1,720,973 research outputs found
Inter-disciplinary approaches in food safety to expand mycotoxin detection, compare bacterial transfer rates, and forecast fungal inoculum under climate change
No full textFood safety research is complex and interdisciplinary as it involves considerations from pre-production through final home preparation of a food product which passes a long chain of food processing where each stage has potential opportunities for the contamination. The aim of this dissertation was to develop novel methods which could generalize to future food safety issues regarding contamination. This goal was approached by (1) extending a protocol for detection of ochratoxin A into food matrices where phenolic compounds are present, (2) investigation into how bacterial transfer is affected by both hand washing and glove use, (3) interpreting sources of variability in a fungal inoculum source capable of producing deoxynivalenol, and (4) forecasting future shifts in fungal inoculum under climate change. Ochratoxin A (OTA) is a fungal metabolite and putative carcinogen which can contaminate a variety of foods such as cereals, wine, and nuts. Commercial ELISA kits are known to give false-positive results for OTA concentrations when phenolic compounds are present. Pistachios represent a food matrix rich in phenolic compounds potentially contaminated with OTA, and polyvinylpolypyrrolidone (PVPP) was incorporated during extraction of OTA using a commercial ELISA protocol. HPLC methods were used to confirm that PVPP does not interact with OTA and the cross-reactivity of extracts also decreased with increasing PVPP application. To assess bacterial transfer from hands to gloves and to compare bacterial transfer rates to food with different soap washing times and glove use, participants’ hands were artificially contaminated with a ~109 CFU inoculum of Enterobacter aerogenes B199A. Different soap rubbing times (0, 3, and 20 s), glove use, and tomato dicing activities were followed. Different soap rubbing times did not significantly change the amount of bacteria recovered from participants’ hands. Both glove use and adequate hand washing are necessary to reduce bacterial cross-contamination as increasing soap washing time decreased the incidence of bacterial contamination recovered from outside glove surfaces (p < 0.05) and dicing tomatoes with bare hands after 20 s of soap rubbing transferred significantly (p < 0.01) less bacteria to tomatoes compared with bare hands after 0 s of soap rubbing. The plant pathogen Fusarium culmorum represents an inoculum source capable of contaminating grains with deoxynivalenol (DON) in the Inland Northwest (INW) region of the United States. A multilevel modelling approach utilizing varying intercepts for different sampling quadrats, fields, and iterations in the dataset was performed to characterize variability in isolation frequency of F. culmorum collected during a two-year soil survey. Differences in the isolation frequency of F. culmorum varied the most by sampled field followed by quadrat and iteration, respectively. Higher relative elevation within the sampling region of a field limited the amount of F. culmorum recovered. Isolation records were extended to incorporate the soil dilution factor and used to construct a multilevel climate model. Varying intercepts and slopes were assigned to each unique agricultural field and a weather-based proxy for soil moisture, termed atmospheric water balance (AWB) was used as a predictor variable. Values of AWB derived from downscaled global climate models were used to forecast future shifts in the proportion of F. culmorum across all sampled fields. Population densities of F. culmorum are forecasted to remain constant during the winter and spring but decrease over the summer and fall under climate change, with the magnitude differing across fields.doctoral, Ph.D., Food Science -- University of Idaho - College of Graduate Studies, 2019-1
HEAT STABILITY OF OCHRATOXIN A
No full textOchratoxin A (OTA) is a toxic and potentially carcinogenic fungal secondary metabolite found in a wide variety of agriculture commodities worldwide. It is stable under most food processing conditions. However, interaction of factors like temperature, moisture, pressure, and presence of food components affect its stability. Reduction of OTA was measured at different temperatures for variable heating times in aqueous buffer solutions. It was found that OTA stability was dependent on temperature, processing time, and pH. Greater than 90% reduction was achieved after 60 min of heating at 200C in pH 7 and 10 while only 60% was lost in pH 4. The extrusion study examined effects of moisture, temperature, screw speed, and die size on OTA reduction. It showed that die size and screw speed had significant effect on reduction. The total reduction ranged 0-28% with maximum being achieved at 180C, 250 rpm, 3mm and 20% moisture content.Thesis (M.S., Food Science) -- University of Idaho, 201
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The impact of degree of milling on the contents of rice bran lipids and gamma-tocotrienol
No full textThe purpose of this research was to study the impact of milling on total lipids and γ-tocotrienol concentrations in rice brans of Cheniere and Francis varieties. The brown rice obtained after dehulling was milled to 4%, 6%, 8% and 9% milling degrees. Total lipids were analyzed using AACC method and γ-tocotrienol was quantified by reverse phase HPLC. The results indicated that Cheniere had significantly higher contents of lipids and γ-tocotrienol than Francis at all degrees of milling (p≤0.05). It was also found that lipids and γ-tocotrienol content decreased with increasing milling degree from 4% to 9%. The lipid content of the bran at 4% milling was significantly higher than the bran at 9% milling. The lowest γ-tocotrienol content was found to be 344 μg/g bran in Cheniere and 331.1 μg/g bran in Francis. Thus, γ-tocotrienol rich bran could possibly be obtained by avoiding hard milling or 9% milling degree of brown rice
Recommended from our members
