A gaseous acetic acid treatment to disinfect fenugreek seeds and black pepper inoculated with pathogenic and spoilage bacteria.

Contamination of spices by pathogenic and/or spoilage bacteria can be deleterious to consumer's health and cause deterioration of foods, and inactivation of such bacteria is necessary for the food industry. The present study examined the effect of gaseous acetic acid treatment in reducing Escherichia coli O157:H7, Salmonella Enteritidis and Bacillus subtilis populations inoculated on fenugreek seeds and black pepper. Treatment with gaseous acetic acid at 0.3 mmol/L, 0.6 mmol/L and 4.7 mmol/L for 1-3 h significantly reduced the populations of E. coli O157:H7 and Salmonella Enteritidis on black pepper and fenugreek seeds at 55 °C (p < 0.05). The gas treatments at 4.7 mmol/L were more effective in inactivating the pathogens than the treatment at 0.3 mmol/L. An approximately 5.0 log reduction was obtained after 3 h of treatment with 4.7 mmol/L acetic acid. No significant reductions in the population of B. subtilis spores inoculated on fenugreek seeds and black pepper were obtained after the gas treatments at 0.3 mmol/L or 0.6 mmol/L (p > 0.05). However, the gas treatment at 4.7 mmol/L significantly reduced B. subtilis spores (p < 0.05), and 4.0 log CFU/g and 3.5 log CFU/g reductions on fenugreek seeds and black pepper, respectively, were obtained after 3 h of treatment.

Large-scale gaseous acetic acid treatment to disinfect alfalfa seeds inoculated with Escherichia coli.

Most outbreaks of foodborne illness related to sprout consumption are ascribed to bacterial contamination of its seeds, and they need disinfection before sprouting. Recently, gaseous acetic acid (GAA) treatment received great attention as a method for seed disinfection. In this study, the effect of GAA treatment on alfalfa seed disinfection was evaluated in a large-scale device to simulate practical applications. Alfalfa seeds (3 kg) inoculated with Escherichia coli were treated with 8.7% (vol/vol) GAA at 55°C for 1-3 h. The population of E. coli was significantly reduced (p<0.05), and the reduction was larger with longer exposure times. After 3-h treatment, a maximum decrease by more than 5 log colony-forming units/g was observed. The germination ratio of alfalfa seeds was not affected by the treatments under all the conditions. The results indicated that the GAA treatment has a potential for practical application to reduce the risk of foodborne illness caused by consumption of sprouts.

Disinfection of radish and alfalfa seeds inoculated with Escherichia coli O157:H7 and Salmonella by a gaseous acetic acid treatment.

Abstract The majority of seed sprout-related outbreaks have been associated with Escherichia coli O157:H7 and Salmonella. Therefore, we aimed to find an effective method to inactivate these organisms on seeds before sprouting. Treatment with 8.7% (v/v) acetic acid at 55°C for 2-3 h reduced the population of E. coli O157:H7 and Salmonella inoculated on alfalfa (Medicago sativa L.) and radish seeds (Raphanus sativus L.) by more than 5.0 log CFU/g, and a longer treatment time completely eliminated the E. coli O157:H7 population. The E. coli O157:H7 populations were reduced to an undetectable level with a gaseous acetic acid treatment for 48 h. After enrichment, no E. coli O157:H7 were found in the alfalfa and radish seeds (25 g). However, these treatments were unable to eliminate Salmonella in both seed types. No significant difference between the germination rates of treated alfalfa seeds and control seeds was found, and germination rates greater than 95% were obtained for the radish seeds. Although chlorine washing is commonly used for seed decontamination, chlorine washing at 200 and 20,000 ppm resulted in a reduction of pathogens by less than or equal to 3 log CFU/g. Therefore, these results suggested that gaseous acetic acid is more effective than chlorine washing in controlling pathogenic bacteria on sprout seeds.

Decontamination effect of milling by a jet mill on bacteria in rice flour.

