Qualitative and quantitative analysis of organochlorine insecticide residues were conducted in water, sediment, aquatic plants and animals from 3 freshwater reservoirs. Ninety water samples, 90 sediment samples, 397 aquatic plants samples and 121 aquatic animals samples were collected during March-April and August-September 1989. There were about 14 kinds of aquatic plants, such as water hyacinth, water lettuce, algae and water lilly etc. Aquatic animals are fish, shrimps and snails, but most of them are fish. They are striped snake-head fish, carp and catfish etc. Total samples of 698 were analyzed by using gas chromatographic techniques at Agricultural Toxic Substances Division. The results indicated that 5 kinds of insecticides were found in most samples. They were lindane, heptachlor, aldrin, dieldrin, DDT and derivatives. Dieldrin was detected at higher concentration and found in all samples. The residue level of dieldrin ranged from 0.01-0.12 ppb in water, 0.005-0.036 ppm in sediment, 0.001-0.138 ppm in aquatic plants and 0.001-0.037 ppm in aquatic animals respectively. The accumulation of dieldrin residue in water and aquatic plant samples from all reservoirs are not different but the level of dieldrin residue in sediment samples from Bueng Boraphed is higher than the other 2 reservoris. However the levels of dieldrin residue in sediment, aquatic plant and aquatic animal samples higher than those in water samples respectively.

The production of protein hydrolysate from shrimp cooking water using enzyme Neutrase 0.5L was studied. Variations of enzymatic hydrolysis conditions consisted of enzyme concentration at 0, 0.5, 1.0, 1.5 and 2.0 % V/V; pH 5.5, 6.5 and 7.5; temperature 50, 55 and 60 deg C; and the hydrolysing time; 15, 30, 45, 60, 75 and 90 minute. The optimum condition for production of hydrolysate which gave the maximum amino acid nitrogen at 3.50 mg N/ml were 0.5 % Neutrase, pH 6.5, 50 deg C and 30 minute. The hydrolysate was dried by freeze-drying. The dried product had dark brown color with considerable shrimp flavor and absorbed moisture quite readily. The product contained 3.80 % moisture, 51.89 % protein, 6.57 % fat, 24.76 % ash and 12.99 % carbohydrate. Sensory evaluation on the color and shrimp odor of dried product comparing to the freeze dried unhydrolysed cooking water product showed that the freeze-dried hydrolysate obtained higher scores in color and odor. However, sensory evaluation of the products after dissolving in water revealed that neither the hydrolysated nor unhydrolysed products had the significant differences in color, shrimp odor, sweet taste, bitter taste and overall flavor.

Water hyacinth, water lettuce, mungbean pericarp, banana pseudostems and kapok waste (control) were used as food supplement to straw mushroom culture. The yields of all treatments were not significantly different from the control, which ranged from 327.50-419.75 grams fresh weight per bed. Number of fruiting bodies per bed ranged from 56.00-73.75. Average fresh weight of fruiting bodies was 5.84-8.30 grams and size of fruiting body was 24.8-27.1x21.4-25.1 mm.

Production of protein hydrolysate from shrimp precooking water using enzyme Nutrase 0.5 L was studied. Variations in the enzymatic hydrolysis were composed of the quantity of enzyme (0, 0.5, 1.0, 1.5 and 2.0 percent v/v), the pH (5.5, 6.5 and 7.5), the hydrolysing temperature (50, 55 and 60 deg C) and the hydrolysing time (15, 30, 45, 60, 75 and 90 min). The optimum condition for production of hydrolysate which gave the maximum amino acid nitrogen at 3.50 mgN/ml was 0.5 percent Nutrase, pH 6.5 50 deg C and 10 min. The chemical composition of the hydrolysate produced was 94.51 percent moisture, 2.52 percent protein, 0.33 percent fat, 1.77 percent ash and 0.88 percent carbohydrate. The hydrolysate was then freeze-dried. The dried product absorbed moisture quite easily and contained 3.80 percent moisture, 51.89 percent protein, 6.57 percent fat, 24.76 percent ash and 12.99 percent carbohydrate. To improve the quality of the dried product, the hydrolysate was mixed with 20 percent maltodextrin solution until the mixture had 10 percent total soluble solid before freeze-drying. It was found that the dried product absorbed moisture less rapidly and was ground easily. The composition of the improved product was 5.23 percent moisture, 36.98 percent protein, 3.71 percent fat, 16.61 percent ash and 41.98 percent carbohydrate. Sensory evaluation on the color and shrimp odor of these two dries products comparing to the freezed-dried unhydrolysed precooking water products showed that the freezed-dried hydrolysate without maltodextrin solution obtained the highest scores in color and odor. However, sensory evaluation the products after dissolving in water revealed that neither the hydrolysed nor unhydrolysed products had the significant differences in color, shrimp for, sweet taste, bitter taste and overall flavor.

Selective medium for investigation of C. perfringens in food, water and beverage was developed to substitute for FM-CW Agar due to no production of this medium in Japan. Five formulas of media: Clostridium welchii Brain Heart Infusion Agar (CWB), Clostridium welchii Agar (CWA), Loctose Egg-Yolk Agar (LEY), Liver Veal Agar (LV) and Modified Brain Heart Infusion Agar (Mod.BHI), were selected in this research. The quality and efficiency of these media was compared to FM-CW by using the reference standard culture of C. perfringens. The results showed that Mod.BHI is the most effective medium for observing the appearance of colony, the lecithinase reaction in egg yolk and Nagler reaction of organism. Therefore it was found that the Mod.BHI must be adjusted pH to 7.6 and boiled for sterilization then neomycin 400/ug/m/ was added. The developed medium and FM-CW were used to investigate C. perfringens, isolated from 35 samples of food, water and beverage and C. bifermentans isolated from 5 samples of food. The result showed that the developed medium, Mod. BHI, can be used to investigate C. perfringens in stead of FM-CW Agar.

Anthracnose pathogen on mango fruit cv. Nam Dok Mai and Mahajanaka were isolated and screened for a virulent isolate. Among 6 isolates, Colletotrichum gloeosporioides Ml1 showed the strongest pathogenic activity. The isolate was dual cultured with 11 isolates of microorganisms isolated from fermented pork sausage (CM-NM-1 CM-NM-2, CM-NM-3), preserved fish (CM-PF-1, CM-PF-2), natto (CM-TN), yoghurt (CM-YK), vinegar (SK-AV), nata decoco (CM-NA), ragi (CM-LP) and a laboratory contaminant (CON-1) for antagonistic detection. The results came out that CM-NM-3, CON-1, CM-NA and CM-LP exhibited greater inhibition percentages i.e., 66.82, 62.98, 37.02 and 34.18 percent, respectively. All 11 isolates were further tested for the prevention of C. gloeosporioides Ml1 infection on postharvest mango fruit. It was found that the fruit dipped in the cell suspension of CM-NA, CM-YK and CM-PF-2 after the inoculation had small lesion size which differed from the control group (not dipped), The efficacy of combined treatments using CM-NA in combination with 50 or 54 deg C hot water for 5 minutes were investigated on wounded mango fruit. The least size was found on the fruit treated with 54 deg C for 5 minutes either with or without dipping in the antagonistic cell suspension. The fruit dipping in cell suspension of CM-NA in combination with 54 deg C hot water for 5 minutes did not change in pulp color, flesh color, weight loss, texture, total soluble solid, titratable acidify and sensory quality.