucrose ratios (1.1 and 1.5), starch (0% and 1.5%), and gelatin (3% and 6%) concentrations. Texture (hardness), moisture content, water activity (aw), total soluble solids (TSS), and pH were measured. Candies were stored at 10, 20, and 30 °C for 12 weeks and at ambient temperatures of 15–22 °C for 52 weeks. Gelatin concentration, moisture content, storage time, and temperature affected hardness. At 1.5 glucose sirup:sucrose ratio, average cross-link distance decreased after 10 °C storage for 3% gelatin level and it increased after 20 and 30 °C storage for 6% gelatin and 0% starch level; however, it did not change for 15–22 °C storage. Moisture content, aw, TSS, and pH were affected by glucose sirup:sucrose ratio. A Weibullian model was used to express quality changes, and physicochemical indicators did not have an integer kinetic order. Tracking of physicochemical properties and texture with average cross-link distance calculation and modeling is useful for storage stability studies showing the quality of food gel products.

107 Equine fecal pH measurement methods and storage protocols

The pH of the equine gastrointestinal lumen influences digestion, the microbiome, and enterocyte physiology, each having important impacts on horses. Fecal pH is a simple and noninvasive variable that reflects changes in hindgut pH. The objectives were to evaluate whether there is agreement between fecal pH measured by a meter and pH strips and to determine the effect of storage temperature and time on pH. Fecal samples were collected from 5 broodmares and 8 yearlings on one farm and 12 school horses on another. Feces were collected within 1 min of defecation from an uncontaminated region. A portable pH meter (Hanna Instruments model #9812) and 3 pH strips were used to measure the pH of 4 sub-samples: fresh, 24 h refrigerated at 4°C, 6- and 16-weeks frozen at −20°C. Samples were thawed in a water bath to 20–23°C before measurement. Fecal liquid without the addition of distilled water was used for meter readings. The ranges of the 3 pH strips were 4.5–10 (S1), 5.1–7.2 (S2), and 6.0–7.7 (S3). A 1:2 ratio of feces to distilled water was used for pH strip measurements to ensure readability related to color staining. All pH strips had a strong positive correlation (>0.8) with pH meter. Linear regressions between pH measured by strips and meter resulted in r2 between 0.76 (S1) and 0.86 (S2). Bland-Altman plots quantified agreement between pH meter and S1 (bias 0.005, 95% CI −0.448 to 0.458), S2 (bias −0.033, 95% CI −0.408 to 0.342), and S3(bias −0.044, 95% CI −0.426 to 0.338). Therefore, S2 best reflects the meter pH, with the highest r2 and the narrowest Bland-Altman CI. The influence of storage temperature and time were analyzed with a mixed ANOVA. Significance was set at P < 0.05 and data are presented as means ± sem. The pH of fresh and 6-weeks frozen samples was higher than 24 h refrigerated samples (6.49 ± 0.31, 6.47 ± 0.31, 6.39 ± 0.31, P < 0.001, respectively). No difference was detected comparing the pH of 16-week frozen (6.43 ± 0.31) to other sub-samples. There was a trend for it to be lower than fresh (P = 0.082). This may indicate relevant change due to long-term frozen storage. A difference in the fresh fecal pH (P < 0.001) was detected using all techniques between the 2 farms (pH meter results: 6.78 ± 0.11, 6.20 ± 0.09; respectively). The reason for the difference is beyond the scope of this study. The ability to detect pH differences could be valuable to those interested in management strategies influencing gastrointestinal health. The results of this study indicate that pH strips differ in their ability to reflect pH meter readings, storage temperature and time of storage may influence pH, and pH strips may be useful in detecting relevant differences in fecal pH.

Storage Temperature Effects on the Quality of Chicken Breast and Beef Sirloin

The 7-day storage effects on the quality of chicken breast meat and sirloin beef were evaluated at -2°C, -5°C and -18°C. Drip loss increased, and a sensory score showed lower quality as storage time increased. Storage at -2°C resulted in less drip loss and superior sensory scores for both chicken and sirloin beef compared to meat stored at -5°C and -18°C. The -2°C stored beef also retained redness better than beef stored at the two lower temperatures. Cooking loss for meat cooked in a traditional oven, simmered, or cooked in a convection oven was significantly lower for chicken and beef previously stored at -2°C compared to the meat stored at 5°C or -18°C. The total aerobic bacteria growth did not exceed 1 log/g for beef or 2 log/g for chicken during the 7-day storage period when held at any of the storage temperatures. Thus, short term storage at -2°C was superior to lower frozen temperatures to retain quality without risk of microbiological spoilage.

Survival of Inoculated Vibrio spp., Shigatoxigenic Escherichia coli, Listeria monocytogenes, and Salmonella spp. on Seaweed (Sugar Kelp) During Storage

Bacteria including Vibrio spp. persist in coastal waters and can contaminate edible seaweeds. Pathogens such as Listeria monocytogenes, shigatoxigenic Escherichia coli (STEC), and Salmonella have been associated with and present serious health risks in minimally processed vegetables including seaweeds. This study evaluated the survival of four pathogens inoculated onto two product forms of sugar kelp subjected to different storage temperatures. The inoculation comprised of a cocktail of two Listeria monocytogenes and STEC strains, two Salmonella serovars, and two Vibrio species. STEC and Vibrio were grown and applied in salt-containing media to simulate preharvest contamination, whereas L. monocytogenes and Salmonella inocula were prepared to simulate postharvest contamination. Samples were stored at 4°C and 10°C for 7 days, and 22°C for 8 h. Microbiological analyses were performed periodically (1, 4, 8, 24 h, etc.) to evaluate the effects of storage temperature on pathogen survival. Pathogen populations decreased under all storage conditions, but survival was greatest for all species at 22°C, with STEC exhibiting significantly less reduction (1.8 log CFU/g) than Salmonella, L. monocytogenes, and Vibrio (3.1, 2.7, and 2.7 log CFU/g, respectively) after storage. The largest population reduction (5.3 log CFU/g) was observed in Vibrio stored at 4°C for 7 days. Regardless of storage temperature, all pathogens remained detectable at the end of the study duration. Results emphasize the need for strict adherence to temperature control for kelp as temperature abuse may support pathogen survival, especially STEC, during storage, and the need for prevention of postharvest contamination, particularly with Salmonella.