The decontamination effect of milling by a jet mill was investigated by counting the number of bacteria in brown and white rice flour with mean particle diameters of 3, 20, and 40µm prepared by the jet mill. In the jet mill, the particles are crushed and reduced in size by the mechanical impact caused by their collision. Although the brown and white rice grains were contaminated with approximately 10(6) and 10(5) CFU/g bacteria, the microbial load of the rice flour decreased as the mean particle diameter decreased, ultimately decreasing to approximately 104 and 103 CFU/g in the brown and white rice flour. The temperature and pressure changes of the sample were not considered to have an effect on reducing the bacterial count during the milling. Hence, it was thought that the rice flour was decontaminated by other effects.

"Nata Puree," a Novel Food Material for Upgrading Vegetable Powders, Made by Bacterial Cellulose Gel Disintegration in the Presence of (1,3)(1,4)-ß-Glucan.

Pulverization is a potentially powerful solution for the resource management of surplus- and non-standard agricultural products, maintaining their nutritional values for long and ensuring their homogeneity, whereas their original textures could disappear to narrow the application ranges. Therefore, new technologies should be developed for reconstructing the powders to provide them with new physical characteristics. Herein, we developed a novel food material, nata puree (NP), by nata de coco (bacterial cellulose gel) disintegration with a water-soluble polysaccharide using a household blender. The process worked well with (1,3)(1,4)-ß-glucan (BGL) as the polysaccharide, which could be substituted with barley extract. Lichenase treatment of the NP dramatically modified its physical properties, suggesting the importance of the BGL polymeric forms. NP exhibited distinct potato powder and starch binding activities, which would be attributed to its interactions with the cell wall components and a physical capture of powders by the NP network, respectively. NP supplementation into the potato paste improved its firmness and enabled its printable range shift for 3D food printing to a lower powder-concentration. NP also promoted the dispersion of powders in its suspension, and designed gelation could also be successfully performed by the laser irradiation of an NP suspension containing dispersed curdlan and turmeric powders. Therefore, NP could be applied as a powder modifier to a wide range of products in both conventional cooking, food manufacturing, and next generation processes such as 3D food printing.

Scale-up seed decontamination process to inactivate Escherichia coli O157:H7 and Salmonella Enteritidis on mung bean seeds.

A majority of the seed sprout-related outbreaks have been associated with Escherichia coli O157:H7 and Salmonella spp. Therefore, it is necessary to find an effective method to inactivate these microorganisms on the seeds before sprouting. When treatment with hot water at 85 degrees C for 40 sec followed by dipping in cold water for 30 sec and soaking into chlorine water (2000 ppm) for 2 h was performed, no viable pathogens were found in the enrichment medium and during the sprouting process. The germination yield of the seed was not affected significantly (p > 0.05). Therefore, these treatments could be useful for the decontamination method of mung bean seeds intended for sprout production.

Combined effect of low-dose irradiation and acidified sodium chlorite washing on Escherichia coli O157:H7 inoculated on mung bean seeds.

The effect of low-dose irradiation (0.75 and 1.5 kGy) in combination with acidified sodium chlorite (ASC) on the reduction of Escherichia coli O157:H7 on mung bean seeds was examined. Washing with ASC (0.2, 0.5, 0.8, and 1.2 g/L sodium chlorite and 1.0 g/L citric acid) for 2 h reduced the E. coli O157:H7 population from 5.2 to 2.3-3.3 log CFU/g, depending on the concentrations of sodium chlorite. Gamma ray irradiation at 0.75 and 1.5 kGy resulted in reductions of about 1.8 and 2.8 log CFU/g, respectively. Therefore, a single treatment with ASC washing or gamma ray irradiation at 0.75 or 1.5 kGy could not achieve the complete elimination of E. coli O157:H7 on mung bean seeds. Conversely, low-dose irradiation (0.75 and 1.5 kGy) followed by washing with ASC (0.5-1.2 g/L) reduced the population of E. coli O157:H7 to below the detection limit (<1 log CFU/g). However, E. coli O157:H7 was detected in most samples in the enrichment and germination studies. When the treatment order was reversed (ASC washing followed by low-dose irradiation), the E. coli O157:H7 population was also observed to be below the detection limit. Under this treatment, fewer samples (16.7%) were shown to be positive in the enrichment and germination studies, and complete elimination was not achieved. The germination rates of mung bean seeds were not affected by ASC washing and gamma irradiation; however, the yield and length of sprouts were decreased by gamma irradiation.

