• Food Science and Preservation
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• v.9 no.1
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• pp.19-27
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• 2002

The effect of gamma irradiation was investigated on the microbiological and physicochemical qualities of boiled-dried anchovies (large- and smallsized) packed in PVC film (0.06 ㎜) during storage at 15$\pm$1$\^{C}$ for 6 months. On the other hand, thermoluminescence characteristics of minerals extracted from the sample were analyzed to evaluate its possibility in detecting the irradiated anchovies. The samples were contaminated by microbial levels of 104∼106 CFU/g in total aerobic bacterial counts and negative in coliforms, which were different depending on the sample sizes. Gamma irradiation at 3 kGy was effective for improving the hygienic quality of both samples for 6 months, keeping the microbial population less than 20 CFU/g. Besides it was not detrimental to the quality attributes, such as instrumental color parameters L, a, b, ΔE), browning, TBA value, volatile basic nitrogen, trimethylamine-N and sensory properties(appearance, color, odor, tape, overall acceptability). However, storage conditions (time, temperature, packing) showed a critical factor nfluencing the quality changes of dried anchovies. Thermoluminscence analysis was prove to distinguish irradiated from non-irradiated anchovies by comparing both temperature at which glow curves appear and the curve intensity, that was possible even after 6 months at - 20$\^{C}$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.15 no.3
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• pp.213-221
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• 1986

Japanese spotted mackerels(Scomber tapeinoephalus) were stored at $0^{\circ}C$ for 7days as the maximum, and then, they were stored again at $-3.5^{\circ}C$(partial freezing) or $-20^{\circ}C$(freezing), respectively. During storage by partial freezing, the fishes with a longer period of prestorage at $0^{\circ}C$ showed an earlier increase in the number of bacterial cells on their skin, however, it was not apparent in the freezing storage. K value of the fishes with 7 days of prestorage increased from 20% to 65.4% for 36 days of partial freezing storage, that of the fishes prestored for 0 and 4 days were 39.9% and 53.2% respectively. On contrastly, no drastic increase in K value was observed in the fishes of freezing storage. Content of volatile nitrogen of the fish muscle prestored for 4 days gradually increased from 10mg% to 29.4mg% and 17.2mg% during 36 days of partial freezing and 83 days of freezing storage respectively, that of the fishes with 7 days of prestorage showed no significant increase, moreover, it was decreased within early period of both of the storages. Free drip from the fishes with partial fleering was higher almost 5 times than that from the fishes with freezing, the highest free drip was observed from the fishes with 4 days of prestorage.

• Journal of Animal Science and Technology
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• v.60 no.11
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• pp.27.1-27.8
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• 2018

Background: Enteric methane ($CH_4$) accounts for about 70% of total $CH_4$ emissions from the ruminant animals. Researchers are exploring ways to mitigate enteric $CH_4$ emissions from ruminants. Recently, nano zinc oxide (nZnO) has shown potential in reducing $CH_4$ and hydrogen sulfide ($H_2S$) production from the liquid manure under anaerobic storage conditions. Four different levels of nZnO and two types of feed were mixed with rumen fluid to investigate the efficacy of nZnO in mitigating gaseous production. Methods: All experiments with four replicates were conducted in batches in 250 mL glass bottles paired with the ANKOM$^{RF}$ wireless gas production monitoring system. Gas production was monitored continuously for 72 h at a constant temperature of $39{\pm}1^{\circ}C$ in a water bath. Headspace gas samples were collected using gas-tight syringes from the Tedlar bags connected to the glass bottles and analyzed for greenhouse gases ($CH_4$ and carbon dioxide-$CO_2$) and $H_2S$ concentrations. $CH_4$ and $CO_2$ gas concentrations were analyzed using an SRI-8610 Gas Chromatograph and $H_2S$ concentrations were measured using a Jerome 631X meter. At the same time, substrate (i.e. mixed rumen fluid+ NP treatment+ feed composite) samples were collected from the glass bottles at the beginning and at the end of an experiment for bacterial counts, and volatile fatty acids (VFAs) analysis. Results: Compared to the control treatment the $H_2S$ and GHGs concentration reduction after 72 h of the tested nZnO levels varied between 4.89 to 53.65%. Additionally, 0.47 to 22.21% microbial population reduction was observed from the applied nZnO treatments. Application of nZnO at a rate of $1000{\mu}g\;g^{-1}$ have exhibited the highest amount of concentration reductions for all three gases and microbial population. Conclusion: Results suggest that both 500 and $1000{\mu}g\;g^{-1}$ nZnO application levels have the potential to reduce GHG and $H_2S$ concentrations.

