Index Catalog // ScholarsArchive@OSU

Enzymatic analysis of mutant and wild type lactic streptococcus organisms developing on a selective medium

Creator:: Turner, Nikki Edwards
Resource Type:: Masters Thesis

Studies on diacetyl production by Streptococcus diacetilactis matuszewski et al

Creator:: Seitz, Eugene Walter
Resource Type:: Dissertation

Isolation of auxotrophic mutants of Bacillus cereus

Creator:: Keng, Jiun Guang
Abstract:: Bacillus cereus excretes large amounts of penicillinase into growth media during incubation, hence the widely-used penicillin selection technique for isolating biochemical mutants of bacteria is not applicable to this species. Genetic transfer in B. cereus has not been reported; this is partly due to the lack of an effective isolation...
Resource Type:: Masters Thesis

Genetic homology and exchange in lactic acid streptococci

Creator:: Knittel, Martin Dean
Abstract:: The dairy industry relies primarily on consistent acid production by the lactic streptococci for the manufacture of certain cheeses and fermented dairy products. Variation in these cultures due to genetic exchange has not been thoroughly investigated. This study was undertaken to determine if genetic homology exists within the lactic group,...
Resource Type:: Dissertation

Control of acid production and β-galactosidase synthesis in lactic streptococci

Creator:: Citti, James Edward
Abstract:: The public health and economic significance of rapid acid production by lactic streptococci in controlled dairy fermentations is well known. However, the fast acid-producing characteristic of these organisms is not stable, and cultures of fast organisms have been shown to contain slow cells. These studies were carried out to characterize...
Resource Type:: Dissertation

Effect of quaternary ammonium compounds on bacteria : comparison of sensitive and resistant strains of the same species

Creator:: Albin, Inga Anna Schroder
Abstract:: To determine whether some bacteria are more susceptible than others to quaternary ammonium compounds, the following bacteria were grown on agar slants containing various concentrations of alkyl dimethyl ethyl benzyl ammonium chloride (ADEBAC), and alkyl dimethyl benzyl ammonium chloride (ADBAC): Aerobacter aerogenes 12658, Alcaligenes metalcaligenes, Brevibacterium linens, Chromobacterium lividum, Escherichia...
Resource Type:: Masters Thesis

Host range and chemical composition of lactic streptococcal bacteriophages

Creator:: Henning, David Ralph
Abstract:: Comparisons were made of the abilities of Streptococcus lactis, Streptococcus cremoris and Streptococcus diacetilactis bacteriophages to endure various laboratory isolation and storage treatments. Neutralization of Cottage cheese whey containing phages offered no survival advantage over unneutralized samples, refrigeration of neutral and acid whey samples increased the survival of only the...
Resource Type:: Dissertation

Studies on mutation and lactose fermentation in lactic streptococci

Creator:: Wagner, Sally Ann
Abstract:: This study involved an investigation of lactic streptococci which had irreversibly lost ability to produce the high levels of acid in milk necessary during the manufacture of certain fermented dairy products. The slow acid producing mutants studied were obtained from a normal acid producing strain by natural selection following induction...
Resource Type:: Masters Thesis

Factors related to resisitance of bacteria to quaternary ammonium germicides

Creator:: Wang, Wei-sheng
Abstract:: This study was carried out to compare the effects of a quaternary ammonium compound (QAC) upon strains of Pseudomonas aeruginosa which were either sensitive or resistant to the germicide. The cationic QAC used was alkyldimethylbenzylammonium chloride. The resistant types were isolated from the sensitive population by selection of mutants which...
Resource Type:: Masters Thesis

Some factors influencing carbon dioxide production by Leuconostoc citrovorum

Creator:: Holmes, Beverly Ann
Abstract:: This study was undertaken to determine the role Leuconostoc citrovorum may play in carbon dioxide production in milk. The ability of L. citrovorum strains to produce gas was studied by two methods. A qualitative method used visual measurement of gas where an agar plug was forced up the neck of...
Resource Type:: Masters Thesis

