The acquired ability of Salmonella to express varying morphotypes when placed in nutrient-limited conditions is hypothesized to predict increased resistance to food processing interventions. Two of the morphotypes expressed by Salmonella are Red, Dry and Rough (RDAR) and Smooth and White (SAW). Increased resistance is predicted for the RDAR morphotype...
This study aimed to determine the efficacy of baking to reduce bacterial populations (an unknown contaminant or Salmonella) in cookie dough. Baking conditions (time and temperature parameters) were selected based on conditions commonly used in industry. The first study (Chapter 2), “Baking as Validation for Control of Coliform Counts in...
Pasteurization is an effective method of reducing risks associated with foodborne pathogens in raw milk. Cheese made from raw milk has a higher potential to harbor harmful bacterial pathogens. However, some cheesemakers prefer to use unpasteurized milk to preserve the natural microflora present in the raw milk and to prevent...
The production of Cheddar cheese is a complex process with multiple potential sources of undesirable bacteria, including those that have negative impacts on product quality (spoilage organisms) and those that are used to evaluate sanitary conditions in the production environment (indicator organisms). The dairy industry commonly uses coliform bacteria as...
The acquired ability of Salmonella to express varying morphotypes when placed in nutrient-limited conditions is hypothesized to predict increased resistance to food processing interventions. Two of the morphotypes expressed by Salmonella are Red, Dry and Rough (RDAR) and Smooth and White (SAW). Increased resistance is predicted for the RDAR morphotype...
Full Text:
blanching treatment
Selena Callahan1*, JoyWaite-Cusic2
1Department of Microbiology, Oregon State University
The acquired ability of Salmonella to express varying morphotypes when placed in nutrient-limited conditions is hypothesized to predict increased resistance to food processing interventions. Two of the morphotypes expressed by Salmonella are Red, Dry and Rough (RDAR) and Smooth and White (SAW). Increased resistance is predicted for the RDAR morphotype...
Full Text:
to a steam blanching treatment
Selena Callahan1*, JoyWaite-Cusic2
1Department of Microbiology
Rework is a common practice in the dairy industry as a way for processors to minimize waste while recovering costs for dairy products that are unsaleable. The regulations available for reworking fluid dairy products only outline product eligibility requirements with a focus on repasteurization of the products containing rework as...
Foodborne outbreaks involving fresh produce have been on the rise since the late 1990's. Pathogens such as Salmonella spp. and Escherichia coli are prevalent in agricultural environments and commonly travel between farms via irrigation water. The Food Safety Modernization Act (FSMA) has placed an increased emphasis on microbiological standards of...
2020 and 2021 brought the first reported outbreaks of salmonellosis epidemiologically linked to dry bulb onions in the United States. Outbreak investigations were not able to implicate a specific source of the contamination but speculated that contaminated water was a significant contributor. The Produce Safety Rule established minimum standards for...
Multiple outbreaks of foodborne illness (Salmonella and E. coli O157:H7) have been associated with tree nuts and tree nut products since the early 2000s. In response to these outbreaks and many others in fresh produce and peanut butter, Congress created and passed the Food Safety Modernization Act (FSMA) to require...
Reports of foodborne outbreaks have increased in the last decade, posing a public health risk to consumers. In an attempt to mitigate this risk, the newly established Food Safety and Modernization Act (FSMA) takes a preventive rather than reactive approach to food safety. Under FSMA, producers are required to validate...
Salmonella is a bacterium responsible for several illnesses, including typhoid fever,
paratyphoid fever, and salmonellosis. It is commonly found in animal products, including
poultry. Determination of potential reservoirs of Salmonella contamination is important
to mitigate the risk of transmission and possible outbreaks. Outbreaks can negatively
impact the livelihood of local...
Butter has long been the premium choice for producing pastries such as Danish and croissants. Its inclusion has consistently delivered characteristically light and airy crumbs with beautifully flaky crust. Once considered a delicacy, pastries have now become innocuous in our everyday lives. Once requiring a skillful hand to sculpt and...
Flavored milk is a growing category for dairy products; however, it is a perishable product that is subject to microbial spoilage which can lead to a negative consumer experience and lead to lost sales. Flavored milk processors communicated unique spoilage events related to their products, including color loss of strawberry...
Vibrio parahaemolyticus infections in the United Stated have been linked to consumption of raw shellfish, particularly oysters, with symptoms of headache, abdominal pain, nausea, diarrhea, vomiting. Depuration, as a post-harvest process, has a long history of being applied in shellfish industry to reduce sewage bacteria. In order to reduce the...
United States Department of Agriculture-Food Safety and Inspection Service (USDA-FSIS) guidelines for beef jerky processing support producers' ability to satisfy the performance standard requirements for achieving a 5-log reduction in Salmonella and E. coli O157:H7. The first compliance guide for jerky processors was created in response to several Salmonella outbreaks...
