Browsing by Author "Morley, Paul, committee member"
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Item Embargo A comprehensive study of Salmonella infections and microbial analysis of probiotics on beef cattle(Colorado State University. Libraries, 2023) Thompson, Tyler Warren, author; Nair, Mahesh Narayanan, advisor; Geornaras, Ifigenia, committee member; Belk, Keith, committee member; Noyes, Noelle, committee member; Morley, Paul, committee memberNon-typhoidal Salmonella remains a significant concern for food safety in the United States, causing millions of infections, hospitalizations, and deaths yearly. The Healthy People 2030 initiative set forth by the U.S. Department of Health and Human Services aims to address this issue by establishing goals and objectives for national health promotion and disease prevention, including two objectives focused on Salmonella control in the food supply. The recent declaration of Salmonella as an adulterant in certain poultry products by the U.S. Department of Agriculture further highlights the urgency of this issue. To align with the Healthy People 2030 goals and achieve a 25% reduction in salmonellosis, the U.S. Department of Agriculture's Food Safety and Inspection Service (FSIS) implemented new performance standards for beef products. However, such policies must be supported by quantitative microbial risk assessments (QMRA) to determine their impact on Salmonella infections. Therefore, these analyses would benefit from a systematic review examining existing literature on Salmonella, considering factors such as illness rates, exposure, and bacterial loads. This review included 42 articles that provided data necessary for fitting a dose-response model to empirical data that describes how dose, virulence group, and food vector affect illness (attack) rates. Results from the mixed-effects logistic regression model showed significant impacts of log dose consumed, virulence group, and food vector on illness rates. Notably, Salmonella serogroups of "Higher" virulence were found to be associated with greater odds of illness than "Lower" virulence strains. The study highlights the need for improved data reporting and standardized outbreak investigations to enhance the fitting of models to outbreak data. By considering factors like serovar group and food vector in the modeling process, regulators can demonstrate what influences attack rate to frame more effective food safety policies. In conclusion, this systematic review provides valuable insights into Salmonella infection risk from food sources and emphasizes the importance of evidence-based policies to reduce the burden of Salmonella-related illnesses and improve food safety in the United States. Liver abscesses in beef cattle are a common problem associated with highly-fermentable carbohydrate diets during finishing, leading to decreased production efficiency and aggregate carcass value. Dietary antimicrobial supplementation, such as tylosin, helps to control liver abscesses but raises concerns about selection for antimicrobial resistance. This study examined the impact of a probiotic mixture of propionic and lactic acid bacteria on microbial communities and antimicrobial resistance genes (ARGs) in fecal and liver abscess samples from beef cattle alongside Salmonella populations of mesenteric lymphatic tissues. Treatment diets fed in this study included a probiotic mixture alone (DFM), inclusion of Tylosin (TYL), a combination of including both (DFM+TYL), and a control group diet that did not include any supplements (CON). Fecal samples were collected at the time that feeding started, and then 28 d before arriving at the abattoir, where liver abscesses and mesenteric lymph nodes were sampled. Fecal and liver abscess samples were subjected to 16S rRNA and targeted enriched shotgun metagenomics to evaluate microbial communities and resistance genes of bacteria present. A portion of the liver abscess and mesenteric lymph nodes were tested for presence of Salmonella using PCR with further analysis of enumeration and serotype classification for mesenteric lymph nodes. Results showed no differences (P > 0.05) between the fecal microbiomes of the different treatment groups, and the addition of tylosin or probiotic mixture did not impact the fecal resistome. Similarly, no differences (P > 0.05) were observed between the liver abscess microbiomes of the different (P > 0.05) treatment groups, with Fusobacteria and Bacteroidetes being the dominant phyla in liver abscesses. Results indicated that incorporating DFMs did not affect Salmonella prevalence in the cattle's mesenteric lymph nodes or liver abscesses. Presence of Salmonella was found at low levels in only 22% of samples (91 positive out of 503 samples), just below 1 log CFU/g, and was predominantly represented by the C1 serogroup in mesenteric lymph nodes. These findings suggest that while diet interventions may not have a substantial impact, Salmonella can colonize mesenteric