Effectiveness of acidified sodium chlorite and other sanitizers to control Escherichia coli O157:H7 on tomato surfaces.

The use of a suitable sanitizer can reduce the risk of produce-related foodborne illnesses. We evaluated the effectiveness of several sanitizers to reduce inoculated Escherichia coli O157:H7 on the surface of cherry tomatoes (Solanum lycopersicum var. cerasiform). Depending on the method of inoculation (dipping/spotting), each of 80 g (eight tomatoes) of inoculated cherry tomatoes was washed in 400 mL of sanitizer solutions or 400 mL distilled water for 5 minutes. The effectiveness of sanitizers on spot-inoculated E. coli O157:H7 on tomato surfaces was found higher than on dip-inoculated tomatoes. Washing with water or chlorine water (0.1 g/L as free chlorine) could reduce 1.3 log CFU/g of E. coli O157:H7 in dip-inoculated (6.8 log CFU/g) tomatoes. Washing with lactic acid (LA) solution (1.0 g/L), phytic acid solution (1.0 g/L), calcinated seashells (oyster/sakhalin surf clam), and 1.0 g/L chitosan in 0.5 g/L LA (Chito) did not exhibit a significant higher effectiveness than that of water wash alone (1.0 log CFU/g). Acidified sodium chlorite (ASC) solution prepared from 0.5 g/L of sodium chlorite and 1.0 g/L LA or phytic acid reduced 3.5 log CFU/g of E. coli O157:H7 in dip-inoculated tomato surfaces. ASC (0.5 g/L of sodium chlorite and 1.0 g/L of LA) wash followed by a second wash with LA exhibited an additional sanitary effectiveness compared to a single wash with ASC. However, washing with ASC followed by a second wash with Chito exhibited an additional 1.0 log CFU/g reduction compared to a secondary wash with water. No significant difference of color, taste, and texture was observed among the washed cherry tomatoes.

Effectiveness of superheated steam and gas catalytic infrared heat treatments to inactivate Salmonella on raw almonds.

The majority of the almond-related outbreaks have been associated with Salmonella. Therefore, it is necessary to find an effective method to inactivate these organisms on the raw almond before distribution in the market. This study was conducted to assess the effectiveness of superheated steam (SHS) treatments followed by catalytic infrared (IR) heat treatment to inactivate Salmonella populations on raw almond and to determine the effect of these treatments on the quality of raw almond. It has been found that SHS treatment for 70 seconds followed by catalytic IR heat treatment for 70 seconds was able to reduce 5.73 +/- 0.11 log CFU/g Salmonella population, and no survivors were found in the enrichment medium. The overall visual quality parameters of both treated and nontreated almonds were found within the acceptable limit. Therefore, SHS treatments for 70 seconds followed by catalytic IR heat treatment for 70 seconds could be an effective decontamination method for raw almonds.

Efficacy of chlorine and acidified sodium chlorite on microbial population and quality changes of spinach leaves.

