Browsing by Author "Stone, Martha, committee member"

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Open Access
Assessment of airborne microorganisms in a craft brewery
(Colorado State University. Libraries, 2011) Miller, Amanda Leah, author; Bunning, Marisa, advisor; Stone, Martha, committee member; Hyatt, Doreene, committee member
Although pathogenic bacteria have little chance of surviving in beer due to its intrinsic antimicrobial hurdles, there are other microorganisms capable of surviving and spoiling beer. The quality of all food products including beer are not only affected by the integrity of the raw materials, and cleanliness of the equipment and packaging materials, but also by the purity of the environmental air surrounding the processing area. The purpose of this project was to examine the environmental microbial air quality within various areas of a craft brewery with special emphasis on potential beer spoiling bacteria. First, samples inside the brewery and samples outside the brewery were collected to establish a baseline of data, identify areas of concern, and to examine the effect of seasonality. Those areas of concern then were sampled more often and also were sampled based on the risk of product contamination. The canning line within the brewery was identified as a specific area of concern. Bottling and canning lines in breweries often are considered non-closed production equipment and have the ability to become contaminated from outside sources including the environment. The air was sampled 307 times over a period of 22 months using an automated impaction sieve sampler pulling 80 liters of air. Samples were plated both aerobically and anaerobically. The aerobic plates were used for a general cleanliness of the area while the anaerobic plates were included to examine for beer spoiling organisms. The standard (specification limit) used for the indication of a contaminated area was a plate with 40 colony forming units (CFU) or more per 80 liters of air sampled. The results of this study revealed that testing for airborne microorganisms is highly recommended in the craft brewing industry due to the potential for the impurity of the environmental air surrounding the processing area. Seasonality had an effect on total number of aerobic airborne microorganisms with the spring months being approximately five times higher than other months. The canning line in the brewery was found to be contaminated with beer spoiling bacteria on average 75% of the time. Critical areas in the brewery, such as the bottling and canning lines, should be routinely tested for airborne microorganisms as they could lead to final product contamination. Routine microbial environmental air testing is a good indicator of overall brewery cleanliness.
Open Access
Estimation of capsaicinoid compounds and other nutritionally important compounds in Colorado grown pepper cultivars
(Colorado State University. Libraries, 2021) Hamed, Mansor, author; Jayanty, Sastry S., advisor; Wallner, Stephen, committee member; Bartolo, Michael, committee member; Stone, Martha, committee member; Manter, Daniel, committee member
To view the abstract, please see the full text of the document.
Open Access
Farm food safety plans: customizing educational materials for small-scale and campus-based farms
(Colorado State University. Libraries, 2017) Morris, Rachael E., author; Bunning, Marisa, advisor; Uchanski, Mark, committee member; Stone, Martha, committee member; Sullins, Martha, committee member
A comprehensive farm food safety plan is an integral part of all growing operations, regardless of size, output, or production practice. As small-scale and campus-based, student-run farms grow in popularity, there is an increasing need to establish the concept of comprehensive produce safety practices as a vital part of the farming process. Moreover, the passing of the Food Safety Modernization Act (FSMA) in 2011 addresses mandated accountability for large-scale agriculture within the Produce Safety Rule, but leaves many small farms exempt from regulation, including the types of farms targeted within this study. A need for a curriculum addressing produce safety on campus farms and small-scale operations, and lack of literature surrounding food safety training curriculum development drove the research design for this project. The components of this study were three fold: 1) university and college campus farm managers (n=12) from 14 states were surveyed on current practices; 2) classroom and on-farm presentations were developed and delivered to Colorado State University horticulture students (n=54), and a pre-and post- questionnaire was delivered to assess learning objectives; and 3) three on-line modules and a 27-page farm plan template were developed for Colorado growers, detailed during a webinar for Colorado Fruit and Vegetable Growers Association (CFVGA) members (participants n=33). Results offered positive a relationship between resource delivery and food safety knowledge for both students and growers. The pre-and post-questionnaire responses showed change (p≤0.05), including Likert scale questions stating that farm workers (p=0.001) and volunteers (p<0.0005) should receive food safety training. Post-webinar polling questions revealed that 100% (n=21) of voluntary respondents learned something new during the webinar, which focused on utilization of resources to build and modify farm food safety plans for any growing operation. With the national movement toward a prevention-focused food safety strategy, the need for implementing better produce safety practices has been identified as a top priority. Review and feedback from this study will aid in the continued development of materials for both campus and small-scale growers to expand their food safety practices.