The dairy industry has indicated that milk hauling sporadically compromises milk quality, but often the reason is unknown. Milk hauling practices are an underexplored area of research, and are in need of attention because during hauling milk is most exposed to the external environment in comparison with any other step...
Bloomy rind cheeses, including Camembert and Brie type cheeses, are highly susceptible to contamination by environmental pathogens during their manufacture and ripening. These cheeses undergo many physiochemical changes during ripening that provides these pathogens with a suitable environment to grow. One example of this change is an increase of pH...
Non-starter lactic acid bacteria (NSLAB) are found at low levels in fresh raw milk and are important to the dairy industry because of their potential impact on the flavor and texture of yogurt, sour cream, and cheese. The purpose of this study was to evaluate three methods for the identification...
Foodborne illness in the United States continues to be a complex and recurring issue despite our increased understanding of the pathogenic microorganisms responsible. Foodborne illness outbreaks and product recalls linked to pathogenic bacteria have been more frequent in the produce industry (e.g. fruits and vegetables) in the last ten years....
Listeria monocytogenes is the third most deadly foodborne pathogen in the United States. The young and elderly, as well as pregnant and immunocompromised people are the population most susceptible to serious illness and death from listeriosis infections.
Unlike most foodborne pathogens, L. monocytogenes does not live a solely enteric lifestyle....
Listeria monocytogenes contamination continues to pose challenges for the food industry and there is demand for effective methods of food preservation and protection that can also be considered clean label. A promising source of antilisterial compounds may be sourced from bacteria that produce novel byproducts. Ribosomally synthesized and post-translationally modified...
Given the many significant roles that bacteria play in modern food manufacturing, it is crucial that we have a fundamental understanding of how bacterial communities assemble and behave in the food manufacturing environment. The focus of this dissertation was to investigate both the spatial and temporal distributions of microbial communities...
Vibrio parahaemolyticus infections in the United States have been linked to consumption of raw oysters. Depuration has the potential to reduce contamination in live oysters after harvest. This study investigated the impact of depuration flow rate to reduce V. parahaemolyticus in raw oysters. Pacific oysters (n = 35 per trial)...
Bloomy rind cheeses, including Camembert and related varieties, can he produced using alternative processes that vary based on milk preacidification, cutting, curd handling, and ripening parameters. Modification of these parameters creates distinct cheeses such as lactic curd, stabilized curd, and hybrids of the two. The objective of this study was...
While breast milk is considered the best nourishment for newborns, they have a lowered ability to digest the fat rich liquid due to decreased lipase secretion for the first few months after birth. To offset this, breast milk itself contains Bile Salt-Stimulated Lipase (BSSL) which significantly heightens fat digestion ability....
Tree nuts have been implicated in a number of foodborne outbreaks and recalls in recent years linked to enteric pathogens, particularly Salmonella. Therefore, prior to distribution and marketing, it is necessary to understand the biological risks associated with the consumption of tree nuts and to find effective methods to inactivate...
Wine has recently been shown to be a possible protective agent against
microbial foodbome illness. The chemical environment of wine makes it difficult, if
not impossible, for microorganisms to survive. The low pH, high concentration of
organic acids, relatively high ethanol concentrations, and the potential for high levels
of sulfur...
Cheese has been produced since ancient times and continues to be an important nutrient-dense staple in many diets around the world. Cheese quality is of high importance to consumers, and it is important for cheese producers to establish process controls to prevent and control cheese spoilage. Fungal spoilage is of...
Hauling is a critical part of the commercial milk supply chain, yet very few studies have aimed to understand its impact on raw milk quality. Consolidation of the American milk industry has led to the use of tanker trucks for up to 24 h between cleanings, which is the maximum...
Wastewater treatment plants are considered one of the main sources and reservoirs of antimicrobial resistance (AMR). This study investigated the prevalence of 8 different phenotypes of AMR, multi-drug resistant (MDR), and extended-spectrum beta-lactamases (ESBL) producing E. coli in 17 wastewater treatment plants across Oregon in winter and summer of 2019...
Kappa-casein glycomacropeptide (CMP), a 64-amino-acid peptide, is released from kappa-casein after rennet treatment and is one of the major peptides in whey protein isolate (WPI). CMP has anti-inflammatory and antibacterial activities. CMP has two major amino acid sequences with different modifications including glycosylation, phosphorylation and oxidation. However, no previous work...
C. perfringens type A isolates are the causative agents of C. perfringens type A food poisoning (FP) and non-food-borne (NFB) human gastrointestinal diseases. In this study, we evaluated the antimicrobial effect of essential oil constituents (cinnamaldehyde, eugenol, allyl isothiocyanate (AITC), and carvacrol) against C. perfringens FP and NFB isolates grown...