Efficacy of washing with distilled water, chlorine solution, and acidified sodium chlorite (ASC) solution on populations of microorganisms on spinach leaves was evaluated. Washing with chlorine (100 mg/L) and ASC (sodium chlorite, 15 mg/L; citric acid, 200 mg/L) resulted in significant population reduction (1.1-1.9 log CFU/g) of aerobic microflora, coliform, and Escherichia coli O157:H7 (p < 0.05). There was no remarkable difference in decontamination efficacy between chlorine and ASC solution. In recent years, several sodium chlorite chemicals have been commercially available, and no difference in decontamination efficacy among the chemicals was observed when same concentration of sodium chlorite and citric acid were used. In addition, the reduction of E. coli O157:H7 population was influenced depending on the inoculation method and type of washing. It has been seen that dip-inoculated spinach leaves showed lower reduction than that of spot-inoculated spinach. After washing, populations of aerobic microflora, coliform, and E. coli O157:H7 were increased during storage at 10 degrees C, and washing condition before storage did not affect the subsequent increases in microbial population. Color of spinach leaves washed with ASC solution was not different from the color of those washed with water or chlorine solution, and washing with ASC solution was concluded to has no effect on appearance of spinach leaves.

Effectiveness of sanitizers, dry heat, hot water, and gas catalytic infrared heat treatments to inactivate Salmonella on almonds.

The majority of almond-related foodborne outbreaks have been associated with Salmonella. Therefore, it is necessary to find an effective method to inactivate these organisms on raw almond prior to market distribution. This study was conducted to assess the effectiveness of sanitizers (strong or mild electrolyzed water, ozonated water, and distilled water), dry heat treatment, and hot water treatments followed by catalytic infrared (IR) heat treatment to inactivate Salmonella populations on raw almond. Raw almonds inoculated with four-strain cocktails of Salmonella were treated either by soaking in different chemical sanitizers or with dry heat and/or hot water for various periods of time followed by catalytic IR heat treatment for 70 seconds. The treated seeds were then assessed for the efficacy of the treatment in reducing populations of the pathogens. After inoculation and air-drying, 5.73 +/- 0.12 log colony-forming units (CFU)/g Salmonella were detected in nonselective medium. Sanitizer treatment alone did not show significant reduction in the Salmonella population, but in combination with IR drying it reduced the population to 3.0 log CFU/g. Dry heating at 60 degrees C for 4 days followed by IR drying for 70 seconds reduced the Salmonella population an additional 1.0 log CFU/g. Hot water treatments at 85 degrees C for 40 seconds followed by IR drying for 70 seconds reduced pathogens to an undetectable level by direct plating, but not by enrichment.

Distribution of radioactive cesium ((134)Cs Plus(137)Cs) in a contaminated Japanese soybean cultivar during the preparation of tofu, natto, and nimame (Boiled Soybean).

We investigated the fate of radioactive cesium ((134)Cs plus (137)Cs) during the production of tofu, natto, and nimame (boiled soybean) from a contaminated Japanese soybean cultivar harvested in FY2011. Tofu, natto, and nimame were made from soybean grains containing radioactive cesium (240 to 340 Bq/kg [dry weight]), and the radioactive cesium in the processed soybean foods and in by-product fractions such as okara, broth, and waste water was measured with a germanium semiconductor detector. The processing factor is the ratio of radioactive cesium concentration of a product before and after processing. For tofu, natto, nimame, and for the by-product okara, processing factors were 0.12, 0.40, 0.20, and 0.18, respectively; this suggested that these three soybean foods and okara, used mainly as an animal feed, can be considered safe for human and animal consumption according to the standard limit for radioactive cesium of soybean grains. Furthermore, the ratio of radioactive cesium concentrations in the cotyledon, hypocotyl, and seed coat portions of the soybean grain was found to be approximately 1:1:0.4.

Dynamics of radioactive cesium (134Cs and 137Cs) during the milling of contaminated Japanese wheat cultivars and during the cooking of udon noodles made from wheat flour.

