Vibrio vulnificus is an estuarine bacterium that can cause primary septicemia as well as other serious wound infections. Vibrio parahaemolyticus is a gram-negative, halophilic bacterium that may cause gastroenteritis, diarrhea, headache, vomiting, nausea, abdominal cramps and is the leading cause of gastroenteritis in United States. Consumption of raw oysters is believed to closely relate with infection with Vibrio vulnificus and Vibrio parahaemolyticus. All strains of V. parahaemolyticus produce tlh genes and the major virulence factors of V.parahaemolyticus are the tdh and trh genes. This study was conducted to determine if Vibrio vulnificus and Vibrio parahaemolyticus clinical and environmental strains display different behaviors at refrigeration temperature. The effects of three different temperature treatments were investigated in this study. In addition, the cold adaption behaviors of different gene-containing Vibrio parahaemolyticus in broth under three different temperatures 5, 8, and 10oC were also studied. Results obtained from this study showed clinical and environmental strains of Vibrio vulnificus and Vibrio parahaemolyticus in oysters had significant differences in growth and survival at specific days under different refrigeration temperature treatments. When different gene-containing Vibrio parahaemolyticus strains were stored at 5oC over 10 days, all strains were able to survive but not grow. At 8oC all of the V. parahaemolyticus strains were able to survive and grow. At 10oC, two of the V. parahaemolyticus strains survived and grew while the V. parahaemolyticus 132 X 5 strain survived but did not grow.

In this study, the effects of ozonation and the addition of amino acids on rice starches were determined in terms of pasting properties by using rapid visco-analyzer, thermal characteristics by using differential scanning calorimeter, crystallinity by using x-ray diffraction, and resistant starch yield. Results from viscosity analysis showed that the addition of lysine (6%) to ozonated Sigma rice starch significantly reduced peak viscosity (PV), minimum viscosity (MV), final viscosity (FV), and setback (SBK) by 918, 1024, 1023, and 105 cP, respectively. Moreover, it decreased pasting time, resulting in the faster swelling upon heating and less rigid gel formation upon cooling. The presence of lysine in ozonated white starch isolate (WSI) also significantly reduced all pasting properties and time to cook, and produced starch gel with the best cooking stability. The amylose content of Sigma rice starch was increased by ozone, and the enzymatic-gravimetric analysis indicated that the resistant starch yield was enhanced by more than 3% when rice starch was ozonated for 30 minutes. Moreover, the addition of leucine to ozonated starch showed the highest resistant starch formation (9.13%). Ozonation of Sigma rice starch and white starch isolate (WSI) reduced gelatinization temperature, amylose-lipid complex endothermic temperature and enthalpy, but increased 1st transition enthalpy. However, the presence of lysine (6%) increased gelatinization endotherm transition temperature but reduced 2nd transition enthalpy. Ozone treatment of Sigma rice starch induced B+V type XRD pattern and increased the relative crystallinity (RC), and addition of lysine showed A+B type XRD pattern and enhanced the RC further. In addition, ozonation caused some physical damage showing some broken small pieces of particles and distorted starch granules with both Sigma rice starch and white starch isolate.

Rice bran oil (RBO) contains 3-4% waxes (rice bran wax, RBW), which are composed of wax esters (WE), hydrocarbons, and other minor constituents. Saponified rice bran wax esters (RBWE) generate fatty acids, long chain alcohols, and phytosterols. Phytosterols and long chain fatty alcohols (policosanol) are known to reduce serum cholesterol and inhibit hepatic cholesterol synthesis. The yields and RBWE contents of RBO and RBW extracted from full-fat RB (FFRB) and defatted RB (DFRB) were determined using 6 different conditions with Soxhlet and Microwave-assisted extraction (MAE). The compositions of WEs from RBO and RBW were also compared. RBW was obtained from RBO by winterization and solvent fractionation. WEs were separated by chromatographic methods, and analyzed as intact WE using a mass analyzer. After saponification of WE, alcohols, sterols, and fatty acids were analyzed by GC. Crude FFRBO yields were not significantly different among the extraction methods, while MAE (isopropanol, 120°C) showed significantly higher DFRBO yields. DFRBOs had higher concentrations of crude RBW than FFRBOs, and hexane extractions showed higher crude RBW yields. Crude RBW yields from FFRB were higher than from DFRB, while refined RBW yields from FFRB and DFRB were more similar. The refined RBW yields by hexane extractions were much higher than those by isopropanol extractions, and DFRBOs showed higher refined RBW yields than FFRBOs. HPLC results indicated that most WE was contained in RBO raffinate, and around half of the refined RBW consisted of WE. The mass spectra showed that there were more long chain species in WE from RBW. GC results identified C13-C22 fatty acids and the major alcohols in WE from RBW appeared as C32 and C34. Six sterols were identified in WE from RBO. Results indicate that MAE with hexane is more efficient than Soxhlet for RBWE extraction. DFRB appears to have significant RBW content, which would make it an excellent source for potential commercial exploitation. This study established an efficient procedure for WE analysis as well as for alcohol/sterol separations from RBW for further biological experiments.

