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Papers by Rachel Lange
OF DISSERTATION Rachel Pauline Lange The Graduate School University of Kentucky 2007 ESSAYS IN HE... more OF DISSERTATION Rachel Pauline Lange The Graduate School University of Kentucky 2007 ESSAYS IN HEALTH ECONOMICS _____________________________ ABSTRACT OF DISSERTATION _____________________________OF DISSERTATION _____________________________ A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the College of Business and Economics at the University of Kentucky By Rachel Pauline Lange Washington, DC Director: Dr. Glenn Blomquist, Professor of Economics and Public Policy Lexington, Kentucky 2007 Copyright © Rachel Pauline Lange 2007 ABSTRACT OF DISSERTATIONOF DISSERTATION ESSAYS IN HEALTH ECONOMICS Health and health care are dominant economic and political issues in the United States and many other countries. This dissertation contains two essays addressing different subjects within the field of health economics. The first essay is labor market oriented: “An Economic Analysis of the Effects of Obesity on Wages.” It examines the ...
Available at SSRN 992766, 2007
Abstract: Rationale: Obesity has become a very serious issue in the United States, where, accordi... more Abstract: Rationale: Obesity has become a very serious issue in the United States, where, according to the Centers for Disease Control and Prevention, about 60% of the American adult population is overweight. In the United States, several economists have connected ...
Federal regulations stipulate that food products be protected against physical, chemical and micr... more Federal regulations stipulate that food products be protected against physical, chemical and microbial contamination during transportation and holding. An expert opinion elicitation was conducted to assess food safety hazards and preventive controls associated with the transportation and holding of food commodities. Frequency and severity risk rankings suggest five food safety hazards of greatest concern across all modes of transport: (1) lack of security; (2) improper holding practices for food products awaiting shipment or inspection; (3) improper temperature control; (4) cross-contamination; and (5) improper loading practices, conditions, or equipment. Factor analysis suggests that "in-transit" and "organizational" risk factors might explain the relationships among the various food safety hazards. Raw seafood, raw meat and poultry, and refrigerated raw and ready-to-eat foods have the highest overall risk (in descending order) across all modes of transit. Our analysis also identified a range of preventive controls that may help eliminate/mitigate the risks to food during transport and storage, including: employee awareness and training, management review of records, and good communication between shipper, transporter and receiver.
Journal of Macromolecular Science, Part A, 2016
Environmental Microbiology, Mar 1, 2011
The near ubiquitous distribution of nifH genes in sediments sampled from 14 high-temperature (48.... more The near ubiquitous distribution of nifH genes in sediments sampled from 14 high-temperature (48.0-89.0°C) and acidic (pH 1.90-5.02) geothermal springs in Yellowstone National Park suggested a role for the biological reduction of dinitrogen (N 2) to ammonia (NH 3) (e.g. nitrogen fixation or diazotrophy) in these environments. nifH genes from these environments formed three unique phylotypes that were distantly related to acidiphilic, mesophilic diazotrophs. Acetylene reduction assays and 15 N2 tracer studies in microcosms containing sediments sampled from acidic and high-temperature environments where nifH genes were detected confirmed the potential for biological N 2 reduction in these environments. Rates of acetylene reduction by sedimentassociated populations were positively correlated with the concentration of NH 4 + , suggesting a potential relationship between NH 4 + consumption and N2 fixation activity. Amendment of microcosms with NH 4 + resulted in increased lag times in acetylene reduction assays. Manipulation of incubation temperature and pH in acetylene reduction assays indicated that diazotrophic populations are specifically adapted to local conditions. Incubation of sediments in the presence of a N 2 headspace yielded a highly enriched culture containing a single nifH phylotype. This phylotype was detected in all 14 geothermal spring sediments examined and its abundance ranged from~780 tõ 6800 copies (g dry weight sediment) -1 , suggesting that this organism may contribute N to the ecosystems. Collectively, these results for the first time demonstrate thermoacidiphilic N 2 fixation in the natural environment and extend the upper temperature for biological N 2 fixation in terrestrial systems.
Lpi Contributions, Apr 1, 2010
Structure of a key intermediate in H-cluster biosynthesis and [FeFe]-hydrogenase maturation revea... more Structure of a key intermediate in H-cluster biosynthesis and [FeFe]-hydrogenase maturation reveals unifying themes in complex biological Fe-S cluster biosynthesis.