The concept of terroir is commonly used as marketing tool to highlight unique characteristics of regional food products, however there is little scientific evidence of terroir pertaining to cheese. The purpose of this research was to investigate the potential impact of milk origin, pasteurization, and commingling on the sensorial, chemical,...
Whey protein isolate (WPI) and glycomacropeptide (GMP) have shown potential immunomodulatory properties. In this study, we investigated their effects on pro-inflammatory cytokine secretion using both in vitro and in vivo models. In LPS-stimulated THP-1-derived macrophages, digested WPI and GMP reduced cytokine expression, while whole GMP increased secretion. The in human...
Background: Alcohol is a nonessential nutrient widely consumed throughout the world. Chronic alcohol abuse is associated with numerous adverse skeletal effects. However, prior to this study, the effects of alcohol abuse on intracortical bone remodeling in an animal model had not been investigated. Reduced intracortical bone remodeling could impair repair...
It is estimated that for every 1 kg of cheese produced, approximately 9 kg of whey is created. For smaller producers something needs to be done to keep it out of water ways and potentially to valorize it. However, access to efficient secondary whey processing to isolate protein and lactose...
Objective: To describe associations between self-reported general health status, chronic conditions, and use of supplements containing botanicals (SCB) and describe reasons for use among U.S. adult supplement users.
Design: Cross-sectional analysis using data from the 2009-2014 National Health and Nutrition Examination Survey (NHANES). Information on self-reported dietary supplement use and...
Staphylococcus aureus is a human pathogen capable of producing enterotoxins causing staphylococcal food poisoning, one of the most economically important foodborne diseases in the U.S. This pathogen may be introduced to pre-cooked tuna meat used for the production of canned tuna because significant manual handling occurs after cooking of the...
Vibrio parahaemolyticus is the leading cause of foodborne illnesses associated with seafood consumption. Consuming raw or undercooked seafood contaminated with V. parahaemolyticus can result in development of acute gastroenteritis with symptoms of nausea, vomiting, abdominal cramping and watery diarrhea within 24 hours of infection. Illness is usually self-limited and lasts...
Whey protein is a functional food comprised of numerous bioactive peptides and proteins, including glycomacropeptide (GMP), a hydrophilic casein peptide that separates with the whey fraction during cheesemaking. GMP has a unique amino acid composition, making it a viable nutritional therapy in disorders where certain amino acids are implicated, while...
The reduction in mechanical load imparted on the body during spaceflight presents unique physiological challenges. One detrimental and seemingly unavoidable response to microgravity is rapid bone loss. This adaptation is hazardous not only to astronaut health, but to the success of long-duration exploration-class missions. Skeletal adaptation to spaceflight in astronauts...
The consumption of seafood in the United States has increased rapidly in recent years due to high quality protein and health benefits of seafood. Seafood can be a carrier for bacteria normally distributed in the marine environment and, in some cases, can be contaminated by human pathogens. Therefore, there is...
Whey protein’s potential for bioactivity is well documented, but there is disagreement on the extent to which it may modulate the immune system towards decreased inflammation. Decreased inflammation is generally perceived as a beneficial bioactivity in foods as excessive chronic inflammation is linked to morbidity and mortality.
This thesis first...
Corals provide a diversity of ecosystem services, are among the most biologically diverse ecosystems on Earth, and directly support ~500 million people globally; however, corals are increasingly experiencing significant threats and are undergoing severe bleaching events as the result of the warming climate. Using a two-year data set surrounding a...
Approximately ninety percent of urban Vietnamese households are connected to septic tanks, from which up to three-quarters of the sludge is reported to be dumped into waterways in residential areas. Vietnam has a considerable prevalence of antibiotic misuse and resultant antibiotic-resistant bacteria (ARB) in the human microbiome. Due to the...
Metabolic improvements and changes in gene expression were measured in mice fed polyphenol-rich extracts derived from apples and sweet cherries, and the common phytochemicals, quercetin and ellagic acid. Polyphenol-rich extracts were produced by solid phase extraction and column chromatography. Extracts and purified compounds were mixed into a high-fat (HF, 60%...
Production of fresh produce takes place outdoors, and therefore, is exposed to many routes of contamination (e.g., soil, contaminated water, manure, etc.) by human pathogens. Although precautions are taken to reduce this risk, pathogens can be regularly introduced to produce handling facilities. To manage the risk of cross-contamination from potentially...
Listeria monocytogenes is a foodborne pathogen frequently associated with food processing environments. Its presence is particularly concerning in facilities handling minimally processed and ready-to-eat foods. Recent outbreaks associated with fresh produce, such as packaged salads and mushrooms, highlight the need to better understand and control these pathogens in environments that...
Blackberries, genus Rubus, are an important Oregon agricultural commodity. In their fresh and processed forms, they offer many health benefits and may be able to help Americans better achieve fruit consumption recommendations because of convenience and pleasant sensory qualities. However, the susceptibility of blackberry products to contamination with bacterial pathogens...
