• Food Science and Preservation
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• v.14 no.1
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• pp.1-7
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• 2007

This study was conducted to determine if chlorine dioxide ($ClO_{2}$) gas might minimize microbial contamination of fresh produce. After exposing grapes to 20 ppm or 40 ppm of chlorine dioxide gas in a closed container, grapes treated with 20 ppm $ClO_{2}$ were packaged in Ny/PE/L-LDPE pouches, stapes treated with 40 ppm $ClO_{2}$ were placed in an empty corrugated box, and untreated control grapes were placed in a box with a sachet containing $ClO_{2}$ gas adsorbed to silica gel (a silica gel pad). The free volume of the sachet material allowed the release of $ClO_{2}$ gas into the headspace of packages containing fresh grapes. Control fruit not exposed to $ClO_{2}$, was placed in a box and stored at either $25^{\circ}C$ or $0^{\circ}C$. Fruit in Ny/PE/L-LDPE film treated with 20 ppm $ClO_{2}$ lost almost no weight during storage at either $25^{\circ}C$ or $0^{\circ}C$. Such fruit had a lower soluble solid content than did other fruit samples. Titratable acidity tended to fall rapidly during storage at either $25^{\circ}C$ or $0^{\circ}C$. Anthocyanin content of grapes decreased over 21 days at $25^{\circ}C$ but increased over 10 weeks at $0^{\circ}C$. The total microbial count of grapes treated with $ClO_{2}$ gas and silica gel pads were lower than controls at $25^{\circ}C$. Fruit treated with 20 ppm $ClO_{2}$ and packaged in Ny/PE/L-LDPE pouches had lower microbial counts than other fruit samples when stored at $0^{\circ}C$. The silica gel pad did not significantly improve total microbial count (compared to untreated control samples) at $0^{\circ}C$. This result may be attributed to a higher rate of diffusion of $ClO_{2}$ gas at room temperature.

• Food Science and Preservation
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• v.16 no.2
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• pp.276-285
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• 2009

This study evaluated the microbiological quality and safety of food items(seafood, meat, eggs, and frozen food) supplied to elementary school food services, during delivery, and analyzed the distribution/delivery system. To this end, 10 food items supplied by 13 factories in Daegu and Gyeongbuk were chosen for study. Beef and pork were delivered directly to schools in freezer vans. Seafood, chicken, and frozen food were delivered to schools by refrigerated vans(${\leq}10^{\circ}C$) that made other delivery stops before arriving at schools. After food was delivered to schools, total bacterial counts and coliforms(respectively) were as follows: mackerel($2.0{\times}10^2-3.2{\times}10^5$, $<5-4.0{\times}10^3CFU/g$), common squid($2.5{\times}10^4-6.6{\times}10^5$, $1.6{\times}10^2-6.0{\times}10^3CFU/g$), shellfish($3.2{\times}10^5-1.7{\times}10^3$, $4.0{\times}10^3-3.0{\times}10\;CFU/g$), boiled fish paste($1.9{\times}10^4$, <5 CFU/g), beef($9.2{\times}10^2-6.4{\times}10^4$, $<5-2.0{\times}10\;CFU/g$), pork($2.6{\times}10^3-1.3{\times}10^6$, $<5-2.7{\times}10^2CFU/g$), chicken($1.0{\times}10^4$, $2.4{\times}10^2CFU/g$), egg($<5-2.3{\times}10^2$, <5 CFU/g), frozen mandu($3.2{\times}10^3-9.5{\times}10^4$, <5 CFU/g), and frozen noodles($<5-9.0{\times}10$, <5 CFU/g). Bacillus cereus($2.0{\times}10\;CFU/g$) and E. coli($1.0{\times}10\;CFU/g$) were detected on shellfish, and Staphylococcus aureuswas detected on pork($3.1{\times}10\;CFU/g$) and chicken($7.8{\times}10\;CFU/g$). Most food items were double-wrapped in vinyl and placed in corrugated cardboard boxes prior to delivery, and the boxes weremixed with other food items when they were put in the vans. There was no cross-contamination during distribution. However, total shellfish bacterial counts increased slightly. These results indicate that foods need to be completely pasteurized during processing. Frozen food items should not be mixed and should be delivered by freezer vans(${\leq}4^{\circ}C$). The number of stops made during distribution/delivery should be reduced.

• Korean Journal of Agricultural Science
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• v.9 no.1
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• pp.357-370
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• 1982