lymphatic tissues in cattle at low frequencies and concentrations. Treatment groups tested had no impact (P > 0.05) on fecal and liver abscesses microbiomes and resistance gene presence, along with no impact on Salmonella prevalence in liver abscesses or mesenteric lymphatic tissues.Item Open Access Characterization of the resistome and microbiome of retail meats processed from carcasses of conventionally and naturally raised cattle(Colorado State University. Libraries, 2019) Thomas, Kevin, author; Belk, Keith, advisor; Morley, Paul, committee member; Metcalf, Jessica, committee memberConcern over human exposure to antimicrobial resistance (AMR) via consumption of meat products has raised questions about use of antimicrobial drugs in food-animal production. This concern has led to an increase in consumer demand for meat products from naturally-raised cattle, or those raised without use of antimicrobials. While previous studies have assessed AMR gene presence in cattle and throughout the beef supply chain, very little work has surveyed the resistome on retail meats available for consumer purchase. The objective of this study was to determine the extent of antimicrobial resistance and characterize the microbiome in retail ground beef products from naturally-raised (raised without antibiotics) and conventionally-raised cattle utilizing 16S rRNA and targeted shotgun metagenomic, high-throughput sequencing techniques. Differing in packaging types and lean points, samples of ground beef derived from carcasses of cattle that were conventionally-raised (n = 50) or naturally-raised cattle (n = 50) were purchased from retail outlets in six major metropolitan cities throughout the United States. Samples were shipped to Colorado State University and processed following 48 hours of refrigeration at 4°C. Thirty-gram portions of each sample were removed and subjected to DNA extraction procedures via DNeasy PowerFecal Microbial Kit. Cell lysates were composited by production system and city before being subjected to paired-end 16S rRNA gene sequencing and targeted shotgun metagenomic sequencing using an enrichment system developed in our laboratory. Microbiome analysis was performed from 16S data with QIIME2 v.2018.4 by utilizing many of the available plugins. Resistome analysis of enriched metagenomic data was performed using a modified AMRPlusPlus pipeline. Microbiome alpha diversity analysis indicated that ground beef processed from conventionally-raised animals had a greater (P < 0.05) species richness than natural ground beef products. Microbiome composition differed (P < 0.05) between samples of differing production systems based on abundance weighted UniFrac distances. Additionally, when analyzed using unweighted UniFrac distances, microbial composition differed (P < 0.05) between samples from different cities. Differences in product packaging availability between cities may have caused these differences detected in microbiome composition, as well as environmental contamination or product handling in distribution. Targeted shotgun sequencing yielded a total of 4.6 trillion reads across all 60 composite samples, with only 58 samples containing hits to AMR. Of these 58 samples, 10.1 million reads were assigned to: 520 groups, 101 mechanisms of resistance, and 22 classes of antibiotics. The three most abundant classes of resistance detected included tetracyclines (56% of assigned reads), multi-drug resistance (21% of reads), and beta-lactams (7% of reads). An analysis of similarity on samples ordinated using Euclidian distances suggested that the overall resistome differed (P < 0.05) by production system, likely driven by greater antimicrobial resistance group variation among conventional retail samples. Results from this study profiled resistance and characterized microbial composition of retail beef products from two major production practices. While the results do not discredit concern over imprudent use of antibiotics in beef production, differing management techniques in cattle production do not appear to have a direct impact on the resistome or microbiome of final retail products available to consumers.Item Open Access Effects of antibiotic treatment strategies on feedlot cattle resistome and microbiome(Colorado State University. Libraries, 2016) Weinroth, Margaret, author; Belk, Keith, advisor; Morley, Paul, committee member; Martin, Jennifer, committee memberThe objective of this study was to evaluate resistome and microbiome changes in feedlot cattle exposed to commonly used antimicrobials. Sixteen pens of cattle (N=16) were randomly assigned to one of four antimicrobial treatments (n=4) resulting in a complete 2x2 factorial arrangement. The first factor was to treat Ceftiofur crystalline free acid (CCFA) to either the entire pen of animals (high dosage) or to one animal in the pen (low dosage). The second factor was the subsequent feeding of chlortetracycline (CTC) in feed to the entire pen of cattle or not