Pathways and enzymes involved in glucose catabolism by lactic streptococci

Creator:: Nandan, Rajiva
Abstract:: The enzymes and pathways involved in the catabolism of glucose by several strains of Streptococcus diacetilactis, Streptococcus cremoris, and Streptococcus lactis, commonly called the lactic streptococci, were studied. The presence of aldolase, triosephosphate isomerase and alcohol dehydrogenase in these organisms provided evidence for the operation of the Embden-Meyerhof-Parnas (EMP) pathway...
Resource Type:: Dissertation

Metabolism of aroma bacteria as related to diacetyl production

Creator:: Brown, Ruth Elaine
Abstract:: Factors influencing diacetyl production by the aroma bacteria Leuconostoc citrovorum and Streptococcus diacetilactis were investigated. When grown in association with lactic streptococci, L. citrovorum strain 91404 decreased in cell numbers from 10⁸ to 10⁶ over two weeks of daily subculturing in sterile non-fat milk incubated at 21°C. The ability to...
Resource Type:: Masters Thesis

Properties of Pseudomonas aeruginosa resistant to quaternary ammonium compound

Creator:: Washam, Clinton Jay
Abstract:: Pseudomonas aeruginosa cells were selected for their ability to grow in the presence of 750 ppm alkyldimethylethylbenzyl ammonium chloride (QAC). These cells were found to retain their resistance to the germicide throughout tri-weekly transfers for 7 months in tryptone glucose yeast extract (TGY) broth containing no QAC. Comparisons of the...
Resource Type:: Dissertation

Mechanisms of lactose metabolism by strains of Streptococcus lactis

Creator:: Walter, Leslie Alva
Abstract:: Rapid acid production by lactic streptococci used in the manufacture of fermented dairy products is essential to the economy of the industry and to the public health of consumers. There remains to developed, however, an adequate laboratory procedure to detect and distinguish between slow and fast strains of these bacteria....
Resource Type:: Masters Thesis

Evaluation of media inhibitory for lactic streptococcal bacteriophages

Creator:: Gulstrom, Timothy James
Abstract:: Seven commercially prepared brands of lactic streptococcal phage inhibitory media were obtained from their manufacturers. Comparisons between the different media were made with respect to buffering capacity, ability to support lactic streptococcal growth, ability to suppress bacteriophage replication, and ability to support Leuconostoc growth. Nonfat milk was used during experiments...
Resource Type:: Masters Thesis

Strain dominance in frozen multiple strain lactic starters

Creator:: Leach, Roy Dullnig
Abstract:: Two multiple strain lactic streptococcal starter concentrates were examined to determine whether or not elimination of one of the three component strains, by addition of its specific phage, resulted in disproportionate inhibition of acid production (strain dominance). Both starters showed dominance when tested three to four weeks after freezing and...
Resource Type:: Dissertation

Selection of phage insensitive lactic streptococcal strains for use in cheddar cheese manufacture

Creator:: Daniell, Suzanne D.
Abstract:: A survey was conducted of six North American cheese plants to determine levels of bacteriophages present. Fifty-nine lactic streptococcal host bacterial strains were utilized in the survey. Phage levels were generally lower in plants employing modern manufacturing techniques than in plants employing traditional manufacturing techniques; this difference was attributed to...
Resource Type:: Masters Thesis

Factors influencing the production of tyramine, histamine and tryptamine in cheese

Creator:: Edwards, Susan Thornton
Resource Type:: Masters Thesis

A comparative study of Lactobacillus acidophilus strains

Creator:: Fowlkes, Charles Edward
Resource Type:: Masters Thesis

Bacteriophage-host interactions in lactic streptococci : lysogeny, phage inhibition and phage-insensitive mutants