BMC Biochemistry, 2015
Dual-specificity phosphatase-5 (DUSP5) plays a central role in vascular development and disease. ... more Dual-specificity phosphatase-5 (DUSP5) plays a central role in vascular development and disease. We present a p-nitrophenol phosphate (pNPP) based enzymatic assay to screen for inhibitors of the phosphatase domain of DUSP5. pNPP is a mimic of the phosphorylated tyrosine on the ERK2 substrate (pERK2) and binds the DUSP5 phosphatase domain with a Km of 7.6 ± 0.4 mM. Docking followed by inhibitor verification using the pNPP assay identified a series of polysulfonated aromatic inhibitors that occupy the DUSP5 active site in the region that is likely occupied by the dual-phosphorylated ERK2 substrate tripeptide (pThr-Glu-pTyr). Secondary assays were performed with full length DUSP5 with ERK2 as substrate. The most potent inhibitor has a naphthalene trisulfonate (NTS) core. A search for similar compounds in a drug database identified suramin, a dimerized form of NTS. While suramin appears to be a potent and competitive inhibitor (25 ± 5 μM), binding to the DUSP5 phosphatase domain more tightly than the monomeric ligands of which it is comprised, it also aggregates. Further ligand-based screening, based on a pharmacophore derived from the 7 Å separation of sulfonates on inhibitors and on sulfates present in the DUSP5 crystal structure, identified a disulfonated and phenolic naphthalene inhibitor (CSD (3) _2320) with IC50 of 33 μM that is similar to NTS and does not aggregate. The new DUSP5 inhibitors we identify in this study typically have sulfonates 7 Å apart, likely positioning them where the two phosphates of the substrate peptide (pThr-Glu-pTyr) bind, with one inhibitor also positioning a phenolic hydroxyl where the water nucleophile may reside. Polysulfonated aromatic compounds do not commonly appear in drugs and have a tendency to aggregate. One FDA-approved polysulfonated drug, suramin, inhibits DUSP5 and also aggregates. Docking and modeling studies presented herein identify polysulfonated aromatic inhibitors that do not aggregate, and provide insights to guide future design of mimics of the dual-phosphate loops of the ERK substrates for DUSPs.
Journal of bacteriology, 2010
The genetic context, phylogeny, and biochemistry of a gene flanking the H(2)-forming methylene-H(... more The genetic context, phylogeny, and biochemistry of a gene flanking the H(2)-forming methylene-H(4)-methanopterin dehydrogenase gene (hmdA), here designated hmdB, indicate that it is a new member of the radical S-adenosylmethionine enzyme superfamily. In contrast to the characteristic CX(3)CX(2)C or CX(2)CX(4)C motif defining this family, HmdB contains a unique CX(5)CX(2)C motif.
![Research paper thumbnail of Stepwise [FeFe]-hydrogenase H-cluster assembly revealed in the structure of HydAΔEFG](https://attachments.academia-assets.com/50331067/thumbnails/1.jpg)
](Nature, 2010
Figure 1 | Ball-and-stick representation of the H-cluster in [FeFe]hydrogenase from Clostridium p... more Figure 1 | Ball-and-stick representation of the H-cluster in [FeFe]hydrogenase from Clostridium pasteurianum 29 . The H-cluster is bound to the protein (tube representation) by four cysteine ligands of the [4Fe-4S]
Environmental Microbiology, 2011
The near ubiquitous distribution of nifH genes in sediments sampled from 14 high-temperature (48.... more The near ubiquitous distribution of nifH genes in sediments sampled from 14 high-temperature (48.0-89.0°C) and acidic (pH 1.90-5.02) geothermal springs in Yellowstone National Park suggested a role for the biological reduction of dinitrogen (N 2) to ammonia (NH 3) (e.g. nitrogen fixation or diazotrophy) in these environments. nifH genes from these environments formed three unique phylotypes that were distantly related to acidiphilic, mesophilic diazotrophs. Acetylene reduction assays and 15 N2 tracer studies in microcosms containing sediments sampled from acidic and high-temperature environments where nifH genes were detected confirmed the potential for biological N 2 reduction in these environments. Rates of acetylene reduction by sedimentassociated populations were positively correlated with the concentration of NH 4 + , suggesting a potential relationship between NH 4 + consumption and N2 fixation activity. Amendment of microcosms with NH 4 + resulted in increased lag times in acetylene reduction assays. Manipulation of incubation temperature and pH in acetylene reduction assays indicated that diazotrophic populations are specifically adapted to local conditions. Incubation of sediments in the presence of a N 2 headspace yielded a highly enriched culture containing a single nifH phylotype. This phylotype was detected in all 14 geothermal spring sediments examined and its abundance ranged from~780 tõ 6800 copies (g dry weight sediment) -1 , suggesting that this organism may contribute N to the ecosystems. Collectively, these results for the first time demonstrate thermoacidiphilic N 2 fixation in the natural environment and extend the upper temperature for biological N 2 fixation in terrestrial systems.