administering CTC to a pen of cattle. Rectal fecal samples were collected from individual cattle within each pen on days 0 and 26. Deoxynucleic acid was extracted from individual fecal samples and pooled by DNA mass, so each pen had one composite sample on day 0 and day 26. Deoxynucleic acid was sequenced on an Illumina HiSeq 2000. Sequencing data (as known as reads) were aligned to a comprehensive antimicrobial resistance gene database and assigned to taxonomic labels. Sixty-eight antimicrobial resistance genes and 431 species were identified across all samples. Resistance to tetracycline was identified as the primary resistance at class level (66.9%) with resistance to Macrolide-lincosamide-streptogramin B (MLS) making up the majority of the remainder (26.2%). Resistance to tetracycline and aminoglycoside in the feces decreased (P < 0.05) in relative abundance from day 0 to day 26 when the cattle were fed CTC regardless of CCFA exposure. Beta-lactactams were the only class of resistance affected by the CCFA treatment, with low exposure CCFA pens exhibiting a smaller (P < 0.05) resistome on day 26 than those steers in high exposure CCFA pens, regardless of CTC treatment. These results indicate that the exposure to tetracycline for cattle may not be directly associated to the resistance to tetracycline in their feces. Further research is needed to explore more about this. Additionally, the decrease in resistance to aminoglycoside with no cattle exposed to anyaminoglycosides during the study raises the possibility of co-selection of resistant genes. Overall, the relative abundance of microbiome did not differ (P > 0.05) between pens of cattle with CCFA or CTC treatments but differed (P < 0.05) between day 0 and day 26. Overall microbiome relative abundance did not differ (P > 0.05) due to CCFA or CTC treatments but differed (P < 0.05) between day 0 and day 26. Changes in the microbiome over time affected all 19 phyla identified when all treatments were pooled together. It has been well established in humans that antimicrobial treatment changes in the microbiome (Khoruts et al., 2010; Preidis and Versalovic, 2009). While these findings are not as robust livestock, there is ongoing investigation establishing these same results that may lead to further understanding of how the microbiome of livestock responds to antibiotics.Item Open Access Efficacy of sulfuric acid sodium sulfate on inoculated populations of Salmonella spp. and Campylobacter spp. on pork subprimals, and its effects on natural spoilage microflora, lean discoloration and off-odors(Colorado State University. Libraries, 2016) McCullough, Kathryn Rose, author; Belk, Keith, advisor; Morley, Paul, committee member; Delmore, Robert, committee member; Yang, Hua, committee memberSalmonella and Campylobacter are pathogens commonly associated with foodborne illness. As these pathogens are often found in fresh pork, efforts to reduce or eliminate them is imperative to the pork industry. Additionally, fresh pork is highly perishable and maintenance of desirable attributes is imperative. So, extending shelf life of fresh pork is important to maintain profitability and desirability of product. Although a variety of attributes can determine pork shelf-life, reducing spoilage microflora is an important quality control point. Therefore, this study was conducted to determine efficacy of applying sulfuric acid sodium sulfate (SA) to reduce inoculated populations of Salmonella spp. and Campylobacter spp. on pork subprimals. Additionally, this study aimed to determine efficacy of SA application against inoculated populations of non-pathogenic Escherichia coli that could then serve as surrogates for Salmonella spp. and Campylobacter spp. on pork in in-plant trials (Experiment 1). This study also was conducted to determine effects of a SA spray on the natural spoilage microflora, off odor characteristics, and discoloration properties of pork subprimals during vacuum storage and simulated retail display (Experiment 2). And, SA was evaluated in a commercial pork in-plant system against the natural microflora and inoculated populations of a surrogate bacteria (Experiment 3). For Experiment 1, vacuum packaged pork subprimals were obtained from a local retailer less than 10 days postmortem. Entire subprimals were cut into uniform sample pieces and assigned to one of the following treatments: 1.0 pH SA, 1.5 pH SA, water or an untreated control. Samples were inoculated to a target level of 6 logs CFU/g for Salmonella spp. and surrogate E. coli, or 5.5 logs CFU/g for Campylobacter spp., with cocktails before treatment. Surviving pathogen and non-pathogenic E. coli populations were determined at 5 minutes post- treatment and at 24 h post-treatment. For Experiment 2, boneless pork loins and bone-in backribs were obtained from a commercial pork processing facility and treated with a topical spray of SA at 1.5 pH, 1.0 pH, or an untreated control. After treatment, all samples were placed in