Kazuhiko Itoh

Decontamination of lettuce using acidic electrolyzed water.

The disinfectant effect of acidic electrolyzed water (AcEW), ozonated water, and sodium hypochlorite (NaOCl) solution on lettuce was examined. AcEW (pH 2.6; oxidation reduction potential, 1140 mV; 30 ppm of available chlorine) and NaOCl solution (150 ppm of available chlorine) reduced viable aerobes in lettuce by 2 log CFU/g within 10 min. For lettuce washed in alkaline electrolyzed water (AIEW) for 1 min and then disinfected in AcEW for 1 min, viable aerobes were reduced by 2 log CFU/g. On the other hand, ozonated water containing 5 ppm of ozone reduced viable aerobes in lettuce 1.5 log CFU/g within 10 min. It was discovered that AcEW showed a higher disinfectant effect than did ozonated water significantly at P < 0.05. It was confirmed by swabbing test that AcEW, ozonated water, and NaOCI solution removed aerobic bacteria, coliform bacteria, molds, and yeasts on the surface of lettuce. Therefore, residual microorganisms after the decontamination of lettuce were either in the inside of the cellular tissue, such as the stomata, or making biofilm on the surface of lettuce. Biofilms were observed by a scanning electron microscope on the surface of the lettuce treated with AcEW. Moreover, it was shown that the spores of bacteria on the surface were not removed by any treatment in this study. However, it was also observed that the surface structure of lettuce was not damaged by any treatment in this study. Thus, the use of AcEW for decontamination of fresh lettuce was suggested to be an effective means of controlling microorganisms.

Efficacy of Acidic Electrolyzed Water for Microbial Decontamination of Cucumbers and Strawberries

An examination was made of the efficacy of acidic electrolyzed water (AcEW, 30 ppm free available chlorine), ozonated water (5 ppm ozone), and a sodium hypochlorite solution (NaOCl, 150 ppm free available chlorine) for use as potential sanitizers of cucumbers and strawberries. AcEW and NaOCl reduced the aerobic mesophiles naturally present on cucumbers within 10 min by 1.4 and 1.2 log CFU per cucumber, respectively. The reduction by ozonated water (0.7 log CFU per cucumber) was significantly less than that of AcEW or NaOCl (P < or = 0.05). Cucumbers washed in alkaline electrolyzed water for 5 min and then treated with AcEW for 5 min showed a reduction in aerobic mesophiles that was at least 2 log CFU per cucumber greater than that of other treatments (P < or = 0.05). This treatment was also effective in reducing levels of coliform bacteria and fungi associated with cucumbers. All treatments offered greater microbial reduction on the cucumber surface than in the cucumber homogenate. Aerobic mesophiles associated with strawberries were reduced by less than 1 log CFU per strawberry after each treatment. Coliform bacteria and fungi associated with strawberries were reduced by 1.0 to 1.5 log CFU per strawberry after each treatment. Microbial reduction was approximately 0.5 log CFU per strawberry greater on the strawberry surface than in the strawberry homogenate. However, neither treatment was able to completely inactivate or remove the microorganisms from the surface of the cucumber or strawberry.

Influence of inoculation method, spot inoculation site, and inoculation size on the efficacy of acidic electrolyzed water against pathogens on lettuce.