EFFICACIES OF SANITIZERS AGAINST LISTERIA MONOCYTOGENES AND SPOILAGE FUNGI IN SIMULATED DUMP TANK WATER
Full text linkListeria monocytogenes leads to foodborne outbreaks on fresh apples and apple products. Spoilage fungi such as Penicillium expansum cause blue mold in apples, leading to a large amount of food waste and economical loss. During commercial processing, harvested apples are first soaked in a dump tank and flume water system. To lower operational cost, the industry reuses water in dump tanks over several processing days, which leads to accumulations of microorganisms and organic matters. This practice increases potential risks of crosscontamination of the foodborne pathogens as well as spoilage microorganisms. To reduce the potential cross-contamination, the disinfectants such as chlorine or peroxyacetic acid are extensively used in dump tank water. However, little is known about the practical antimicrobial efficacy of these sanitizers used in dump tanks. This study evaluated antimicrobial efficacies of chlorine, peroxyacetic acid (PAA) against L. monocytogenes and spoilage fungi in simulated dump tank water (SDTW) at different levels of organic matters. Results showed that chlorine at v 25 ppm showed limited efficacy (~2.0-log10 CFU/ml after 5 min) against L. monocytogenes in SDTW regardless of organic matter levels. Anti-Listeria efficacy increased with increased concentrations and diminished by increased level of organic matters indicated by chemical oxygen demand (COD). Anti-Listeria efficacy of chlorine at 100 ppm was not significantly impacted at 1000 ppm COD but was reduced at 4000 ppm COD. Anti-Listeria efficacy of PAA increased with concentration and contact time, which was minimally influenced by the presence or level of organic matters. At 5 min and 4000 ppm COD, 40 ppm PAA resulted in over 8.0-log10 CFU/ml reduction of L. monocytogenes, which was higher than the 6.0-log10 CFU/ml caused by 100 ppm chlorine. However, compared to chlorine, PAA at maximum legal concentration, 80 ppm, had limited efficacy against spoilage fungi, leading to ~0.5-log10 CFU/ml after 5 min contact time. To impro
Healthcare foodservice workers' perceptions of supervisors' role modeling and enforcement behaviors as related to food safety
No full textStudy purpose was to investigate healthcare foodservice employee perceptions of: 1) supervisors' role modeling and enforcement of safe food handling behaviors and 2) supervisors' positive and negative feedback regarding employee work performance. Survey was developed by the researchers, validated and pilot tested. Participants included 122 workers and 21 supervisors at 5 healthcare facilities in north Texas. Overall workers and supervisors indicated similar positive perceptions of supervisor role modeling, enforcement and feedback behaviors. Spearman rho correlation analyses indicated that workers with more foodservice experience were less likely to perceive that supervisors monitored, enforced, and provided disciplinary action regarding safe food handling rules. They were also less likely to feel that if they did well, supervisors would reward them. Continued research in this area is needed to further identify the variables that most affect worker compliance with safe food handling procedures
Effect of non hydrogenated cottonseed oil on the flavor quality and stability of high oleic low linolenic canola oil during potato chip processing
No full textPotato chips fried in high oleic low linolenic canola oil (HOLLCA), non hydrogenated cottonseed oil (CSO), and HOLLCA-CSO blends (50-50 and 75-25) were evaluated by a sensory panel, before and after a 4 month storage which included 2 months of storage under light. Para-Anisidine values (pAV) did not increase significantly during storage, whereas the thiobarbituric acid (TBA) values increased significantly during storage in chips fried in cottonseed oil and 50-50 HOLLCA-CSO blend. The addition of CSO reduced the level of oleic acid from 73.75% to 63.09% (1:3 ratio) or 47.54% (1:1 ratio), while increasing e amount of linoleic acid from 16.37% to 25.75% (1:3 ratio) or 36.00% (1:1 ratio). Sensory evaluation showed that the intensity of fried flavor and off-flavors of potato chips were similar among oils and blends, and remained unchanged during storage. The overall likeability of HOLLCA fried chips was significantly improved by the addition of non hydrogenated cottonseed oil in 1:3 ratio. The flavor quality and TBA value of potato chips fried in 75-25 HOLLCA-CSO blend appear to fluctuate much less during storage than those of chips fried in 50-50 blend.
The addition of CSO to HOLLCA in 1:3 ratio did not significantly increase TBA value and TBA value of the resulting blend did not significantly increase during storage, indicating that potato chips fried in 75-25 HOLLCA-CSO blend can sustain a longer storage than those fried in cottonseed oil, without showing signs of flavor deterioration
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Food safety training in Texas school foodservice facilities in relationship to the implementation of a HACCP program
No full textDual DegreeThe purpose of this study was to investigate food safety training currently offered in Texas school foodservice facilities in relation to implementation of Hazard Analysis Critical Control Point (HACCP). A survey instrument was developed by the researcher, validated by school foodservice professionals and pilot tested. Online surveys and paper surveys were used to obtain data. Of 525 foodservice directors randomly chosen, 120 completed the survey and results were summarized and statistical analyses were conducted using Pearson's Product Moment Correlation and Analyses of Variance. Food safety training is currently being provided in school foodservice through different methods. A majority of school foodservice directors agreed with the effectiveness of food safety training, had favorable attitudes towards food safety training and faced few barriers to food safety training. Overall, this study concluded that most Texas school foodservice facilities have standard operating procedures and a HACCP plan in place
- …