dark, refrigerated storage for 14 d or 21 d, after which one half of the samples were removed from storage, overwrapped with polyvinyl chloride film, and placed into retail display cases maintained at 4°C (±2°C) for up to 96 h. At 12 h intervals for the duration of simulated retail display, trained panelists evaluated percent discoloration. Additionally, at 0, 48 and 96 h of display, trained panelists evaluated intensity of off odors and plated and enumerated populations of Psychrotrophic, Pseudomonas, Lactic acid bacteria and yeast and molds. For Experiment 3, 60 carcasses were railed off and market strategically with 5 x 10 cm2 areas. Half the zones were inoculated with the surrogate bacteria, the other half remained uninocualted. Carcasses were then treated with the SA using a commercial application spray cabinet. For Experiment 1, application of 1.0 pH SA was the most effective (P < 0.05) at reducing inoculated populations of both Salmonella spp, and Campylobacter spp, compared to all other treatments. However, no difference (P > 0.05) was observed for Campylobacter and surrogate bacterial populations determined at 5 min versus populations at 24 h. Additionally, non-pathogenic E. coli strains were affected less by treatment than inoculated Salmonella spp. and Campylobacter spp.populations and can, therefore, effectively serve as surrogates for Salmonella spp. and Campylobacter spp. For Experiment 2, after 14 and 21 d of dark storage, both boneless loins and backribs sprayed with 1.0 pH SA had lower (P < 0.05) Psychrotrophic, Pseudomonas, Lactic acid bacteria and yeast and mold populations than control or 1.5-pH treated samples at 0, 48 and 96 h of display. Percent discoloration of boneless loin chops increased over the duration of retail display for products stored for 14 and 21 d before simulated retail display. Boneless loin chops treated with 1.0 pH SA had a greater percent discoloration at each simulated retail display test time than untreated chops or those sprayed with 1.5 pH SA. For Experiment 3, SA proved to effectively lower (P < 0.05) both inoculated and uninoculated bacterial (TPC, EB, TCC, and ECC) populations on pork carcasses. However, treatment with 1.0 pH SA was more effective than treatment with 1.3 pH SA.Item Open Access Epidemiological, physiological and genetic risk factors associated with congestive heart failure and mean pulmonary arterial pressure in cattle(Colorado State University. Libraries, 2014) Neary, Joseph Michael, author; Garry, Franklyn, advisor; Thomas, Milton, advisor; Orton, Christopher, committee member; Enns, Mark, committee member; Morley, Paul, committee member; Holt, Timothy, committee memberCongestive heart failure, secondary to pulmonary hypertension, has historically been considered a disease associated with high altitude exposure. The disease was first reported to occur at altitudes over 2,440 m (8,000 ft.) and so became known as "high altitude disease". One common clinical sign due to congestive heart failure in cattle is swelling of the brisket. Consequently, the disease also became known as "brisket disease". In more recent years, congestive heart failure has been reported to occur in both beef and dairy cattle at a more moderate altitude of 1,600 m. Anecdotal reports from cattle producers in Nebraska, Colorado and Texas suggest that the incidence of congestive heart failure may be increasing. This suggests that bovine congestive heart failure is not strictly a disease of high altitude exposure. Anatomical studies of cattle indicate that cattle have a smaller lung volume and alveolar surface area available for gas exchange than mammals with similar body masses and oxygen requirements. This may be because selection for increased growth rate, and other traits of high production, increases metabolic oxygen demand. The overarching hypothesis of this doctoral dissertation was that congestive heart failure secondary to pulmonary hypertension is not strictly a disease of high altitude but, a multifactorial disease, that is also associated with physiological traits that increase metabolic oxygen demand relative to oxygen supply via the cardiopulmonary system. The goal of this doctoral dissertation was to identify epidemiological, physiological and genetic risk factors associated with congestive heart failure and increased mean pulmonary arterial pressure in cattle. The results of this dissertation indicate that pulmonary arterial pressures of cattle are substantially higher than other mammalian species. Among pre-weaned calves, mean pulmonary arterial pressures increased significantly with age even at the moderate altitude of 1,470 m. As hypothesized, high oxygen demand relative to supply was positively associated with mean pulmonary arterial pressure in both pre-weaned calves at high altitude (2,170 m) and feedlot cattle at moderate altitudes (1,300 m). A study of 10 Canadian feedlots indicated that the risk of congestive heart failure increased from the year 2000 to the