Creator:: Huggins, Alan Roy
Resource Type:: Dissertation

Lactic streptococcal agglutinins

Creator:: Salih, Mohammed Ali
Abstract:: Lactic streptococcal agglutinins are known to promote settling of starter bacteria in milk, resulting in spongy, mealy, shattered curd and sludge formation defects in cottage cheese. These agglutinins are natural antibodies secreted by lactating cows in mature milk in response to infections (mastitis) and in colostrum milk as protective antibodies...
Resource Type:: Masters Thesis

Lactic streptococci: growth characteristics and plasmid profiles of drug- and bacteriophage-insensitive mutants

Creator:: Wulf, John J.
Abstract:: Fast acid-producing streptomycin-resistant mutants for several strains of lactic streptococci currently used in commercial Cheddar cheese manufacture were isolated. Their isolation involved use of a recently developed differential plating medium that allows identification of fast acid-producing colonies. Both parents and mutants were characterized with regard to growth, acid production, proteolytic...
Resource Type:: Masters Thesis

Development of internally pH-controlled bulk starter media for the propagation of lactic acid bacteria

Creator:: Willrett, Douglas L.
Resource Type:: Dissertation

Comparison of Oregon-derived malolactic bacteria in pilot scale wine production

Creator:: Henick-Kling, Thomas
Resource Type:: Masters Thesis

Characterization of Oregon-derived malo-lactic bacteria : fermentation properties and storage stability

Creator:: Dohman, Thomas Philip
Abstract:: Gram positive cocci isolated from Oregon wines were characterized and their relative malate fermentation abilities compared. They were heterofermentative, catalase negative, and facultatively anaerobic. Glucose, fructose, cellobiose, maltose, ribose, trehalose, salicin and esculin were fermented by all strains. Arabinose was fermented weakly but lactose, raffinose, sucrose, xylose, rhamnose, mannose and...
Resource Type:: Masters Thesis

Internal pH control starter media: use in culture preservation and for multiple strain growth

Creator:: Shigeno, Debra S.
Abstract:: Several bulk starter media, consisting of two experimental blends and four commercial preparations, were examined for each medium's ability to grow, preserve, and/or recover lactic streptococcal starter cultures. Nonfat milk was used as a control. Results showed that cultures which had the greatest survival rate in frozen storage had been...
Resource Type:: Masters Thesis

Bacteriophages for Leuconostoc oenos : a survey of Oregon wineries

Creator:: Eschelbach, Matthew Michael
Abstract:: A study of malolactic bacteria of the Leuconostoc genus, especially L. oenos, and their bacteriophages was conducted. A search for the presence of infectious bacteriophages in grapes, musts, and juices employed in malo-lactic fermentation (MLF) was conducted; no evidence, either physical or biological, was found for the existence of these...
Resource Type:: Masters Thesis

Performance of Oregon derived malolactic bacteria : studies on storage stability and their use in the wine industry

Creator:: Micheals, Nancy J.
Abstract:: Commercial vats of Chardonnay and Pinot Noir were inoculated during yeast fermentation with starter cultures containing 10⁷ - 10⁹ cfu/ml of the malolactic bacteria Leuconostoc oenos Erla and Ey2d in lots ranging from 55 to 4,000 gallons. Chardonnay inoculated with Ey2d completed MLF in an average of 56 days at...
Resource Type:: Masters Thesis

Antimicrobial resistance and plasmid properties of Leuconostoc and group N Streptococcus

Creator:: Orberg, Paulo K.
Abstract:: A method for rapid isolation of plasmid DNA from group N streptococci was developed. Chief advantages of the method were simplicity, the utilization of microliter quantities of reagents, and the obtainment of preparations highly enriched for covalently closed circular plasmid DNA. The method was also applied to over 15 Leuconostoc...
Resource Type:: Dissertation