Open Access
Influence of barley genetics on beer chemistry, flavor, and flavor stability
(Colorado State University. Libraries, 2017) Bettenhausen, Harmonie M., author; Bunning, Marisa, advisor; Heuberger, Adam, advisor; Avens, Jack, committee member; Broeckling, Corey, committee member; Stone, Martha, committee member
In the brewing industry, identifying superior ingredients that provide distinct flavors is an important area of research. While the contribution of raw ingredients such as yeast and hops to flavor is well understood, it is currently unclear if different genotypes of barley provide unique flavor to beer. In brewing, barley is malted to provide saccharides and enzymes for fermentation, however the malt also contains thousands of metabolites that may influence flavor. The goals of this study were to determine (i) if there would be metabolite differences among six commercial barley genotypes, (ii) if differences in barley chemistry are reflected in the chemistry of the beer, (iii) if the differences in the beer chemistry impact sensory attributes of beer, through flavor and flavor stability, and (iv) if there are barley and/or malt metabolites that can be markers for beer flavor and/or flavor stability. Six distinct malts were brewed into six beers using a recipe designed to evaluate differences in flavor. The malts were derived from the barley genotypes: Copeland, Expedition, Full Pint, Meredith, Metcalfe and PolarStar were grown and malted in either Canada or the U.S. Metabolomics was used to characterize chemical variation among the six malts and beers using RP-UHPLC-MS, HILIC-MS (non-volatile metabolites), HS/SPME-GC-MS (volatiles), and ICP-MS (metals). The metabolomics analysis detected 5,042 compounds in malt, and 217 were annotated as known metabolites and included amines (20 metabolites), amino acids (36), fatty acids/lipids (40), sugars (11), phenols (30), and others (80). A total of 4,568 compounds were detected in beer and included 246 annotated metabolites and included amines (9), amino acids (37), fatty acids/lipids/fatty acyls (28), sugars (10), phenols (20), esters (89), aldehydes (21), others (31). The chemical profiles of the six malts and beers were evaluated for metabolite variation using principal component analysis (PCA) and analysis of variance (ANOVA). Principal component analysis was conducted on the annotated metabolites and demonstrated that each of the six malts and beers contained unique chemical profiles. ANOVA characterized 150/217 malt metabolites (69.1%) and 150/246 beer metabolites (60.9%) varied among genotype (ANOVA, FDR adjusted p < 0.05). The six beers were evaluated for flavor using a modified Quantitative Descriptive Analysis® (QDA) for 45 sensory traits at 0, 4, and 8 weeks of storage at 13 °C. PCA characterized flavor differences among the six beers at 8 weeks and Full Pint was described as fruity and Meredith as corn chip. The metabolite and sensory data were integrated using two approaches: Spearman's correlation and two-way orthogonal projection to latent structures (O2PLS). The analyses revealed associations between fruity or corn chip flavor in beer with beer purines/pyrimidines, volatile ketones, amines, and phenolics; and malt lipids, saccharides, phenols, amines, and alkaloids. Taken together, these data support a role of barley metabolites in beer flavor and flavor stability. As a raw ingredient, malted barley genotypes should be evaluated for a contribution to flavor, and this may be a future target for plant breeding efforts to selectively improve flavor and flavor stability quality in beer.
Open Access
Microbial quality of mixed salad greens and selected fresh and dried herbs
(Colorado State University. Libraries, 2010) Woo, Daniel Lee, author; Bunning, Marisa, advisor; Goodridge, Larry, committee member; Stone, Martha, committee member
Direct marketing has been growing in the Western U.S., with 2007 sales of direct-marketed agricultural products totaling nearly $142.6 million in Colorado, New Mexico, Oregon, Idaho, Nevada and Washington-more than twice the 1997 sales level for the region. In addition, the number of farms engaging in direct sales to consumers grew by more than 20% to 18,274 in 2007. With increasing foodborne outbreaks linked to produce consumption, more research is needed to fill in the gaps of knowledge on the microbiological quality of leafy salad greens. Limited research has been conducted on the microbial safety and quality of farmers' market leafy salad greens. This study surveyed the microbial quality of salad greens from Larimer County farmers' markets in conjunction with salad mixes from a local supermarket. Leafy salad greens were obtained weekly for a period of four weeks from September to October, 2009, from both farmers' markets and supermarkets. Total aerobic and coliform counts were assessed within 48 hours of obtaining the samples via plating onto Petrifilm plates, then following one week of storage at refrigeration temperatures to observe changes in the microbial load. In addition, handling methods and temperatures were also recorded. Gloves and tongs were not used by vendors when handling salad greens. The vendors surveyed also lacked adequate refrigeration or ice for holding salad greens. Farmers' market salad greens were lower than supermarket salad greens in terms of initial aerobic plate counts. Both farmers' market and supermarket salad greens had no detectable levels of Escherichia coli and low levels of coliforms. After 1 week of storage, aerobic counts were higher in all samples (P<0.05). Coliform counts tended to decrease in all samples but no significant differences were observed (P>0.05). The results reiterate the need for consumers to thoroughly wash their salad greens. Further research should be conducted to assess the microbial quality o~ other produce at local farmers' markets. Herbs are often used in cooking to add aroma and flavor to foods. Consumers may choose to dry herbs from their garden or purchased from the market. Herbs, like other agricultural produce, may be exposed to a wide range of potential microbial contamination. There is currently little research on safe drying practices of herbs at home. Microwaving herbs is a potentially popular and time-saving approach for drying herbs at home. This research project investigated the impact of three drying methods (microwave, dehydrator, and conventional air drying) for improving the microbial quality of dried parsley and cilantro. Herb samples were obtained weekly from a local supermarket for a 2 month period from January to March, 2010. Standard guidelines from Oregon State University Extension service were followed for microwave drying of herbs. The manufacturer's drying temperatures/times were used for drying herbs in a dehydrator. Herbs were also air-dried for 1 week. Microbial testing was performed using plating onto 3M Petrifilm and when counts were below the detection limit, via the Most Probable Number (MPN) method. Microwave drying provided the greatest reduction in aerobic counts of bacteria in herbs. All drying methods reduced coliform counts to undetectable amounts; however, the determination of the effectiveness of each drying method in comparison with others for reducing the coliform count was complicated by the low initial load of coliforms in herbs used in the study.