The influence of bacterial inoculation methods on the efficacy of sanitizers against pathogens was examined. Dip and spot inoculation methods were employed in this study to evaluate the effectiveness of acidic electrolyzed water (AcEW) and chlorinated water (200 ppm free available chlorine) against Escherichia coli O157:H7 and Salmonella spp. Ten pieces of lettuce leaf (5 by 5 cm) were inoculated by each method then immersed in 1.5 liters of AcEW, chlorinated water, or sterile distilled water for 1 min with agitation (150 rpm) at room temperature. The outer (abaxial) and inner (adaxial) surfaces of the lettuce leaf were distinguished in the spot inoculation. Initial inoculated pathogen population was in the range 7.3 to 7.8 log CFU/g. Treatment with AcEW and chlorinated water resulted in a 1 log CFU/g or less reduction of E. coli O157:H7 and Salmonella populations inoculated with the dip method. Spot inoculation of the inner surface of the lettuce leaf with AcEW and chlorinated water reduced the number of E. coli O157:H7 and Salmonella by approximately 2.7 and 2.5 log CFU/g, respectively. Spot inoculation of the outer surface of the lettuce leaf with both sanitizers resulted in approximately 4.6 and 4.4 log CFU/g reductions of E. coli O157:H7 and Salmonella, respectively. The influence of inoculation population size was also examined. Each sanitizer could not completely eliminate the pathogens when E. coli O157:H7 and Salmonella cells inoculated on the lettuce were of low population size (10(3) to 10(4) CFU/g), regardless of the inoculation technique.

Efficacy of acidic electrolyzed water ice for pathogen control on lettuce.

Acidic electrolyzed water (AcEW) was used as frozen AcEW (AcEW-ice) for inactivation of Listeria monocytogenes and Escherichia coli O157:H7 on lettuce. AcEW-ice was prepared from AcEW with 20, 50, 100, and 200 ppm of available chlorine by freezing at -40 degrees C and generated 30, 70, 150, and 240 ppm of chlorine gas (Cl2), respectively. The AcEW-ice was placed into styrene-foam containers with lettuce samples at 20 degrees C for 24 h. Although AcEW-ice generating 30 ppm Cl2 had no effect on L. monocytogenes cell counts, AcEW-ice generating 70 to 240 ppm of Cl2 significantly (P < 0.05) reduced L. monocytogenes by ca. 1.5 log CFU/g. E. coli O157:H7 cell counts were reduced by 1.0 log CFU/g with AcEW-ice generating 30 ppm of Cl2. AcEW-ice generating 70 and 150 ppm of Cl2 reduced E. coli O157:H7 by 2.0 log CFU/g. Further significant reduction of E. coli O157:H7 (2.5 log CFU/g) was demonstrated by treatment with AcEW-ice generating 240 ppm of Cl2. However, treatment with AcEW-ice generating 240 ppm of Cl2 resulted in a physiological disorder resembling leaf burn. AcEW-ice that generated less than 150 ppm of Cl2 had no effect on the surface color of the lettuce. AcEW-ice, regardless of the concentration of the emission of Cl2, had no effect on the ascorbic acid content in the lettuce. The weight ratio of lettuce to AcEW-ice required was determined to be over 1:10. The bactericidal effect of AcEW-ice appeared within the first 2 h. The use of AcEW-ice provides simultaneously for low temperature storage and inactivation of bacteria.

Development of an automatic rice-quality inspection system

The need has arisen in rice-drying facilities in Japan for an automatic method to measure quality aspects of rice when it arrives at the drying facility. A near-infrared (NIR) transmission instrument was used to obtain NIR spectra of damp rough rice and damp brown rice. Calibration models were developed from the original spectra and reference analysis data to determine moisture and protein content of the samples. A visible light (VIS) segregator was used to determine sound whole kernel of brown rice. The precision and accuracy of the NIR instrument and the VIS segregator were found to be sufficiently high to determine moisture and protein content, and sound whole kernel ratio. An automatic rice-quality inspection system was consequently developed. The system consisted of a rice huller, a rice cleaner, an NIR instrument and a VIS segregator, and it was controlled by a computer. Based on the rice-quality information, this system enabled rough rice transported to a rice-drying facility to be classified into six qualitative grades.

Decontaminative effect of frozen acidic electrolyzed water on lettuce.

We investigated the effects of frozen acidic electrolyzed water (AcEW) on lettuce during storage in a styrene-foam container. The lettuce was kept at 2 to 3 degrees C for 24 h. Populations of aerobic bacteria associated with lettuce packed in frozen AcEW were reduced by 1.5 log CFU/g after storage for 24 h. With frozen tap water, no microorganism populations tested in this study were reduced. A frozen mixture of AcEW and alkaline electrolyzed water (AlEW) also failed to reduce populations of microorganisms associated with lettuce. Although chlorine gas was produced by frozen AcEW, it was not produced by the AcEW-AlEW mixture. This result indicates that the main factor in the decontaminative effect of frozen AcEW was the production of chlorine gas. Accordingly, low-temperature storage and decontamination could be achieved simultaneously with frozen AcEW during distribution.