Recent concern regarding price and availability of fossil fuels has spurred the interest in alternative sources for farm crop drying. Among the available options such as biomass energy, wind power, nuclear energy and solar energy etc., the increasing attention is being directed to the utilization of heat from solar energy especially for farm crop drying. Even though solar energy is dispersed over a large land area and only a relatively small amount of energy can be simply collected, the advantages of solar energy is that the energy is free, non-polluting. The study reported here was designed to help supply the informations for the development of simple and relatively inexpensive solar warehouse for farm crop drying and storage. Specifically, the objectives of this study were to determine the performance of the solar collector fabricated, to compare solar supplemented heat drying with natural air drying and to develop a simulation model of temperature in stored grain, which can be used to study the effects due to changes in ambient air temperature. For those above objectives, solar collector was fabricated from available materials. Corrugated steel galvanized sheet, painted flat black, was used as absorbers and clear 0.2mm polyethylene sheet was the cover material. The warehouse for rough rice drying and storage was constructed with concrete block, and the solar collector was used as the roof of warehouse instead of original roofing system of it. The results obtained in this study were as follows: 1. The thermal efficiency of the solar collector was average 26 percent and the overall heat transfer coefficient of the collector was approximately $25kJ/hr.m^2\;^{\circ}K$. 2. Solar heated air was sufficient to dry one cubic meter of rough rice from 23.5 to 15.0 percent in 7 days and natural air was able to dry the same amount of rough rice from 20.0 to 5 percent in l2 days. 3. Drying with solar heat reduced the required drying time to dry the same amount of rough rice into a half compared to natural air drying, but overdrying problems of the bottom layer were so severe that these problems should be thoroughly analyzed. 4. Simulation model of temperature in stored grain was developed and the results of predicted temperature agreed well with test results. 5. Based on those simulated temperature, changes in the grain-temperature were a large at the points of the wallside and the damage of the grain would be severe at the contact area of wall.

• Korean Journal of Weed Science
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• v.17 no.4
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• pp.368-374
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• 1997

Investigated ware the decomposition of mulch paper, weed occurrence, and rice growth and yield in transplanting rice culture with paper mulching in 1996 and 1997. The mulch paper were developed from domestic old corrugated container. In the experiment of 1996 where 25 percent of nitrogen fertilizer was applied as tillering fertilizer at 15 days after transplanting, it took about 28 to 40 days for the mulch paper to reach 50 percent decomposition according to types of mulch paper and fertilizer amount. The decomposition was faster in 18kg N/10a fertilization plot than in 12kg N/10a fertilization plot, and slower in the mulch paper treated with polyamidepolyamine epichlorohydrin resin(PPE) for the reinforcement of wet strength than in the mulch paper without PPE. In the experiment of 1997 where nitrogen fertilizer was not applied at tillering stage and instead 70 percent of nitrogen fertilizer was supplied as basal fertilizer, it took more than 42 days for the mulch paper(PPF treated) to reach 50 percent decomposition. Paper mulching was found to be very effective in controlling the paddy weeds at early stage of rice growth, but the efficacy, of weed control decreased especially in the mulch paper without PPE at later stage of rite growth due to the occurrence of Ludwigia prostrata in 1996. Few weeds occurred even in non-mulched plot without herbicide in 1997, rending difficulties in evaluating the efficacy of mulch paper in weed control, However, it could be deduced from the durability of mulch paper that paper mulching would have had sufficient efficacy of weed control. Rice yield was only 185kg/10a in the plot without mulching and weed control, but 657kg/10a and 771kg/10a in the paper(PPE treated) mulching plot with 12kgN/10a and 18kgN/10a, respectively, in 1996. The paper mulching plot showed rice yield similar to the weed control plot with herbicide in 1997. It would be concluded that paper mulching could ensure effective weed control and as high yield as the conventional rice cultivation with herbicidal weed control if the corresponding amount of basal nitrogen fertilizer is increased instead of omitting the nitrogen fertilizer at tillering stage.

• Food Science and Preservation
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• v.17 no.5
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• pp.586-594
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• 2010

We evaluated changes in the microbiological quality and safety of food items (vegetables, seaweed, and processed food) supplied to elementary school food services to evaluate the distribution/delivery system. Pretreated vegetables, seaweed, and processed food were delivered to schools in refrigerated (${\leq}10^{\circ}C$) vans that made several delivery stops before arriving at the schools. During the distribution stage, total plate and coliforms counts were: bellflower roots $7.6{\times}10^5-6.7{\times}10^6$ and $5.8{\times}10^4-5.2{\times}10^5$ CFU/g; blanched bracken $4.5{\times}10^3-2.1{\times}10^5$, $5.0{\times}10^3-1{\times}10^4$ CFU/g; onion $1.2{\times}10^4-1.4{\times}10^4$, $5.0{\times}10$ CFU/g; soybean sprouts $9.6{\times}10^4-6.3{\times}10^7$ and $1.1{\times}10^3-1.2{\times}10^7$ CFU/g; soybean curd < $10-9.7{\times}10^5$ and < $10-2.3{\times}10^5$ CFU/g; and starch jelly < $10-3.8{\times}10^3$ and <10 CFU/g. Bacillus cereus < $10-4.1{\times}10^2$ CFU/g, Escherichia coli $1.0{\times}10-2.0{\times}10$ CFU/g, and Staphylococcus aureus $1.3{\times}10^2-4.1{\times}10^2$ CFU/g were detected on peeled bellflower, whereas B. cereus < $10-4.1{\times}10^2$ CFU/g, Listeria monocytogenes $1.0{\times}10-4.5{\times}10^2$ CFU/g, and S. aureus $1.8{\times}10^2-4.5{\times}10^2$ CFU/g, were detected on soybean sprouts. Most food items were double-wrapped in vinyl and placed in corrugated cardboard boxes prior to delivery, but the boxes, when placed in vans, were not segregated from other food items being delivered to schools and other destinations.