Browsing by Author "Martin, Jennifer, advisor"

Now showing 1 - 4 of 4

Open Access
Effects of potential Tylosin substitutes on Salmonella prevalence and the microbiome of subiliac lymph nodes of beef feedlot cattle
(Colorado State University. Libraries, 2017) Holzer, Katlyn, author; Martin, Jennifer, advisor; Belk, Keith, committee member; Metcalf, Jessica, committee member; Schountz, Tony, committee member
Tylosin, a macrolide antibiotic, is fed to feedlot cattle for liver abscess prevention. Tylosin alternatives are currently being investigated as pressures to reduce the amount of antibiotics used in livestock increase. Understanding effects of various feeding strategies on the safety of beef products is a priority as alternatives are investigated. This study investigated the effect of Tylosin, and two Tylosin alternatives on the prevalence of Salmonella in subiliac lymph nodes (SLN) and the microbiome of SLN from feedlot cattle. Salmonella harborage in the lymph node is a challenge for the beef industry as ground beef is made from beef trimmings that commonly contain lymph nodes. Consumption of contaminated ground beef is one of the possible foodborne routes of Salmonella infection. SLN (n=600) were collected from feedlot cattle (n = 5,481) at the time of slaughter. Overall 84.6% of the SLN were positive for Salmonella and the treatment did not influence prevalence (P > 0.8402). Samples from each pen of feedlot cattle (15 SLN/pen) were composited for microbiome analysis using 16s rRNA amplicon sequencing. Samples were analyzed using the open-source software Quantitative Insights Into Microbial Ecology (QIIME). The treatment did not influence the microbiome of the SLN (P = 0.223; P= 0.267). The top three phyla present were Proteobacteria (67.3%), Actinobacteria (10.2%), and Acidobacteria (9.5%). Although Salmonella was culturally isolated, it was not identified in the microbiome analysis because the genus could not be resolved for 18.9% of the Enterobacteriaceae family. Understanding why Salmonella is detectable in the lymph nodes may hold the key for prevention, and characterizing the microbiome is crucial for this process.
Open Access
Ground beef pathogen dynamics and the current scope of the impact of foreign materials on meat and pet food products
(Colorado State University. Libraries, 2023) Carlson, Chloé M., author; Martin, Jennifer, advisor; Engle, Terry, committee member; Delmore, Lynn, committee member; Webb, Colleen, committee member
This thesis provides an overview of ground beef consumption and the state of microbial testing of ground beef. The study focuses on understanding dynamic growth relationships between pathogenic and non-pathogenic bacteria in ground beef and how this information might be used to predict the presence of pathogens or the onset of microbial spoilage. Additionally, this thesis examines current United States Department of Agriculture Food Safety Inspection Service (USDA-FSIS) and the Food and Drug Administration (FDA) regulations around foreign material adulterated meat and pet food. The review looks at the challenges between the two regulatory bodies and provides guidance for improvement.
Open Access
Strategies to maintain market access for pork and enhance functionality of beef proteins
(Colorado State University. Libraries, 2023) Cochran, Hannah, author; Martin, Jennifer, advisor; Bosco-Lauth, Angela, committee member; Garry, Franklyn, committee member; Roman-Muniz, Noa, committee member
African swine fever is a high-consequence foreign animal disease endemic to sub-Saharan Africa and the island of Sardinia. The U.S. is the world's third largest pork producer, and ASF introduction would severely disrupt the pork supply chain, emphasizing a need to protect market access for U.S. proteins. However, niche producers raising swine intended for exhibition may not follow stringent biosecurity protocols and livestock show circuits may promote untracked animal movement across the country, potentially exacerbating virus spread in the event of ASF incursion into the U.S. Two Qualtrics surveys designed to evaluate knowledge, understanding, and perceptions of ASF and biosecurity principles of youth swine exhibitors and adults involved in the exhibition swine industry were distributed via flyers, emails, and canvassing at livestock shows. Youth exhibitors (age 21 and under) answered questions assessing their knowledge and provided basic demographic information, including their home state and states to which they traveled for exhibitions. Adult respondents answered the same questions assessing their knowledge and provided information on their time involved in the swine industry and number of shows attended by the youth they advise (if any). Youth respondents (n = 127) lived in 14 states and exhibited in 23 states, with 35% and 28% holding membership in state and national swine organizations, respectively. When provided with a list of ASF clinical signs, 34 individuals (26.9%) correctly identified all symptoms. Twenty-nine individuals (23%) incorrectly responded that ASF has been found in the U.S., and ten (7.9%) believed the virus cannot spread between pigs. Increased biosecurity understanding in youth exhibitors showed a significant relationship with an increase in years involved (p<0.05). Adult respondents (n = 211) had been involved in the swine industry for an average of 21 years, and the youth they advised attended 14 exhibitions in an average year. Nearly all adults (90.5%) identified direct contact with infected animals as a method of ASF transmission, while far fewer (36.39%) identified animal feed as a possible mechanism of transmission. These responses indicate highly varied knowledge of symptoms, routes of transmission, and biosecurity recommendations. Youth membership in state or national swine organizations offers a route for outreach and educational activities to enhance foreign animal disease preparedness, and adult presence at swine exhibitions allows for a wide variety of programming for all ages to better serve all levels of understanding. Fluctuations in the beef supply chain due to COVID-19 triggered discussions on methods to fully utilize edible proteins from beef carcasses, such as collagen. One potential method is the addition of collagen powder to beef frankfurters to replace a fraction of lean grind. The inclusion of NOVAPRO® collagen powder to beef franks at three hydration levels resulted in no significant differences (p>0.05) in water activity, pH, or shear force values between the treatment groups. Additionally, trained sensory panelists did not discern differences between treatment or control samples when asked to rate attributes that included beef flavor intensity, seasoning intensity, springiness, and mouth coating, indicating that NOVAPRO® powder could be added to processed meat products to reduce costs without compromising product quality.
Open Access
The effect of tylosin exposure or exclusion on liver abscess prevalence, fecal pathogen populations, and the microflora of finished beef products from feedlot cattle
(Colorado State University. Libraries, 2018) Weissend, Carla Jane, author; Martin, Jennifer, advisor; Belk, Keith, committee member; Bryant, Tony, committee member; Metcalf, Jessica, committee member; Weir, Tiffany, committee member
There is great pressure to reduce use of, and find alternatives to, antibiotics in animal production. More than 70% of feedlot cattle in 1000+ head lots are currently exposed to tylosin phosphate, a macrolide antibiotic used for the reduction and prevention of liver abscesses. As such, its potential removal from cattle feeding strategies could have a marked impact on both the economics of the beef industry and food safety. Additionally, little is known about the effect of tylosin exposure or exclusion on the microbiome of finished beef products. In light of these facts, a blinded, randomized, controlled field trial was conducted to evaluate the impact on the prevalence of liver abscesses and the characterization of the microbiome of feces, liver abscesses, carcasses, and finished beef products through 16S rRNA gene sequencing and shotgun sequencing from feedlot cattle with and without exposure to tylosin. Overall, liver abscess rates were lower among cattle exposed to tylosin. However, there were no differences among treatment groups for any of the sample types, suggesting that removal of tylosin from current feeding strategies will not upend the safety of the beef supply. The information gained in this study will provide valuable insight as the search for alternative feeding strategies to antibiotics continues.