E. coli O157:H7 has been found to survive in dry sausages and cause disease. Isothiocyanates have been studied for their capacity to eliminate pathogens from foods and are attractive from the consumer perspective because of their natural origin. There is a need to better understand how isothiocyanates kill microorganisms and their behaviour in food matrices. It was found that glutathione and cysteine naturally present in meat can react with AIT, forming a conjugate with no or low bactericidal activity against an E. coli O157:H7. In addition, AIT presented higher anti-E. coli activity at lower pH values; therefore, it should be more efficient in acid foods. AIT was also found to inhibit the activity of thioredoxin reductase and acetate kinase; hence, enzymatic inhibition may represent a way in which AIT kills E. coli O157:H7. Mustard powder is used as a spice (active myrosinase) and/or binder (inactive myrosinase) in meat products. Both of these powders killed E. coli O157:H7 in dry fermented sausage. This was not expected since the powder lacking myrosinase is not able to produce isothiocyanates. Starter cultures and E. coli were found to consume significant amounts of glucosinolates. Pediococcus pentosaceus UM 121P and Staphylococcus carnosus UM 123M (higher myrosinase-like activity) were compared against P. pentosaceus UM 116P + S. carnosus UM 109M for their ability in reducing E. coli viability in dry sausage. Sausage batches containing powders of hot mustard, cold mustard, autoclaved mustard and no powder were prepared. Both pairs of starters yielded similar results. Reduction >5 log CFU/g of E. coli O157:H7 occurred after 31 d for hot powder and 38 d for cold powder; there was no reduction in the control. E. coli O157:H7 itself has greater effect on glucosinolate degradation than either pair of starters, which may be more important in determining its survival. Autoclaved powder caused >5 log CFU/g reduction after 18 d. This may be the result of synergistic/additive interaction among E. coli O157:H7 myrosinase-like activity, the presence of newly formed/released antimicrobials in the autoclaved powder and the multiple hurdles present in the dry sausage. Autoclaved mustard powder has potential as a novel food ingredient for the meat industry.

Yellow and oriental mustards deodorized by a laboratory autoclave method have been shown to reduce the number of E. coli O157:H7 greater than the mandatory 5 log CFU/g during sausage manufacture. However, E. coli O157:H7 was inconsistently controlled by different deodorized mustards. The antimicrobial action of mustard results from the conversion of naturally present glucosinolates into inhibitory isothiocyanates by plant myrosinase in untreated hot mustard and by bacterial myrosinase-like activity when present in thermally-treated (deodorized) mustard. Variable results with deodorized mustards suggested that plant myrosinase might not have been completely inactivated during laboratory thermal treatment using the autoclave. Results obtained showed that when a 2 cm thick layer of mustard was used during autoclave treatment, plant myrosinase activity periodically remained. However, the completely deodorized mustard failed to reduce bacterial viability as effectively as yellow mustard containing residual or slight amount of myrosinase. As a result, a small amount of myrosinase activity was highly likely contribute to the overall antimicrobial activity of deodorized mustard against E. coli O157:H7 in dry sausage.

E. coli O157:H7 has been found to survive in dry sausages and cause disease. Isothiocyanates have been studied for their capacity to eliminate pathogens from foods and are attractive from the consumer perspective because of their natural origin. There is a need to better understand how isothiocyanates kill microorganisms and their behaviour in food matrices. It was found that glutathione and cysteine naturally present in meat can react with AIT, forming a conjugate with no or low bactericidal activity against an E. coli O157:H7. In addition, AIT presented higher anti-E. coli activity at lower pH values; therefore, it should be more efficient in acid foods. AIT was also found to inhibit the activity of thioredoxin reductase and acetate kinase; hence, enzymatic inhibition may represent a way in which AIT kills E. coli O157:H7. Mustard powder is used as a spice (active myrosinase) and/or binder (inactive myrosinase) in meat products. Both of these powders killed E. coli O157:H7 in dry fermented sausage. This was not expected since the powder lacking myrosinase is not able to produce isothiocyanates. Starter cultures and E. coli were found to consume significant amounts of glucosinolates. Pediococcus pentosaceus UM 121P and Staphylococcus carnosus UM 123M (higher myrosinase-like activity) were compared against P. pentosaceus UM 116P + S. carnosus UM 109M for their ability in reducing E. coli viability in dry sausage. Sausage batches containing powders of hot mustard, cold mustard, autoclaved mustard and no powder were prepared. Both pairs of starters yielded similar results. Reduction >5 log CFU/g of E. coli O157:H7 occurred after 31 d for hot powder and 38 d for cold powder; there was no reduction in the control. E. coli O157:H7 itself has greater effect on glucosinolate degradation than either pair of starters, which may be more important in determining its survival. Autoclaved powder caused >5 log CFU/g reduction after 18 d. This may be the result of synergistic/additive interaction among E. coli O157:H7 myrosinase-like activity, the presence of newly formed/released antimicrobials in the autoclaved powder and the multiple hurdles present in the dry sausage. Autoclaved mustard powder has potential as a novel food ingredient for the meat industry.