Applied and Environmental Microbiology, 2011
Subglacial sediments sampled from beneath Robertson Glacier (RG), Alberta, Canada, were shown to ... more Subglacial sediments sampled from beneath Robertson Glacier (RG), Alberta, Canada, were shown to harbor diverse assemblages of potential nitrifiers, nitrate reducers, and diazotrophs, as assessed by amoA, narG, and nifH gene biomarker diversity. Although archaeal amoA genes were detected, they were less abundant and less diverse than bacterial amoA, suggesting that bacteria are the predominant nitrifiers in RG sediments. Maximum nitrification and nitrate reduction rates in microcosms incubated at 4°C were 280 and 18.5 nmol of N per g of dry weight sediment per day, respectively, indicating the potential for these processes to occur in situ. Geochemical analyses of subglacial sediment pore waters and bulk subglacial meltwaters revealed low concentrations of inorganic and organic nitrogen compounds. These data, when coupled with a C/N atomic ratio of dissolved organic matter in subglacial pore waters of ϳ210, indicate that the sediment communities are N limited. This may reflect the combined biological activities of organic N mineralization, nitrification, and nitrate reduction. Despite evidence of N limitation and the detection of nifH, we were unable to detect biological nitrogen fixation activity in subglacial sediments. Collectively, the results presented here suggest a role for nitrification and nitrate reduction in sustaining microbial life in subglacial environments. Considering that ice currently covers 11% of the terrestrial landmass and has covered significantly greater portions of Earth at times in the past, the demonstration of nitrification and nitrate reduction in subglacial environments furthers our understanding of the potential for these environments to contribute to global biogeochemical cycles on glacial-interglacial timescales.
Applied and Environmental Microbiology, 2011
Previous research has shown that sequences of 16S rRNA genes and 16S-23S rRNA internal transcribe... more Previous research has shown that sequences of 16S rRNA genes and 16S-23S rRNA internal transcribed spacer regions may not have enough genetic resolution to define all ecologically distinct Synechococcus populations (ecotypes) inhabiting alkaline, siliceous hot spring microbial mats. To achieve higher molecular resolution, we studied sequence variation in three protein-encoding loci sampled by PCR from 60°C and 65°C sites in the Mushroom Spring mat (Yellowstone National Park, WY). Sequences were analyzed using the ecotype simulation (ES) and AdaptML algorithms to identify putative ecotypes. Between 4 and 14 times more putative ecotypes were predicted from variation in protein-encoding locus sequences than from variation in 16S rRNA and 16S-23S rRNA internal transcribed spacer sequences. The number of putative ecotypes predicted depended on the number of sequences sampled and the molecular resolution of the locus. Chao estimates of diversity indicated that few rare ecotypes were missed. Many ecotypes hypothesized by sequence analyses were different in their habitat specificities, suggesting different adaptations to temperature or other parameters that vary along the flow channel.
ABSTRACT Structure of a key intermediate in H-cluster biosynthesis and [FeFe]-hydrogenase maturat... more ABSTRACT Structure of a key intermediate in H-cluster biosynthesis and [FeFe]-hydrogenase maturation reveals unifying themes in complex biological Fe-S cluster biosynthesis.