The fate of radioactive cesium ((134)Cs plus (137)Cs) during the milling of contaminated Japanese wheat cultivars harvested in FY2011, and during the cooking of Japanese udon noodles made from the wheat flour, was investigated. Grain samples containing various radioactive cesium concentrations (36.6 to 772 Bq/kg [dry weight]) were milled using a laboratory-scale test mill to produce eight fractions: three break flours (1B, 2B, and 3B), three reduction flours (1M, 2M, and 3M), bran, and shorts. The concentrations of radioactive cesium were found to be highest in the bran fractions of all the samples tested, with 2.3- to 2.5-fold higher values than that of the whole grain. Shorts contained radioactive cesium levels similar to that of the whole grain. In contrast, radioactive cesium concentrations in other fractions were found to be less than half the concentration in whole grain. The average processing factor (PF) value calculated for patent flour (0.401 ± 0.048), made from the mixture of 1B, 2B, 1M, and 2M for human consumption, or for low-grade flour (0.467 ± 0.045), made from the mixture of 3B and 3M, was found to be less than 0.5; whereas the average PF value (2.07 ± 0.232) for feed bran (mixture of bran and shorts), which has been used mainly as livestock feed in Japan, was over 2.0. Boiling udon noodles (made from patent flour) resulted in a substantial reduction (>70 % of initial amount) of radioactive cesium. Moreover, radioactive cesium was reduced further (<10 % of the initial amount) in the subsequent rinsing process, and the PF value of boiled noodles was recorded as 0.194. These results demonstrated that patent flour containing radioactive cesium can be made safe for human consumption by adopting the standard limit for radioactive cesium in wheat grain and that radioactive cesium in udon noodles is substantially reduced by cooking.

[Food protective property of new liquid food container PID (Pouch in Dispenser) for microbes].

We examined the content protection characteristics of the PID (Pouch in Dispenser) when it was used in the usual manner and when it was polluted artificially. When the PID was used in the usual manner, the nozzle was opened, and experiments were carried out with and without air-blowing. The invasion of bacteria into the PID was not detected. Also, no bacteria were detected in the material poured from the nozzle of the PID. When 3 strains of bacteria suspensions were intentionally smeared on the nozzle of the PID, invasion of bacteria was observed. When the PID was wiped with a dirty cloth, no invasion of bacteria into the PID was detected. It may be necessary to label the PID with the instruction that the nozzle should not be touched. The effected of changes in the water activity and pH, and the preservatives used, may also need to be considered, depending on the contents in the PID.

Detection of irradiated food using 2-alkylcyclobutanones as markers: verification of the european committee standardization method EN1785 for the detection of irradiated food containing lipids.

2-Alkylcyclobutanones (ACBs) are specific radiolytic products in irradiated lipid-containing food and can be used to detect irradiation of foodstuffs. EN1785, a European Committee Standardization Method, can detect 2-dodecylcyclobutanone (DCB) and 2-tetradecylcyclobutanone (TCB), which are ACBs, using GC/MS, thereby allowing judgement as to whether foodstuffs have been irradiated. In this study, the performance of EN1785 as a qualitative test in a single laboratory was evaluated and its applicability to beef, pork, chicken and salmon was verified. In the performance evaluation test, lipids extracted from unirradiated food using the Soxhlet extraction method were used as negative samples. Further, negative samples, to which DCB and TCB were added at 0.05 µg/g lipid (equivalent to the amount generated in food when irradiated at 0.5 kGy or more), were used as positive samples. For each food type examined, 4 negative and 16 positive samples were analyzed by EN1785 to verify the method's ability to detect irradiation. All of the negative samples were judged negative and all of the positive samples were judged positive. Thus, the method should be able to detect irradiation in beef, pork chicken and salmon irradiated at 0.5 kGy or higher. Next, to confirm that this is the case, the same types of food examined above, both unirradiated and irradiated at doses of 0.5-4 kGy, were analyzed by the method. All of the unirradiated samples were judged negative and all of the irradiated samples were judged positive. In a laboratory different from the one where the aforementioned evaluation was conducted, a performance evaluation test was carried out. Blind coded samples, including unirradiated and irradiated samples, were then analyzed in the laboratory according to EN178S. Ten samples (2 unirradiated and 8 irradiated samples) were analyzed for each type of food and the verified method was found to be 100% accurate. Even after the irradiated foodstuffs had been frozen for 6-9 months, it was still possible to judge whether the foodstuffs had been irradiated or not using the EN1785 method.