Open Access
Minimizing the storage losses of potatoes under different storage treatments
(Colorado State University. Libraries, 2021) Emargi, Esam, author; Jayanty, Sastry S., advisor; Wallner, Stephen, advisor; Stone, Martha, committee member; Manter, Daniel, committee member
To view the abstract, please see the full text of the document.
Embargo
Molecular and sociocultural exploration of sourdough: impacts on gluten sensitivity and bread characteristics
(Colorado State University. Libraries, 2023) Clark, Caitlin, author; Van Buiten, Charlene, advisor; Stone, Martha, committee member; Weir, Tiffany, committee member; Gentile, Chris, committee member; Prenni, Jessica, committee member
Sourdough is a bread product fermented by communities of wild bacteria and fungi known as a starter culture. Previous work has examined the effects of specific starter organisms on bread quality, but the relationships between whole microbiomes and dough/bread physicochemical properties are currently unknown. The objective of this study was to investigate the relationship between physicochemical properties of sourdough breads and the microbiomes of their starter cultures. Twenty sourdough starters with characterized microbiomes were used to produce wheat-based dough and bread. The chemical properties (pH, titratable acidity, free amino acids, Aw) of dough and physical properties (loaf volume, crust color, texture) of the breads were compared to a control fermented with baker's yeast. The degradation and toxicity of gliadin resulting from fermentation with the sourdough samples was also studied in vitro. Results indicate that sourdough-fermented breads produced under real-world conditions are distinct from yeast-fermented bread in terms of physicochemical parameters and proteolysis, which may exert downstream effects on the inflammatory capacity of gluten. We also investigated the beliefs and behaviors of gluten-sensitive sourdough consumers and professional sourdough bakers. We found that commercial sourdough is not reported to relieve gluten-mediated symptoms for consumers diagnosed with celiac disease (CD) or non-celiac gluten sensitivity (NCGS), but undiagnosed (UD) gluten-sensitive consumers may benefit from it. We also determined that sourdough bakers act as brokers of health advice in the gluten-sensitive community.
Open Access
Profiling and putative aroma biomarker identification for flavor in potatoes using a trained sensory panel and HS-SPME GC-MS
(Colorado State University. Libraries, 2017) Bough, Raven, author; Jayanty, Sastry, advisor; Holm, David G., advisor; Stone, Martha, committee member
Flavor is the synthesis of taste and aroma sensations. The taste fraction of flavor, including salty, sweet, sour, bitter, and savory, refers to non-volatile chemical compounds that are detected by epithelial cells in the mouth. The aroma fraction encompasses volatile or semi-volatile chemical compounds that are sensed by nerve cells within the olfactory system, particularly during the chewing process, initiating a multitude of sensations such as earthy, floral, or fruity. Flavor may also be influenced by texture, sound, appearance, or personal preference, resulting in an inherently complex phenotypic trait that is difficult to assess. Cooked flavor profiling of fifteen fresh market potato clones (Solanum tuberosum, L.) using sensory analysis paired to aroma compound analysis reveals potential biomarkers for flavor phenotyping. Trained sensory panelists described extensive, significant sensory differences between potatoes including bitter, buttery, creamy, earthy, fruity, off-flavors other than bitter, potato-like flavor, sweet, woody, appearance, aroma intensity, mealy texture, and overall quality (mixed model ANOVA, α=0.05, n=17-38 ratings x 15 clones). Non-targeted volatile metabolomics with headspace solid-phase microextraction gas chromatography coupled to mass spectrometry (HS-SPME GC-MS) facilitated identification of 42 unique metabolites with significant variation across samples (ANOVA, α=0.05, n=5 technical replicates x 14-15 clones x 2 cooking methods). Based on Spearman's rank correlations, hierarchical clustering analysis (HCA), and principal component analysis (PCA), potential biomarkers for buttery, a positive flavor attribute, are aldehydes 1-nonanal, benzaldehyde, (E)-2-heptenal, pentanal, 2-phenylacetaldehyde, the alcohol (Z)-2-methyl-2-penten-1-ol, and 5-methyl-2-hexanone, a ketone. Other positive flavor attributes, sweet and potato-like flavor, are related to benzoate-3-methyl-2-buten-1-ol, 2-ethylfuran, and 3,4,5-trimethyl-2-cyclopenten-1-one. Potential biomarkers for negative flavor attributes are also implicated. Additionally, some sensory and aroma compound differences occur between baked versus boiled potatoes. Flavor biomarkers may play a key role in achieving flavor quality improvement through breeding and selection.