This study assessed the efficacy of the ozonation process in degrading aflatoxin in corn, and investigated the chemical reaction between aflatoxin and gaseous ozone. Ozonation (12-13 wt%) totally degraded aflatoxin B1 in a model system. Conversion of aflatoxin into polar compounds was observed during ozonolysis of 100 µg aflatoxin B1 in an aqueous environment and in solid form. Seven intermediate reaction products were separated by two-dimensional thin layer chromatography. HPLC analysis of ozonated AFB1 revealed the presence of six major peaks. MALDI-MS analysis detected compounds that have higher molecular weights than AFB1. The dichloromethane fraction contained compounds with molecular ion peaks at 459 and 439 m/z while the water fraction contained compounds with molecular ion peaks at 475 and 494 m/z, after ozonation for 50 sec and 60 sec, respectively. Biosynthesis of [14-C]-labeled aflatoxin B1 by Aspergillus flavus (A53, C50Aa) and sodium acetate-1,2-[14C] as a precursor yielded 339 µg of [14C]-AFB1 with a specific activity of 1.06 µCi/µmol (7548 dpm/µg). Corn kernels inoculated with Aspergillus flavus (A53, C50Aa) resulted in the production of grains contaminated with aflatoxin B1 (7452 ng/g) and aflatoxin B2 (704 ng/g). Modification of AFB1 after treatment with gaseous ozone was determined using [14C]-labeled AFB1. Ozonated and non-ozonated corn spiked with [14C]-AFB1 were evaluated and compared through a series of extraction, partition, and digestion procedures. Ozonation (9-10 wt%) resulted in 74% and 44% reduction of AFB1 and AFB2 levels, respectively. Radioactivity measured by liquid scintillation counting showed an increase in the percentage of radioactivity in more polar and aqueous solvents from ozonated corn compared with non-ozonated corn. These results suggested the formation of more polar and/or water soluble aflatoxin-related compounds from the reaction of ozone with AFB1. Based on these results, it is postulated that ozone attacked the double bond in the C8-C9 position and converted aflatoxin B1 into an aldehyde.

This research investigated the ability of blueberry anthocyanins to inhibit the uptake of N-retinyl-N-retinylidene ethanolamine (A2E) by retinal pigment epithelial (RPE) cells as quantified by pigment epithelial derived factor (PEDF) levels in RPE cells. The A2E was synthesized and identified by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Freeze dried blueberry powder of 50/50 blend (Tifblue/Rubel) anthocyanins were extracted by acetone and concentrated through chromatography. A RPE cell culture study investigating four treatments using a combination of 100 ìM A2E in DMSO and 100 ìg of blueberry anthocyanins in DMSO was tested. The treatments included: (A) control RPE cells; (B) RPE cells incubated with A2E for 2 hours with blue light illumination for 20 minutes; (C) RPE cells incubated with blueberry anthocyanins for 24 hours and incubated with A2E for 2 hours with blue light illumination for 20 minutes; and (D) RPE cells incubated with blueberry anthocyanins for 24 hours, then incubated with A2E for 2 hours with blue light illumination for 20 minutes and then treated with blueberry anthocyanins again. All treatments were incubated for seven days at 37°C with 5% CO2 and samples were collected on days 1, 3, 5 and 7. The supernatant of the RPE cells were collected and the protein concentration determined and normalized. The PEDF values were determined using a PEDF enzyme linked immunosorbant assay (ELISA). The average PEDF results indicated that blueberry anthocyanins promoted and maintained PEDF levels when compared to control RPE cells and RPE cells treated with A2E for 1, 3 and 5 collection days. Treatments C and D had significantly (p<0.05) higher PEDF levels of 10.17 and 10.14 ng PEDF per mg protein than treatment B of 5.750 ng PEDF per mg protein for day 1. Treatment D had a significantly (p<0.05) higher PEDF level of 13.76 ng PEDF per mg protein than the other treatments at day 3 and was significantly higher at 12.51 ng PEDF per mg protein than treatment A at 8.947 ng PEDF per mg protein on collection day 5. There is evidence that blueberry anthocyanins protected RPE cells from oxidation as measured by PEDF values.