• Korean Journal of Food Science and Technology
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• v.4 no.2
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• pp.100-105
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• 1972

This experiment was conducted to investigate the combined effects of radiation and antiseptics on the keeping qualities of pork sausage, which was treated with potassium sorbate and AF-2(2-(-2-furyl)-3-(5-nitro-2-furyl)-acrylamide), and then followed by gamma radiation of 0.25, 0.5, and 0.75 Mrad. Amounts of treated antiseptics were a quarter, half, and full levels of their maximum permissible concentration. Irradiated and unirradiated sausages were stored for 50 days at $5^{\circ}C\;and\;25^{\circ}C$, and their changes in rancidity, volatile basic nitrogen, bacterial counts, pH, and sensory analysis were examined during the storage period. The results obtained are as follows: 1) Preservative effects of antiseptics were manifested at cold storage; antiseptics treatment of a quarter-level and unirradiation following low-temperature storage showed the same good keeping qualities as the combined treatment of full-level antiseptics and radiation of 0.25 Mrad following high-temperature storage. 2) There did not appear to recognize irradiation-odor, while color and odor were deteriorated intensively by storage temperature. Sausage irradiated with 0.75 Mrad has shown slightly noticeable off-odor at the end of storage at $25^{\circ}C$. 3) The most suitable radiation dose was considered to be 0.5 Mrad, which could extend the storage life about $2{\sim}3$ times longer than untreated.

• Food Science of Animal Resources
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• v.30 no.2
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• pp.313-320
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• 2010

The purpose of this study was to evaluate the freshness of chicken meat during 19 d of storage at $4^{\circ}C$ using a portable electronic nose. The portable system consisted of six different metal oxide sensors and a moisture sensor. Determination of volatile compounds with gas chromatography-mass spectrometry, total bacterial count (TBC), and 2-thiobarbituric acid reactive substances (TBARS) monitored the quality change of the samples. These results were compared with the results measured by the electronic nose system. TBC and TBARS measurements could be separated into five groups and seven groups, respectively, among ten groups. According to principal component analysis and linear discriminant analysis with the signals of the portable electronic nose, the sample groups could be clearly separated into eight groups and nine groups, respectively, among ten groups. The portable electronic nose demonstrated potential for evaluating freshness of stored chicken.

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.10-15
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• 2006

Quality changes of first grade Hanwoo beef were compared with those of third grade Hanwoo beef to investigate effect of initial raw meat quality on maintenance of meat quality during storage for 28 days at $1\;{\pm}\;1^{\circ}C$. Crude fat content of first grade meat was higher, whereas water content was lower, than those of third grade meat. Total bacterial counts of first and third grade beef packaged with polyethylene for 21 days storage at $1\;{\pm}\;1^{\circ}C$ were 106 and $108\;CFU/cm^2$, respectively. Volatile basic nitrogen (VBN) value of first grade meats was lower than that of third grade meat during storage for 28 days at $1\;{\pm}\;1^{\circ}C$. Drip loss percents of first and third grade meats were 4.19 and 6.06% during 14 days storage at $1^{\circ}C$, respectively. L, a, and b values decreased gradually during storage regardless of meat grade, with a value of first grade meat being higher than that of third grade meat at early stage of storage at $1^{\circ}C$.

• Journal of Environmental Health Sciences
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• v.47 no.6
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• pp.540-547
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• 2021

Background: Indoor air pollutants are caused by a number of factors, such as coming in from the outside or being generated by internal activities. Typical indoor air pollutants include nitrogen dioxide and carbon monoxide from household items such as heating appliances and volatile organic compounds from building materials. In addition there is carbon dioxide from human breathing and bacteria from speaking, coughing, and sneezing. Objectives: According to recent research results, most indoor air pollution is known to be greatly affected by internal factors such as burning (biomass for cooking) and various pollutants. These pollutants can have a fatal effect on the human body due to a lack of ventilation facilities. Methods: We fabricated a polydopamine (PDA) layer with Ti substrates as a coating on supported glass fiber fabric to enhance its photo-activity. The PDA layer with TiO₂ was covalently attached to glass fiber fabric using the drop-casting method. The roughness and functional groups of the surface of the Ti substrate/PDA coated glass fiber fabric were verified through infrared imaging microscopy and field emission scanning electron microscopy (FE-SEM). The obtained hybrid Ti substrate/PDA coated glass fiber fabric was investigated for photocatalytic activity by the removal of ammonia and an epidermal Staphylococcus aureus reduction test with lamp (250 nm, 405 nm wavelength) at 24℃. Results: Antibacterial properties were found to reduce epidermal staphylococcus aureus in the Ti substrate/PDA coated glass fiber fabric under 405 nm after three hours. In addition, the Ti substrate/PDA coated glass fiber fabric of VOC reduction rate for ammonia was 50% under 405 nm after 30 min. Conclusions: An electron-hole pair due to photoexcitation is generated in the PDA layer and transferred to the conduction band of TiO₂. This generates a superoxide radical that degrades ammonia and removes epidermal Staphylococcus aureus.