Studies on growth metabolites produced by Propionibacterium shermanii

Creator:: Salih, Mohammed Ali
Abstract:: The ability of Propionibacterium shermanii to produce growth metabolites which were inhibitory to food spoilage indicator organisms was investigated. Asperqillus niqer, a Pseudomonas species and Kluyveromyces fraqilis were the spoilage indicators chosen to represent molds, gram negative psychrotrophic bacteria and yeasts, respectively. Supplementation of milk or whey based media was...
Resource Type:: Dissertation

Conjugal transfer of plasmid genes between lactic Streptococcus and Leuconostoc starter bacteria

Creator:: Tsai, Huai-jen
Abstract:: Mutants of Streptococcus lactis 7962 with various combinations of plasmid molecular masses were screened for nisin production. Nisin was produced by both wild type and mutants that contained a 17.5 Md plasmid, which was usually obscured by the chromosomal fragments. No nisin was produced by plasmid-free mutants. Sucrose fermentation and...
Resource Type:: Dissertation

Preservation studies on internal-pH-control-grown yogurt starters

Creator:: Matalon, Marcelo E.
Resource Type:: Masters Thesis

Studies to improve lactic acid bacterial starter cultures

Creator:: Khosravi, Lewa
Abstract:: Three commercial sausage starter cultures were grown in an internal-pH-controlled medium (PHASE 4) and in a soluble phosphate-buffered medium. The cultures were tested by comparing viable counts before and after freezing at -40 C or freeze-drying and subsequent storage for 3 months in the frozen or dried state. Strains varied...
Resource Type:: Dissertation

Genetics of Lactobacilli : plasmid profiles and genetic exchange

Creator:: Scarlett, Lori M.
Abstract:: Lactobacilli are microorganisms with many applications in the fermented food and dairy industries. In addition to the actual fermentation of food products, lactobacilli are involved in the metabolic breakdown of lactose in dairy products, enabling a large population of lactose-intolerant humans to ingest milk. Lactobacilli are also used as health...
Resource Type:: Masters Thesis

Development of bacteriophage inhibitory bulk starter medium for the cultivation of thermophilic lactic acid bacteria

Creator:: Rajagopal, S. N.
Abstract:: Internally-pH-controlled, phosphate containing and non-phosphate containing Italian bulk starter media were compared to reconstituted nonfat dry milk and commercial bulk starter media for their ability to support the growth and activities of commercially frozen thermophilic lactic acid cultures. Cultures grown in internally-pH-controlled media demonstrated superior acid-production capability. The cheese made...
Resource Type:: Dissertation

Growth of lactococci relative to antibiotic and quaternary ammonium compounds

Creator:: Valladao, Marilin
Abstract:: The work presented in this thesis is concerned with the effect of several antibiotics and quaternary ammonium sanitizers upon growth of lactic acid bacteria. Section I reports the purification of beta-lactamase from Lactococcus cremoris PR-108, by ion exchange chromatography, using the chromogenic substrate pyridine-2-azo-p-dimethylaniline (PADAC) as the enzymatic indicator. Section...
Resource Type:: Masters Thesis

Characterization of thermophilic rod and coccus starter strains used in mozzarella cheese manufacture

Creator:: Faessler, Patrick Charles
Abstract:: The present investigation was undertaken to characterize a number of strains of Lactobacillus bulgaricus and Streptococcus thermophilus intended for use by a commercial starter supply company. Thorough characterization of each culture was required in order to combine compatible strains so that their usefulness in Mozzarella cheese manufacture would be maximized....
Resource Type:: Masters Thesis

Development and use of genetic techniques for study of dairy Leuconostoc bacteria

Creator:: Wyckoff, Herbert Allen, 1961-
Resource Type:: Dissertation

Application of bacteriocins produced by lactic acid bacteria in preserving dairy products and development of a selective medium for Leuconostoc isolation

Creator:: Benkerroum, Noreddine
Resource Type:: Dissertation

The isolation of Lactococcus lactis subsp. cremoris from nature with probes for 16S ribosomal RNAs