Federal regulations stipulate that food products be protected against physical, chemical and micr... more Federal regulations stipulate that food products be protected against physical, chemical and microbial contamination during transportation and holding. An expert opinion elicitation was conducted to assess food safety hazards and preventive controls associated with the transportation and holding of food commodities. Frequency and severity risk rankings suggest five food safety hazards of greatest concern across all modes of transport: (1) lack of security; (2) improper holding practices for food products awaiting shipment or inspection;
OF DISSERTATION Rachel Pauline Lange The Graduate School University of Kentucky 2007 ESSAYS IN HE... more OF DISSERTATION Rachel Pauline Lange The Graduate School University of Kentucky 2007 ESSAYS IN HEALTH ECONOMICS _____________________________ ABSTRACT OF DISSERTATION _____________________________OF DISSERTATION _____________________________ A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the College of Business and Economics at the University of Kentucky By Rachel Pauline Lange Washington, DC Director: Dr. Glenn Blomquist, Professor of Economics and Public Policy Lexington, Kentucky 2007 Copyright © Rachel Pauline Lange 2007 ABSTRACT OF DISSERTATIONOF DISSERTATION ESSAYS IN HEALTH ECONOMICS Health and health care are dominant economic and political issues in the United States and many other countries. This dissertation contains two essays addressing different subjects within the field of health economics. The first essay is labor market oriented: “An Economic Analysis of the Effects of Obesity on Wages.” It examines the ...
Available at SSRN 992766, 2007
Abstract: Rationale: Obesity has become a very serious issue in the United States, where, accordi... more Abstract: Rationale: Obesity has become a very serious issue in the United States, where, according to the Centers for Disease Control and Prevention, about 60% of the American adult population is overweight. In the United States, several economists have connected ...
Federal regulations stipulate that food products be protected against physical, chemical and micr... more Federal regulations stipulate that food products be protected against physical, chemical and microbial contamination during transportation and holding. An expert opinion elicitation was conducted to assess food safety hazards and preventive controls associated with the transportation and holding of food commodities. Frequency and severity risk rankings suggest five food safety hazards of greatest concern across all modes of transport: (1) lack of security; (2) improper holding practices for food products awaiting shipment or inspection; (3) improper temperature control; (4) cross-contamination; and (5) improper loading practices, conditions, or equipment. Factor analysis suggests that "in-transit" and "organizational" risk factors might explain the relationships among the various food safety hazards. Raw seafood, raw meat and poultry, and refrigerated raw and ready-to-eat foods have the highest overall risk (in descending order) across all modes of transit. Our analysis also identified a range of preventive controls that may help eliminate/mitigate the risks to food during transport and storage, including: employee awareness and training, management review of records, and good communication between shipper, transporter and receiver.
Journal of Macromolecular Science, Part A, 2016
Environmental Microbiology, Mar 1, 2011
The near ubiquitous distribution of nifH genes in sediments sampled from 14 high-temperature (48.... more The near ubiquitous distribution of nifH genes in sediments sampled from 14 high-temperature (48.0-89.0°C) and acidic (pH 1.90-5.02) geothermal springs in Yellowstone National Park suggested a role for the biological reduction of dinitrogen (N 2) to ammonia (NH 3) (e.g. nitrogen fixation or diazotrophy) in these environments. nifH genes from these environments formed three unique phylotypes that were distantly related to acidiphilic, mesophilic diazotrophs. Acetylene reduction assays and 15 N2 tracer studies in microcosms containing sediments sampled from acidic and high-temperature environments where nifH genes were detected confirmed the potential for biological N 2 reduction in these environments. Rates of acetylene reduction by sedimentassociated populations were positively correlated with the concentration of NH 4 + , suggesting a potential relationship between NH 4 + consumption and N2 fixation activity. Amendment of microcosms with NH 4 + resulted in increased lag times in acetylene reduction assays. Manipulation of incubation temperature and pH in acetylene reduction assays indicated that diazotrophic populations are specifically adapted to local conditions. Incubation of sediments in the presence of a N 2 headspace yielded a highly enriched culture containing a single nifH phylotype. This phylotype was detected in all 14 geothermal spring sediments examined and its abundance ranged from~780 tõ 6800 copies (g dry weight sediment) -1 , suggesting that this organism may contribute N to the ecosystems. Collectively, these results for the first time demonstrate thermoacidiphilic N 2 fixation in the natural environment and extend the upper temperature for biological N 2 fixation in terrestrial systems.