Vibrio parahaemolyticus is a marine bacterium which is the leading cause of bacterial gastroenteritis due to consumption of raw or undercooked bivalve molluscan shellfish in United States and is considered an important seafood-borne pathogen throughout the world. The conventional methods for enumerating this bacteria from seafood is laborious and time consuming, hence the objective of our study was to develop antibody based method which would be sensitive, user-friendly and less time consuming to detect and enumerate Vibrio parahaemolyticus from oysters. In order to condense time and material two rapid and specific antibody based test methods were developed. In the first method, monoclonal antibodies were produced against the polar flagella of Vibrio parahaemolyticus. The monoclonal antibody was employed in Immunomagnetic separation (IMS) protocol and was then coupled with Real-time PCR (q-PCR). IMS coupled to q-PCR was able to detect bacterial numbers in less than 3 hrs with a sensitivity of 1,000 CFU/g of oyster homogenate. In the second method anti-hemolysin serum was produced and employed in Direct colony immunoblot (DCI) protocol to detect pathogenic Vibrio parahaemolyticus. DCI when compared with the currently used conventional method, DNA hybridization (DNAH) showed good correlation and was a faster and simpler method requiring less equipment and stringent laboratory conditions than DNAH. From our results we have found that IMS+q-PCR or DCI could be an useful addition to the methods available for enumerating pathogenic V. parahaemolyticus in seafood.

Shrimp is one of the most common seafoods and a favorite among consumers. Like any other food there are safety concerns about shrimp. Listeria species, Salmonella species, Clostridium species and Vibrio species are among the pathogens of prime importance. Most of these pathogens can be eliminated by cooking. However, the extent of cooking and temperatures greatly influence the safety of these foods. The current study is focused on the determination of minimum cooking temperatures for shrimp to eliminate Listeria species, Salmonella species and Vibrio species. Shrimp were surface inoculated with the three different species mentioned above to about 5.00 log CFU/g of shrimp and then incubated for two days. Shrimp samples were treated at five different temperatures on days 0 (day of inoculation), 1 and 2 by boiling. The effects of heat treatments by boiling on bacterial counts were determined by plating and calculating the log CFU/g reduction for each temperature. The experiment was repeated with different temperatures for each bacterium until the bacterial load in the shrimp was at non-detectable levels. The internal temperature of 85oC was the lowest temperature that was needed to kill all the bacteria tested. Vibrio species were less resistant to heat with bacterial counts reaching non-detectable levels at 55oC. 75oC was the minimum temperature required to eliminate Salmonella species, while Listeria species showed highest resistance up to 85oC. This study is mainly intended to design a simple, easy and unbiased consumer guide for cooking shrimp to enhance safety while handling and cooking them at home. This can also serve as a guide for manufacturers of ready-to-eat shrimp products while designing and planning CCPs in HACCP plans during production.

Amino acids were previously found to modify starch functionalities and potentially increase starch utilization. The effect of amino acids at different pH levels on the pasting properties, thermal characteristics, and resistant starch (RS) formation of rice starch was investigated. Prior to the analyses, pretreatment of starch was done by adding amino acid (aspartic acid, leucine, lysine and tyrosine) at 6% dry weight basis and dispersing the mixture in distilled water, solutions adjusted with HCl and NaOH to pH 4, 7 and 10, and buffers of acetate, phosphate and carbonate at the same pH levels, respectively. Samples in HCl/NaOH solutions were mixed at room temperature and at 40+2oC. The slurries were stored at -80oC and lyophilized. Lysine and aspartic acid raised the breakdown (BD) and reduced the total setback (TSB) at all pHs using HCl/NaOH, with aspartic acid exhibiting the greater effect. Lysine shortened the pasting time (PTime) without affecting the peak temperature (PT) and increased the peak and conclusion temperatures with or without pH adjustment. Tyrosine in pH 10 solution reduced the PTime. In buffers, lowering of the peak viscosity, PTime and PT was observed, but was mainly attributed to the buffers. Heating at 40+2oC likewise decreased the paste viscosities and gelatinization temperatures, but raised the PTime and PT, with lysine having the most profound effect. Samples added with aspartic acid and leucine generally caused substantial increases in RS yields. No conclusive results on RS formation were obtained based on effect of charges. Therefore, charges in additives played an important role in altering pasting and thermal properties of rice starch, but not in controlling RS formation. To determine effect of hydroxyl-containing amino acid, starch was added with tyrosine, gelatinized, and lyophilized. The sample in pH 10 solution (HCl/NaOH) had higher BD and TSB than native starch. RS yields of gelatinized samples were negatively correlated to treatment in pH 10 solution. Compared to pretreated samples, gelatinized samples had higher paste viscosities and RS values. In conclusion, amino acids in combination with pH treatments can be used to alter rice starch functionalities, and may consequently enhance formation of RS.