year 2012. The risk of congestive heart failure increased more than the underlying change in the risk of digestive disorders. Death from congestive heart failure occurred throughout the feeding period but typically occurred late in the feeding period, which makes this disease particularly costly to the feedlot industry. Treatment for respiratory disease was a significant risk factor for CHF. Increased growth rate and increased feed efficiency were risk factors for increased mean pulmonary arterial pressure in cattle. Mean pulmonary arterial pressures were significantly higher at the end of the confined feeding period at moderate altitude (1,300 m) than in pre-weaned calves at high altitude (2,170 m). Growth promotion through a steroid implant containing estradiol and trenbolone acetate did not significantly increase mean pulmonary arterial pressure as hypothesized. However, diastolic pulmonary arterial pressure was significantly lower than non-implanted controls, which suggests that one or both of these steroid hormones has cardio-pulmonary protective effects. Genome-wide association analyses of mean pulmonary arterial pressure and traits physiologically associated with mean pulmonary arterial pressures among calves at 4 and 6 months of age did not identify any concordant single nucleotide polymorphisms (SNPs). However, multiple SNPs were identified to be associated with mean and systolic pulmonary arterial pressures that have been associated with pulmonary hypertension in humans or have a plausible biological role in the development of pulmonary hypertension. In conclusion, the results of these investigations provide evidence to suggest that congestive heart failure of cattle is a multifactorial disease that is exacerbated by high altitude exposure.Item Open Access Evaluation and resolution of two sampling methods for airborne aromatic diisocyanate monomers(Colorado State University. Libraries, 2013) Schaeffer, Joshua W., author; Brazile, William, advisor; Reynolds, Stephen, committee member; Sandfort, Delvin, committee member; Hanneman, William, committee member; Morley, Paul, committee memberTo view the abstract, please see the full text of the document.Item Open Access Impact of antibiotic use on resistance in beef feedlot and dairy cattle(Colorado State University. Libraries, 2017) Rovira Sanz, Pablo, author; Belk, Keith, advisor; Morley, Paul, committee member; Schmidt, John, committee member; Yang, Hua, committee memberIn recent years, consumer demand for natural and organic foods has increased, partly due to concerns about the use of antimicrobials in food producing animals. The aim of this study was to evaluate antimicrobial resistance (AMR) in beef feedlot and dairy cattle raised without use of antibiotics compared to cattle raised in conventional (CONV) production. Three research projects were conducted to accomplish that general goal. In the first study, a conventional feedlot, natural feedlot, conventional dairy and organic dairy were visited to collect cattle feces, wastewater from lagoons and soil where the wastewater was applied. After DNA extraction, sequencing, and processing, metagenomic reads were aligned to reference databases for identification of antibiotic resistance genes (ARGs; i.e. the resistome) and bacteria (microbiome). Resistome composition was influenced by rearing method, cattle type, and type of sample. Most mechanisms of resistance affected by rearing method were enriched (P < 0.05) in conventional samples. Resistome differences were greatest for wastewater samples by rearing method but with contradictory results that suggested an impact of effluent management on wastewater resistome. Resistance to tetracycline and macrolide-lincosamide-streptogramin classes were more abundant in feces of feedlot cattle than in dairy cattle (P < 0.05); whereas resistance to beta-lactams was greatest in feces of dairy cattle (P < 0.05). Resistome and microbiome of feces differed (P < 0.05) between wastewater and soil samples. Results indicated that ARGs are widespread in beef feedlot and dairy cattle farms even in those with restricted antibiotic use. In the second study, feces from RWA (n=36) and CONV (n=36) cattle lots were recovered from colons at a commercial beef processing plant. Samples were equally distributed by month and production protocol over one year (3 samples/production protocol/month). After extracting DNA from individual samples, composite samples were prepared by mixing DNA from each lot into a single composite sample (N = 72) and sequencing the composites on an Illumina platform. Metagenomic reads were processed similarly to those in experiment 1for identification of ARGs and bacteria. Resistomes of CONV and RWA cattle were significantly different by season. In general, mechanisms conferring resistance to beta-lactams, tetracyclines, multi-drug and macrolides were more prevalent (P < 0.05) in feces from CONV colons than in RWA colons. In the third study, a systematic review and