The present trial verified the effects of spraying microbial agents on odor reduction in commercial pig farms of different operating sizes and barn types. Farms without microbial agent spraying and those sprayed with microbial agents at two different intervals were compared. The treatments included spraying of water alone every day or a mixture of water plus microbial agent at 24 and 72 h intervals. The experimental farms were divided according to size into 1,000-, 3,000-, and 5,000-head farms and according to barn type into gestation, farrowing, nursery, and grower-finisher farms. To compare odor concentration within each housing barn, ammonia and hydrogen sulfide gas levels were measured. The average concentrations of ammonia (p<0.01) and hydrogen sulfide (p<0.05) gas were the lowest in all types of farms sprayed with the microbial agent at a 24 h interval. In farms sprayed with the microbial agent at a 24 h interval, the decrease in ammonia concentration according to barn type was in the following order: farrowing (p<0.01) (11.0 to 1.8 ppm), nursery (p<0.05) (17.0 to 9.2 ppm), grower-finisher (15.3 to 8.8 ppm), and gestation (9.7 to 6.4 ppm) farms. Moreover, spraying the microbial agent at a 24 h interval significantly (p<0.01) decreased ammonia concentration from 19.9 to 10.4 ppm, from 11.1 to 4.1 ppm, and from 8.8 to 5.1 ppm in 5,000-, 3,000-, and 1,000-head farms, respectively. Overall, spraying microbial agents every day may be the most effective method to reduce odor in commercial pig farms.

This study was conducted to develop an agent-based computing platform enabling simulation of on-farm produce contamination by enteric foodborne pathogens, which is herein called PPMCS (Preharvest Produce Microbial Contamination Simulator). Also, fecal contamination of preharvest produce was simulated using PPMCS. Although Agent-based Modeling and Simulation, the tool applied in this study, is rather popular in where socio-economical human behaviors or ecological fate of animals in their niche are to be predicted, the incidence of on-farm produce contamination which are thought to be sporadic has never been simulated using this tool. The agents in PPMCS including crop, animal as a source of fecal contamination, and fly as a vector spreading the fecal contamination are given their intrinsic behaviors that are set to be executed at certain probability. Once all these agents are on-set following the intrinsic behavioral rules, consequences as the sum of all the behaviors in the system can be monitored real-time. When fecal contamination of preharvest produce was simulated in PPMCS as numbers of animals, flies, and initially contaminated plants change, the number of animals intruding cropping area affected most on the number of contaminated plants at harvest. For further application, the behaviors and variables of the agents are adjustable depending on user’s own scenario of interest. This feature allows PPMCS to be utilized in where different simulating conditions are tested.

Bacillus thuringiensis (Bt) is a Gram-positive and soil-dwelling bacterium and well known for its ability to produce insecticidal parasporal crystalline protein inclusions, which have attracted worldwide interest for effective pest management. A diseased silkworm by Bt was first discovered by Japanese scientist Ishiwata Shigetane in 1901, and in 10 years, it was re-discovered in Germany by Ernst Berliner, who isolated it as the cause of a disease called Schlaffsucht in flour moth caterpillars. The first commercial product, Bt. kurstaki HD-1 was released to a market in France in 1938. Optimization of mass production for crystal production and cost down enabled the industrialization to be successful, and now many products, such as WP, EC, SC and tablets are used worldwide. In 1976 Robert A. Zakharyan found that plasmids in Bt are involved in the production of crystal proteins and endospores. Pore formation model and signal transduction model were revealed to explain the mode of action of Bt. Works on Bt resistance included a group of receptors of crystal proteins, such as cadherin, APN and ALP. In 1996, a Bt cry gene was integrated to cotton, which successfully reached markets. AtMT technology was used to generate Bt crops. Now the area planted worldwide to genetically engineered Bt crops increased to 66 million hectares. Refuge may be particularly important in slowing the spread of insects resistant to the Bt insecticides. Researchers are trying to increase the insecticidal efficacy of integrated Bt crystal proteins using recent biotechnology.

The aim of the present study was to determine the effects of soil microbial agent with red ginseng marc on growth of watermelon during 5 months. The three treatments were distributed in a completely randomized design with four replicates per plot. After 1 week in planting dates, the growth of watermelon (full length, stem thichness, leaf length and lead width) showed no significant difference in all treatments. During elongation stage (20 days), soil microbial agent with red ginseng marc was increased by 5% in leaf thickness (May 23) and 7~14% in leaf length (May 16 and 23) when compared to other treatments. For changes in fruit bearing thickness, there were no differences among treatments. Characteristics of watermelon in harvest season have an effect on harvest and length, stalk length, naval length, weight, sugar content and yield, except for harvest and width. In particular, yields increased with treatments with two soil microbial agent (7~12%), indicating that soil microbial agent with red ginseng marc showed higher yield than the other treatments. In conclusion, red ginseng marc-treated soil microbial agents have a positive effect on the harvest season of watermelon and can provide useful information for the selection of the functional microbial properties and the registration of microbial fertilizer.

The aim of this research is to enhance the bottom environment of Geoje fish farm that has been severely contaminated. Treatment of microbial agent and/or calcium oxide significantly changed that environment: in ignition loss, either treatment (25% or 21%)showed better than mixed treatment (13.2%). In COD, the oxygen releasing agent or mixed treatment reduced the index by more than 20%. In T-P and T-N, the effects of CaO2 on them were overwhelming (50% or more) meanwhile that of the microbial agent on them was less than 20%. Also, CaO2 influenced on the microbial flora: Desulfobvibrio thermophilus, a sulfate reducing bacterium decreased in number, considering the increase of pH and rise of redox potential. In contrast, Pseudomonas sp., Pseudoalteromonas sp., Pseudomonas aeruginosa were remarkably dominant over other species with mixed treatment as a PCA analysis confirmed it.

To investigate the effect of several bactericides and fungicides against fruit & vegetable decay grapefruit seed extract(GFSE) was tested in a dilution solution. GFSE was shown to be effective against decay and rind breakdown and to extend the shelf-life of fruits and vegetables during storage and tiansport. Antimicrobial efficiency of GFSE on a wide spectra of gram + & - bacteria, moulds and yeasts was demonstrated by the measurement of minimal inhibitory concentrations performed (Bacteria 10-500ppm, Fungi:250-1,000ppm, Yeasts:100-250ppm). GFSE was separated and extracted into water-soluble fraction, water-insoluble and non-dialyzed fraction to isolate the antimicrobial substances. The water-soluble fraction showed the most active antimicrobial effect. The antimicrobial substances were isolated by gas chromatography. As the result of the isolation using GC, Peak-D was found to be the antimicrobial compound in GFSE. The identification of the most antimicrobial substance was carried out by using GC-MS.