Hyperspectral fluorescence imaging techniques were investigated for detection of two genera of microbial biofilms on stainless steel material which is commonly used to manufacture food processing equipment. Stainless steel coupons were deposited in nonpathogenic E. coli O157:H7 and Salmonella cultures, prepared using M9 minimal medium with casamino acids (M9C), for 6 days at 37°C. Hyperspectral fluorescence emission images of the biofilm formations on the stainless coupons were acquired from 416 to 700 nm with the use of ultraviolet-A (320-400 nm) excitation. In general, emission peaks for both bacteria were observed in the blue region at approximately 480 nm and thus provided the highest contrast between the biofilms and background stainless steel coupons. A simple thresholding of the 480 nm image showed significantly larger biofilm regions for E. coli O157:H7 than for Salmonella. Viable cell counts suggested that Salmonella formed significantly higher density biofilm regions than E. coli O157:H7 in M9C medium. On the basis of principal component analysis (PCA) of the hyperspectral fluorescence images, the second principal component image exhibited the most distinguishable morphological differences for the concentrated biofilm formations between E. coli and Salmonella. E. coli formed granular aggregates of biofilms above the medium on stainless steel while Salmonella formed dense biofilm in the medium-air interface region (pellicle). This investigation demonstrated the feasibility of implementing fluorescence imaging techniques to rapidly screen large surface areas of food processing equipment for bacterial contamination.

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The amount of salt intake of Korean people is 11.4 grams per a day, which is 2.3 times of the recommended daily salt intake by WHO-5 grams of salt a day. The relationship between high salt consumption and increased risk of high blood pressure, observed not only in hypertensive but also in normotensive patients. High salt intake is also associated with an increased risk of heart attack, cerebral ischemia and osteoporosis. Therefore, this research is for developing a salt taste sensor to reduce sodium consumption and improve meal habits for the perception of a more bland taste of most foods. When the sensor was put into food sample, current intensity achieved with distribution cables. Current intensity was correlate with a simple equivalent of salt taste stimulus intensity. The salt taste sensor consists of salinity & temperature measuring probe, signal processing circuit and LCD display & LED warning light. When salinity is going over a set point, LCD displayer indicate salt taste on LCD panel by percent value (%), and at the same time, blue LED light change to red LED light. So we could know the grade of salt taste in soup before meals conveniently and objectively. The results show that operating range of 10 to 80℃ and accuracy of ±0.1% were achieved with an analysis time of about 2 or 3 sec. Moderate reductions in salt intake can help to avert adult diseases and lead a healthy life.