meta-analysis was performed to assess the relationship between antimicrobial use (AMU) and antimicrobial resistance (AMR) in feedlot cattle. After conducting a literature search and screening reported studies, 32 studies were selected for use that addressed AMR in Escherichia coli, Enterococcus, Salmonella, Campylobacter, and Mannheimia haemolytica. Overall, 60% (95% CI: 26% to 88%) of the observational studies and 50% (95% CI: 30% to 70%) of the controlled trials reported a positive association between AMU and AMR. Meta-analysis provided evidence for an increase in average relative risk (RR) associated with antibiotic use. Isolates recovered from treated cattle were 2.5 times (95% confidence interval: 1.7 – 3.5) as likely to display antibiotic resistance compared to isolates recovered from unexposed animals. Risk of resistance increases with animal defined daily doses (DDDs). More comprehensive studies that consider the relationship between antibiotic use in cattle and antibiotic resistant bacteria in humans are needed as a part of a farm to fork approach to tackle antimicrobial resistance.Item Open Access National Beef Quality Audit 2016 face to face interviews and validation of HPP pathogen destruction for use in raw pet food(Colorado State University. Libraries, 2017) Hasty, Joshua D., author; Woerner, Dale, advisor; Belk, Keith, advisor; Martin, Jennifer, committee member; Morley, Paul, committee member; Delmore, Robert, committee memberThe two studies described in this dissertation (1) were The National Beef Quality Audit (NBQA) and (2) the Validation of HPP Pathogen Destruction for Use in Raw Pet Food. The NBQA is conducted every five years; the 2016 version face-to-face interviews gauged the status and progress of the live cattle production industry in improving overall quality and consistency of beef using the procedures of set forth in NBQA 2011.This was the first time that the audit of fed steers and heifers was combined with an audit of market cow and bull beef. Face-to-face interviews were designed to illicit definitions for beef quality, estimate willingness to pay (WTP) for quality attributes, establish relative importance (RI) rankings for important quality factors, and assess images, strengths, weaknesses, potential threats, (SWOT) and shifting trends in the beef industry since the 2011 audit. Individuals making purchasing decisions in five market sectors of the steer/heifer and cow/bull beef supply chain were interviewed, including packers (n = 36), retailers (including large and small supermarket companies and warehouse food sales companies; n = 35), food service operators (including quick-serve, full-service, and institutional establishments; n = 29), further processors (n = 64), and peripherally related government and trade organizations (GTO; n = 30). Face-to-face interviews were conducted across the U.S. between January and November of 2016 using a designed (by sequence) dynamic routing program designed on the Qualtrics software platform (Qualtrics 2016; Provo, UT, USA). Interviewers from three separate land-grant universities first correlated on the administration of interviews in November of 2015 to standardize data collection. Definitions (as described by interviewees) for the seven pre-determined quality factors, including: (1) How and where the cattle were raised, (2) Lean, fat, and bone, (3) Weight and size, (4) Visual characteristics, (5) Food safety, (6) Eating satisfaction, and (7) Cattle genetics were recorded verbatim and categorized into similar responses for analysis. It was critical to understand how interviewees perceived the meaning of each of the seven quality factor groupings to interpret WTP and RI responses. As in NBQA-2011, "food safety" was the most important (P < 0.05) quality factor in RI scaling. Additionally, each sector that did not list "food safety" as a non-negotiable must have characteristic, but was willing to pay a premium for the trait, said that they would pay an average of 11.1% premium for a guarantee of their definition of "food safety" (likely overinflated). The "eating satisfaction" quality factor, primarily defined as "customer satisfaction" by all sectors, was ranked second (P < 0.05) by all marketing sectors except packers, who ranked "lean, fat, and bone" second. Compared to NBQA-2011, generally, a higher percentage of companies were willing to pay a premium for guaranteed quality attributes, but overall were willing to pay lower average premiums than the companies interviewed in 2011. In the second part of this study, (2) non-pathogenic E. coli (ATCC BAA 1427-31), were used to validate the efficacy of High Pressure Processing (HPP) as a destruction tool for use in raw pet food. According to the American Pet Products Association (APPA), pet industry expenditures in the U.S. have grown more than 350% in the past 20 years. Monetarily, annual expenditures increased by approximately $2 billion dollars each year for the past 5 years. Furthermore, APPA