• Journal of Animal Science and Technology
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• v.65 no.1
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• pp.132-148
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• 2023

Ruminants are the main contributors to methane (CH₄), a greenhouse gas emitted by livestock, which leads to global warming. In addition, animals experience heat stress (HS) when exposed to high ambient temperatures. Organic trace minerals are commonly used to prevent the adverse effects of HS in ruminants; however, little is known about the role of these minerals in reducing enteric methane emissions. Hence, this study aimed to investigate the influence of dietary organic trace minerals on rumen fermentation characteristics, enteric methane emissions, and the composition of rumen bacteria and methanogens in heat-stressed dairy steers. Holstein (n=3) and Jersey (n=3) steers were kept separately within a 3×3 Latin square design, and the animals were exposed to HS conditions (Temperature-Humidity Index [THI], 82.79 ± 1.10). For each experiment, the treatments included a Control (Con) consisting of only basal total mixed rations (TMR), National Research Council (NRC) recommended mineral supplementation group (NM; TMR + [Se 0.1 ppm + Zn 30 ppm + Cu 10 ppm]/kg dry matter), and higher concentration of mineral supplementation group (HM; basal TMR + [Se 3.5 ppm + Zn 350 ppm + Cu 28 ppm]/kg dry matter). Higher concentrations of trace mineral supplementation had no influence on methane emissions and rumen bacterial and methanogen communities regardless of breed (p > 0.05). Holstein steers had higher ruminal pH and lower total volatile fatty acid (VFA) concentrations than Jersey steers (p < 0.05). Methane production (g/d) and yield (g/kg dry matter intake) were higher in Jersey steers than in Holstein steers (p < 0.05). The relative abundances of Methanosarcina and Methanobrevibacter olleyae were significantly higher in Holstein steers than in Jersey steers (p < 0.05). Overall, dietary organic trace minerals have no influence on enteric methane emissions in heat-stressed dairy steers; however, breed can influence it through selective alteration of the rumen methanogen community.

• Animal Bioscience
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• v.36 no.5
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• pp.720-730
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• 2023

Objective: This study investigated the effects of corn silage as a source of microbial inoculant containing antifungal and carboxylesterase-producing bacteria on fermentation, aerobic stability, and nutrient digestibility of fermented total mixed ration (FTMR) with different energy levels. Methods: Corn silage was used as a bacterial source by ensiling for 72 d with an inoculant mixture of Lactobacillus brevis 5M2 and L. buchneri 6M1 at a 1:1 ratio. The corn silage without or with inoculant (CON vs MIX) was mixed with the other ingredients to formulate for low and high energy diets (LOW vs HIGH) for Hanwoo steers. All diets were ensiled into 20 L mini silo (5 kg) for 40 d in quadruplicate. Results: The MIX diets had lower (p<0.05) acid detergent fiber with higher (p<0.05) in vitro digestibilities of dry matter and neutral detergent fiber compared to the CON diets. In terms of fermentation characteristics, the MIX diets had higher (p<0.05) acetate than the CON diets. The MIX diets had extended (p<0.05) lactic acid bacteria growth at 4 to 7 d of aerobic exposure and showed lower (p<0.05) yeast growth at 7 d of aerobic exposure than the CON diets. In terms of rumen fermentation, the MIX diets had higher (p<0.05) total fermentable fraction and total volatile fatty acid, with lower (p<0.05) pH than those of CON diets. The interaction (p = 0.036) between inoculant and diet level was only found in the immediately fermentable fraction, which inoculant was only effective on LOW diets. Conclusion: Application of corn silage with inoculant on FTMR presented an antifungal effect by inhibiting yeast at aerobic exposure and a carboxylesterase effect by improving nutrient digestibility. It also indicated that fermented feedstuffs could be used as microbial source for FTMR. Generally, the interaction between inoculant and diet level had less effect on this FTMR study.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.219-226
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• 1985

To investigate potential application of radurization technique as an effective tool for controlling histamine accumulation, histamine contents were determined in fresh Korean mackerel meat samples irradiated at six dose levels of gamma radiation up to 1 Mrad during 35 day-storage at $0^{\circ},\;5^{\circ}\;and\;10^{\circ}C$. Total bacterial counts, total volatile bases and trimethylamine contents were also estimated. The minimum and maximum doses for Korean mackerel were determined to be 0.2 and 0.5 Mrad, respectively. Irradiation induced redening of fish muscle tissue and redening appeared to be dose dependent. At low doses, this redening contributed positively to the overall sensory qualities. At 0.5 and 1.0 Mrad, on the other hand, meat samples were excessively redened to the extent that red and white muscle layers were not readily distinguishable. No appreciable histamine accumulation occured during entire 35 day-storage in fresh mackerel meats, whether irradiated or not, when they were kept at ice temperature. At $5^{\circ}C$, histamine started to accumulate slightly during late storage in the samples irradiated at low doses. Even in the unirradiated samples, the histamine accumulation did not exceed the level of 10.0 mg per 100g meat until the 28th day at $5^{\circ}C$. At $10^{\circ}C$, however, histamine accumulation in the unirradiated was phenomenal from very early storage and the values reached 827.5 mg per 100g meat by the 35th day, while histamine accumulation in the irradiated was severely suppressed. Irradiation invariably brought about a significant reduction of initial microflora, disrupting normal spoilage pattern. This was reflected in the suppression of not only histamine but also total volatile bases and trimethylamine accumulation during post-irradiation storage at refrigerated temperatures.