Diazepines. III. Synthesis of 4H-Pyrrolo[1,2-a] thieno[3,2-f] [1,4] diazepines†

The synthesis of 4H-pyrrolo[1,2-a]thieno[3,2-f] [1,4]diazepines (8) is described. Phthal-imidomethylfurans 1 were treated with bromine-methanol to give the dihydrofurans 2, which were hydrolyzed and then liydrogenated over Raney nickel or with zinc-acetic acid to afford the 1,4-diketones 5. Condensation of 2-amino-3-benzoylthiophenes 6 with 5 gave 3-benzoyl-2-pyrrolylthiopenes 7. The removal of the phthaloyl group from 7 with hydrazine hydrate and ring closure to the diazepine ring yielded the new heterocycles 8.

On-line Near Infrared Spectroscopic Sensing Technique for Assessing Milk Quality during Milking

There has been a need in recent years for a method that will enable dairy farmers to assess milk quality of individual cows during milking. We constructed on-line near-infrared (NIR) spectroscopic sensing system on an experimental basis. This system enables NIR spectra of unhomogenized milk to be obtained during milking over a wavelength range of 600 nm to 1050 nm. We also developed calibration models for predicting three major milk constituents (fat, protein and lactose), somatic cell count (SCC) and milk urea nitrogen (MUN) of unhomogenized milk, and we validated the precision and accuracy of the models. The coefficient of determination (r2) and standard error of prediction (SEP) of the validation set for fat were 0.95 and 0.42%, respectively. The values of r2 and SEP for protein were 0.91 and 0.09%, respectively; the values of r2 and SEP for lactose were 0.94 and 0.05%, respectively; the values of r2 and SEP for SCC were 0.82 and 0.27 log SCC/mL, respectively; and the values of r2 and SEP for MUN were 0.90 and 1.33 mg/dL, respectively. These results indicated that the NIR sensing system developed in this study could be used to assess milk quality in real time during milking. The system can provide dairy farmers with information on milk quality and physiological condition of individual cows and therefore give them feedback control for optimizing dairy farm management.

Accuracy of Near-infrared Transmission Spectroscopy for Determining Rice Constituent Contents and Improvement in the Accuracy

The accuracy in determination of rice constituent contents using a commercial nearinfrared transmission (NIRT) instrument was validated. And the accuracy of measurements using this instrument was improved by modifying light filters and calibration equations used in the instrument. In the determination of moisture content, the coefficient of determination (r2) was 0.98, standard error of prediction (SEP) was 0.13%, and bias was -0.02%. In the determination of protein content, r2 was 0.90, SEP was 0.17%, and bias was 0.01%. These results show that the newly developed instrument is sufficiently accurate to be used instead of reference analysis for measuring moisture content and protein content of brown rice. An automatic rice-quality inspection system was designed. The system consisted of a rice huller, a rice cleaner, an NIRT instrument and a visible light (VIS) segregator. Based on rice-quality information, this system enables rough rice transported to a rice grain elevator to be classified into six qualitative grades.

Milk-quality monitoring by near-infrared spectroscopy for artificial intelligence in dairy farming

Abstract A near-infrared (NIR) spectroscopic sensing system was constructed on an experimental basis. This system enables NIR spectra of unhomogenized milk to be obtained during milking over a wavelength range of 600 to 1050 nm. The NIR system can be used forreal-time monitoring of fat, protein, lactose, somatic cell count, and milk urea nitrogen during milking with sufficient precision and accuracy. By using this NI Rsystem, dairy farm management could proceed to the next step in the transition to artificial intelligence in dairy farming based on information of each individual cow.