estimates that 2016 U.S. pet industry expenditures will exceed $62 billion dollars. Raw pet food products are a rapidly growing sector of the pet food industry. While these formulations are increasingly attractive to pet owners, food safety has historically been a concern. This concern, met with FDA regulations of "zero tolerance" for Salmonella, demands that raw pet food producers explore technologies for the elimination of pathogens in raw pet food products. Thus, the objective of this second experiment was to evaluate the effects of HPP and frozen storage on the destruction of surrogate pathogens in a raw pet food. Approximately 18 kg of a raw beef pet food was inoculated to a target of 7 logs CFU/g with a 5 strain cocktail of non-pathogenic Escherichia coli (ATCC BAA 1427-31), which previously were validated as surrogates for STECs and Salmonella (Dickson, 2015). Inoculated product was packaged in 227 g individual roll-stock packages and shipped to a commercial HPP facility for HPP application. Inoculated samples were subjected to HPP at 87,000 psi for 480 seconds. After HPP processing, samples were transported on ice to Colorado State University for determination of remaining bacterial populations. Samples were assigned randomly to either a 24-hours post-processing (n = 10) or following 5-d of frozen storage at -23˚C (n = 10) evaluation times. Raw product samples were serially diluted in BPW and plated onto selective (Violet Red Bile Agar; VRBA; selective for coliforms) and non-selective (Tryptic Soy Agar; TSA) medias for enumeration. The TSA survivors totaled 5.36 and 4.6 log CFU/g 24 hours post-HPP and post-frozen storage, respectively. Data were analyzed using the mixed procedure of SAS (version 9.3; Cary, NC) and separated using the PDIFF statement with an α of 0.05. These data suggested that HPP is an effective tool for destruction of foodborne pathogens in raw pet food diets, but that HPP alone is not sufficient to reduce pathogenic loads beyond detection limits. Additionally, these data suggest that a frozen storage period following HPP may also be an effective method for enhancing pathogen destruction. Additional research related to the safety of raw pet food is needed.Item Open Access Use of the health belief model to explain perceptions of zoonotic disease risk by animal owners(Colorado State University. Libraries, 2011) Wheeler, Karen L., author; Trumbo, Craig, advisor; O'Keefe, Garrett, committee member; Morley, Paul, committee memberThe rise in the number of public health risks from zoonotic disease in just the past two decades has underscored both the importance of educating the public about risky health behaviors and preventive measures, and the need to communicate these topics in clear, concise and accessible language without inciting fear. People love their animals, typically sharing physical gestures of affection similar to those exchanged between humans. Most pet owners are poorly informed about risks posed by infectious agents that can be shared between animals and humans, and which pose a public health risk. To effectively communicate this information, we must first understand the determinants of a particular behavior: the role of beliefs, perception of risk, benefits, and barriers to change. The Health Belief Model, a theory that incorporates each of these factors, allows researchers to assess what might constitute a cue to action for individuals to make recommended changes in preventive health behavior. For this study examining the knowledge and perceptions of zoonotic disease risk and information-seeking behavior amongst small and mixed animal owners in the Inter-Mountain West, one thousand names were randomly selected from the client lists of the James L. Voss Veterinary Teaching Hospital at Colorado State University. Four hundred participants (40 percent) responded to a mailed, self-administered, anonymous survey. Descriptive analysis assessed awareness of two zoonotic diseases: Salmonella and Methicillin-resistant Staphylococcus aureus; and information-seeking behaviors related to animal health and disease risk. Analysis revealed that, adopting protective behaviors is best achieved by perceiving greater benefits to adopting the recommended behavior, perceiving fewer barriers, and receiving more cues to action. Results also found differences between small and mixed animal owners in several areas of inquiry, including knowledge of disease, perception of risk, perception of cues to action and in information-seeking behaviors.Item Open Access Using the dog as a model to investigate environmental and genetic risk factors for mature, antigen-driven lymphoproliferative disorders(Colorado State University. Libraries, 2017) Labadie, Julia, author; Magzamen, Sheryl, advisor; Avery, Anne, advisor; Anderson, Brooke, committee member; Feigelson, Heather, committee member; Morley, Paul, committee member; Page, Rodney, committee memberTo view the abstract, please see the full text of the document.