The sweet potato is a vegetable containing high levels of different vitamins and minerals, needed to protect the body against disease. This study focused on starch found in the Beauregard and Evangeline sweet potatoes and observed the effect of pH and amino acid additives altering the functionality of starch. These modifications of the Beauregard and Evangeline sweet potato starches will also be done to determine if an increase in resistant starch and slowly digestible starch is found. Beauregard and Evangeline starches had similar gelatinization temperature and the two starches required the same amount of energy to gelatinize. In Freeze-dried Beauregard starch, peak temperature decreased with pH treatments and pH10 decreasing peak temperature to 68.7°C. Histidine at pH10 decreased peak temperature to 69.7°C. In Evangeline freeze-dried starch, histidine significantly decreased peak temperature, especially at pH10 for one hour (73.17°C) compared to native. In Beauregard oven-dried starch, the control significantly lowered peak temperature compared to the native. pH3 and 10 were significant in lowering peak temperature of the starch. Lysine and histidine were significant amino acids in decreasing peak temperature. In Evangeline oven-dried starch, histidine at pH3 and pH10 were significant for decreasing peak temperature compared to the native starch. Positively charge amino acids along with pH treatments caused significant alterations in pasting properties of both Beauregard and Evangeline sweet potato starches. Oven-dried starch was more responsive to changes in pasting characteristics than freeze-dried sweet potato starch. Evangeline oven-dried sweet potato starch, histidine lowered breakdown and with the addition of pH10 treatment breakdown decreased even further, increasing its stability to shear during cooking. There was a trend towards increased RS with amino acids added at pH3 or pH10 versus pH3 or pH10 alone, especially for lysine and histidine. Freeze-dried Beauregard starch SDS showed large increases with pH3 for 1 hour and lysine and histidine at pH3 for 1 hour. SDS content increased in oven-dried Beauregard starch the most with arginine at pH3. Freeze-dried Evangeline starch SDS content increased the greatest with histidine at pH3. SDS content increased the greatest with lysine at pH3 for oven-dried Evangeline starch.

The incidence of foodborne outbreaks linked to fresh produce has increased in the United States. Particularly noteworthy was the 2006 Escherichia coli O157:H7 outbreak associated with pre-packaged baby spinach. Factors affecting the contamination of spinach leaves with E. coli O157:H7 are not yet well understood. This study aimed to determine whether E. coli O157:H7 would be present in the aerial leaf tissue of a growing spinach plant when introduced at various plant maturities and different inoculum levels in the growth media in a greenhouse setting. Spinach seeds of a standard commercial variety were sown individually in 8-inch pots, watered daily and fertilized weekly after germination. Two levels (103 and 107 CFU) of an E. coli O157:H7 green fluorescent protein (GFP)-expressing strain were introduced into the plant growth media on a weekly basis after germination. Inoculated spinach plants were examined weekly for the presence of E. coli O157:H7 on leaves and in surrounding growth media. Among 120 spinach plant samples examined for internal leaf contamination, only one yielded positive result. Surface leaf contamination occurred occasionally and clustered between 4 to 5 weeks of age, but not among leaves younger than 3 weeks of age. Additionally, when inoculated at 107 CFU level, the E. coli O157:H7 GFP strain survived the entire cultivation period although with gradually reduced levels. The experiments demonstrated that internalization of E. coli O157:H7 of growing spinach plant leaves under greenhouse conditions was a rare event, but surface contamination did occur, primarily when the plants reached 3 weeks of age. The study provided important data to further assess the association between spinach age and potential contamination of E. coli O157:H7.