Lpi Contributions, Apr 1, 2010
Structure of a key intermediate in H-cluster biosynthesis and [FeFe]-hydrogenase maturation revea... more Structure of a key intermediate in H-cluster biosynthesis and [FeFe]-hydrogenase maturation reveals unifying themes in complex biological Fe-S cluster biosynthesis.
BMC Biochemistry, 2015
Dual-specificity phosphatase-5 (DUSP5) plays a central role in vascular development and disease. ... more Dual-specificity phosphatase-5 (DUSP5) plays a central role in vascular development and disease. We present a p-nitrophenol phosphate (pNPP) based enzymatic assay to screen for inhibitors of the phosphatase domain of DUSP5. pNPP is a mimic of the phosphorylated tyrosine on the ERK2 substrate (pERK2) and binds the DUSP5 phosphatase domain with a Km of 7.6 ± 0.4 mM. Docking followed by inhibitor verification using the pNPP assay identified a series of polysulfonated aromatic inhibitors that occupy the DUSP5 active site in the region that is likely occupied by the dual-phosphorylated ERK2 substrate tripeptide (pThr-Glu-pTyr). Secondary assays were performed with full length DUSP5 with ERK2 as substrate. The most potent inhibitor has a naphthalene trisulfonate (NTS) core. A search for similar compounds in a drug database identified suramin, a dimerized form of NTS. While suramin appears to be a potent and competitive inhibitor (25 ± 5 μM), binding to the DUSP5 phosphatase domain more tightly than the monomeric ligands of which it is comprised, it also aggregates. Further ligand-based screening, based on a pharmacophore derived from the 7 Å separation of sulfonates on inhibitors and on sulfates present in the DUSP5 crystal structure, identified a disulfonated and phenolic naphthalene inhibitor (CSD (3) _2320) with IC50 of 33 μM that is similar to NTS and does not aggregate. The new DUSP5 inhibitors we identify in this study typically have sulfonates 7 Å apart, likely positioning them where the two phosphates of the substrate peptide (pThr-Glu-pTyr) bind, with one inhibitor also positioning a phenolic hydroxyl where the water nucleophile may reside. Polysulfonated aromatic compounds do not commonly appear in drugs and have a tendency to aggregate. One FDA-approved polysulfonated drug, suramin, inhibits DUSP5 and also aggregates. Docking and modeling studies presented herein identify polysulfonated aromatic inhibitors that do not aggregate, and provide insights to guide future design of mimics of the dual-phosphate loops of the ERK substrates for DUSPs.
Journal of bacteriology, 2010
The genetic context, phylogeny, and biochemistry of a gene flanking the H(2)-forming methylene-H(... more The genetic context, phylogeny, and biochemistry of a gene flanking the H(2)-forming methylene-H(4)-methanopterin dehydrogenase gene (hmdA), here designated hmdB, indicate that it is a new member of the radical S-adenosylmethionine enzyme superfamily. In contrast to the characteristic CX(3)CX(2)C or CX(2)CX(4)C motif defining this family, HmdB contains a unique CX(5)CX(2)C motif.
Nature, 2010
Figure 1 | Ball-and-stick representation of the H-cluster in [FeFe]hydrogenase from Clostridium p... more Figure 1 | Ball-and-stick representation of the H-cluster in [FeFe]hydrogenase from Clostridium pasteurianum 29 . The H-cluster is bound to the protein (tube representation) by four cysteine ligands of the [4Fe-4S]
Environmental Microbiology, 2011
The near ubiquitous distribution of nifH genes in sediments sampled from 14 high-temperature (48.... more The near ubiquitous distribution of nifH genes in sediments sampled from 14 high-temperature (48.0-89.0°C) and acidic (pH 1.90-5.02) geothermal springs in Yellowstone National Park suggested a role for the biological reduction of dinitrogen (N 2) to ammonia (NH 3) (e.g. nitrogen fixation or diazotrophy) in these environments. nifH genes from these environments formed three unique phylotypes that were distantly related to acidiphilic, mesophilic diazotrophs. Acetylene reduction assays and 15 N2 tracer studies in microcosms containing sediments sampled from acidic and high-temperature environments where nifH genes were detected confirmed the potential for biological N 2 reduction in these environments. Rates of acetylene reduction by sedimentassociated populations were positively correlated with the concentration of NH 4 + , suggesting a potential relationship between NH 4 + consumption and N2 fixation activity. Amendment of microcosms with NH 4 + resulted in increased lag times in acetylene reduction assays. Manipulation of incubation temperature and pH in acetylene reduction assays indicated that diazotrophic populations are specifically adapted to local conditions. Incubation of sediments in the presence of a N 2 headspace yielded a highly enriched culture containing a single nifH phylotype. This phylotype was detected in all 14 geothermal spring sediments examined and its abundance ranged from~780 tõ 6800 copies (g dry weight sediment) -1 , suggesting that this organism may contribute N to the ecosystems. Collectively, these results for the first time demonstrate thermoacidiphilic N 2 fixation in the natural environment and extend the upper temperature for biological N 2 fixation in terrestrial systems.