Creator:: Salama, Maysoon
Resource Type:: Dissertation

Effects of propionibacterial metabolites on spoilage and pathogenic bacteria in dairy products

Creator:: Teo, Alex Yeow-Lim
Resource Type:: Masters Thesis

Development of an internal pH-controlled, phage inhibitory bulk starter medium for the propagation of thermophilic lactic acid bacteria used in the production of mozzarella cheese

Creator:: Whitehead, William E.
Resource Type:: Dissertation

Screening of Sporolactobacillus and Bacillus strains for use in silage inoculation

Creator:: Smoker, Amy N.
Resource Type:: Masters Thesis

Characterization of 16S Ribosomal RNA Probe-Isolated Lactococci from nature for use in Cheddar cheese manufacture

Creator:: Daniels, Brent E.
Abstract:: Strains of Lactococcus lactis ssp. lactis and Lactococcus lactis ssp. cremoris with potential use in the food industry which had been previously isolated from nature using 16S rRNA probes were characterized for unique identifying traits and for attributes important for potential use in cheese manufacture. Strains of Lc. cremoris which...
Resource Type:: Masters Thesis

Roles of yeast and lactic acid bacteria in malolactic fermentation of wines : a chemical and sensory study

Creator:: Avedovech, Richard M.
Abstract:: The purposeful induction of malolactic fermentation (MLF) in wines such as Pinot Noir and Chardonnay is an established commercial wine making practice in Oregon. This induction is not always successful, especially with white wines, such as Chardonnay. A study was initiated to examine the compatibility of yeasts commonly used in...
Resource Type:: Dissertation

Growth, physiological characteristics and plasmid profiles of Bifidobacterium species

Creator:: Cheng, Ronshan
Abstract:: The fecal flora of healthy bottle or breast-fed infants was examined for the presence of Bifidobacterium. Identification was based on the presence of fructose-6-phosphate phosphoketolase, which is found only in these bacteria. No bifidobacteria were recovered from bottle-fed infants. However, bifidobacteria were readily isolated from 15 day to 3 month...
Resource Type:: Masters Thesis

Some microbiological and sensory characteristics of Cheddar cheese manufactured from conventional and ultrafiltered-concentrated milk

Creator:: Betancur, Carmen L.
Abstract:: Cheddar cheese making from ultrafiltered (UF) concentrated milk potentially increases yield, saves raw materials, cuts transportation costs, minimizes waste pollution, and stream-lines production. However, the resulting UF-cheese has been found to differ from conventionally made cheese (CM-cheese) in its casein matrix and ripening process. UF and CM Cheddar cheeses were...
Resource Type:: Masters Thesis

Microbiological control of food spoilage and pathogenic microorganisms in refrigerated foods

Creator:: Al-Zoreky, Nageb
Abstract:: Microgard, a commercially-available pasteurized fermented milk, was found inhibitory to gram negative bacteria such as Pseudomonas putida, some well-known foodborne pathogens (e.g. Salmonella, Yersinia and Aeromonas) and some fungi as revealed by an agar incorporation assay method. Gram positive bacteria, however, were not inhibited. Rather, some bacteria in this group...
Resource Type:: Masters Thesis

Effect of selected lactic acid bacteria on the growth of food-borne pathogens and spoilage microorganisms in raw milk and milk products

Creator:: Al-Zoreky, Nageb
Abstract:: Several lactic acid bacteria (LAB) of the Lactococcus, Lactobacillus, Leuconostoc and Pediococcus genera were screened for inhibition of food-borne pathogens and spoilage microorganisms in raw milk and dairy products. Listeria monocytogenes was killed by Lactococcus lactis subsp. lactis and Pediococcus pentosaceus due to their production of bacteriocin-type inhibitors. Staphylococcus aureus...
Resource Type:: Dissertation

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