Zein, corn prolamine, was dissolved in several organic solvents to make films and their properties were examined. Ethanol with 20% water and acetone with 30% water were found to dissolve zein well and transform it into a transparent flexible film after moderate drying. Both films showed similar breaking strength to that of commercial thin film of polyvinylidene chloride for food use and were digested with proteases. Only the film prepared from acetone solution showed a relatively low water permeability. This water permeation was found to depend strongly on the rate of diffusion. 1,2-Epoxy-3-chloropropane (ECP) was added into the acetone solution to cross-link the zein molecules for the purpose of improving the breaking strength and water-resistant properties of the film. Alpha-chymotrypsin was found to digest the film even after the modification with ECP. However, this cross-linking resulted in little improvement in the water-resistant properties of the film and also reduced its flexibility.

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.

Aeromonas hydrophila, a ubiquitous inhabitant of aquatic environments, commonly expresses several cell-surface properties that may contribute to virulence. Since many aquatic microorganisms in hostile environments can withstand starvation conditions for long periods, we examined the effect of storage under nutrient poor conditions on the expression of cell-surface properties of this pathogen. Phenotypes studied were: (1) cell surface hydrophobicity and charge, and (2) the ability to bind connective-tissue proteins and lactoferrin. Our results suggest that the response of A. hydrophila to nutrient-poor conditions is regimen specific. Generally, A. hydrophila cells became more hydrophobic and significantly increased their ability to bind the iron-binding glycoprotein lactoferrin when the bacterium was stored under nutrient-poor conditions; however, under these conditions, the cells seemed to lose their ability to bind connective tissue proteins.

The viscous and viscoelastic behaviour of food emulsions containing a mixture of egg yolk and sucrose stearate as a function of oil and sucrose stearate concentrations were studied. Oil concentrations ranged between 40- 55% w/w for emulsions containing 5% w/w sucrose stearate and sucrose ester concentrations varied between 0-10% w/w for emulsions containing 50% w/w oil. steady flow, linear oscillatory shear tests and droplet size distribution measurements were carried out. An increase in oil or emulsifier concentration produced an increase in both the steady-state viscosity and in the viscoelastic functions. The results have been explained on the basis of the relationship between the structural parameters and the rheology of the emulsions studied.