Applied and Environmental Microbiology, 2011
Subglacial sediments sampled from beneath Robertson Glacier (RG), Alberta, Canada, were shown to ... more Subglacial sediments sampled from beneath Robertson Glacier (RG), Alberta, Canada, were shown to harbor diverse assemblages of potential nitrifiers, nitrate reducers, and diazotrophs, as assessed by amoA, narG, and nifH gene biomarker diversity. Although archaeal amoA genes were detected, they were less abundant and less diverse than bacterial amoA, suggesting that bacteria are the predominant nitrifiers in RG sediments. Maximum nitrification and nitrate reduction rates in microcosms incubated at 4°C were 280 and 18.5 nmol of N per g of dry weight sediment per day, respectively, indicating the potential for these processes to occur in situ. Geochemical analyses of subglacial sediment pore waters and bulk subglacial meltwaters revealed low concentrations of inorganic and organic nitrogen compounds. These data, when coupled with a C/N atomic ratio of dissolved organic matter in subglacial pore waters of ϳ210, indicate that the sediment communities are N limited. This may reflect the combined biological activities of organic N mineralization, nitrification, and nitrate reduction. Despite evidence of N limitation and the detection of nifH, we were unable to detect biological nitrogen fixation activity in subglacial sediments. Collectively, the results presented here suggest a role for nitrification and nitrate reduction in sustaining microbial life in subglacial environments. Considering that ice currently covers 11% of the terrestrial landmass and has covered significantly greater portions of Earth at times in the past, the demonstration of nitrification and nitrate reduction in subglacial environments furthers our understanding of the potential for these environments to contribute to global biogeochemical cycles on glacial-interglacial timescales.
Applied and Environmental Microbiology, 2011
Previous research has shown that sequences of 16S rRNA genes and 16S-23S rRNA internal transcribe... more Previous research has shown that sequences of 16S rRNA genes and 16S-23S rRNA internal transcribed spacer regions may not have enough genetic resolution to define all ecologically distinct Synechococcus populations (ecotypes) inhabiting alkaline, siliceous hot spring microbial mats. To achieve higher molecular resolution, we studied sequence variation in three protein-encoding loci sampled by PCR from 60°C and 65°C sites in the Mushroom Spring mat (Yellowstone National Park, WY). Sequences were analyzed using the ecotype simulation (ES) and AdaptML algorithms to identify putative ecotypes. Between 4 and 14 times more putative ecotypes were predicted from variation in protein-encoding locus sequences than from variation in 16S rRNA and 16S-23S rRNA internal transcribed spacer sequences. The number of putative ecotypes predicted depended on the number of sequences sampled and the molecular resolution of the locus. Chao estimates of diversity indicated that few rare ecotypes were missed. Many ecotypes hypothesized by sequence analyses were different in their habitat specificities, suggesting different adaptations to temperature or other parameters that vary along the flow channel.
ABSTRACT Structure of a key intermediate in H-cluster biosynthesis and [FeFe]-hydrogenase maturat... more ABSTRACT Structure of a key intermediate in H-cluster biosynthesis and [FeFe]-hydrogenase maturation reveals unifying themes in complex biological Fe-S cluster biosynthesis.
Federal regulations stipulate that food products be protected against physical, chemical and micr... more Federal regulations stipulate that food products be protected against physical, chemical and microbial contamination during transportation and holding. An expert opinion elicitation was conducted to assess food safety hazards and preventive controls associated with the transportation and holding of food commodities. Frequency and severity risk rankings suggest five food safety hazards of greatest concern across all modes of transport: (1) lack of security; (2) improper holding practices for food products awaiting shipment or inspection;