Tyrimo metu naudotos laktobacilų išskyrimo, lactobacilų padermių rūgščių gamybos aktyvumo nustatymo, rauginto pieno klampumo nustatymo, bei riebalų rūgščių gamybos aktyvumo nustatymo metodikos. Darbo tikslas: Nustatyti skirtingų laktobacilų rūšių karvės ir ožkos pieno fermentacijos aktyvumą. Darbo uždaviniai: 1.Nustatyti Lactobacillus acidophilus, L. bulgaricus, L. rhamnosus, L. plantarum ir L. fermentum rūgščių gamybos aktyvumą rauginant karvės ir ožkos pieną. 2.Nustatyti ir įvertinti surauginto karvės ir ožkos pieno klampą; 3.Nustatyti skirtingų laktobacilų riebalų rūgščių gamybos aktyvumą. 4.Nustatyti Lactobacillus acidophilus, L. bulgaricus, L. rhamnosus, L. plantarum ir L. fermentum gyvybingumą rauginant pieną dvi paras. Išvados: Skirtingos laktobacilų rūšys karvės ir ožkos piene rūgštis gamino aktyviai. Didžiausiu rūgščių gamybos aktyvumu raugintame karvės piene pasižymėjo L. acidophilus, šios kultūros titruojamasis rūgštingumas 6 - ąją para buvo 220 oT, ožkos piene – L. planarum, 6 – ąją parą buvo 228 oT. Didžiausias rauginto karvės ir ožkos pieno klampumas nustatytas pieną rauginant 24 val. L. bulgaricus kultūra (atitinkamai 344,797 mPa.s ir 167,313 mPa.s). Didžiausias sočiųjų riebalų rūgščių (RR) kiekis, nuo bendro riebalų rūgščių kiekio, nustatytas karvės piene raugintame su L. bulgaricus (66,7 proc) ir L. acidophilus (62,6 proc). Didžiausias polinesočiųjų RR kiekis nustatytas pieną rauginant su L. plantarum (71,1 proc). Didžiausias sočiųjų RR kiekis... [toliau žr. visą tekstą] / During the research the following methods had been used: extraction of lactobacillus, identification of production activeness in lactobacillus tribe acids, tests of acidified milk tenacity and establishments in production activeness of fatty acids. Work aim: Determine fermentation activeness of different lactbacillus tribes in cow‘s and goat‘s milk. Work goals: 1.Determine activeness of production of Lactobacillus acidophilus, L. bulgaricus, L. rhamnosus, L. plantarum and L. fermentum in cow‘s and goat‘s milk. 2.Identyfy and evaluate cow‘s and goat‘s acidified milk of viscosity. 3.Determine production activeness of different lactobacillus fatty acids. 4.Identify Lactobacillus acidophilus, L. bulgaricus, L. rhamnosus, L. plantarum and L. fermentum viability fermentation milk for two days. Conclusions: Different types of lactobacillus in cow‘s and goat‘s milk produced acids actively. The biggest production of acids in acidified milk was performed by L. acidophilus, titrated acidity of this culture after 6 days was 220 oT, in goat‘s milk – L. planarum, after 6 days - 228 oT. The biggest cow‘s and goat‘s actified milk tenacity was found when milk was fermented for 24 h with the help of L. bulgaricus culture (accordingly 344,797 mPa.s and 167,313 mPa.s). The biggest ammount of fatty acids, from the overall fatty acid ammount, found in cow‘s milk which was fermented with L. bulgaricus (66,7 %) and L. acidophilus (62,6 %). The biggest ammount of polyunsaturates was found... [to full text]

Pasaulyje plečiasi įvairių augalų, jų sudedamųjų dalių, fermentuotų augalų panaudojimas įvairių maisto produktų gamyboje. Augalai – natūralus, atsinaujinantis aromatinėmis, antioksidacinėmis bei antimikrobinėmis savybėmis pasižymintis maisto produktų praturtinimo šaltinis. Jie turi daug biologiškai aktyvių medžiagų. Daugiausia tyrinėjamas augalų panaudojimas arbatų kompozicijose, gaiviųjų gėrimų gamyboje, konditerijoje. Pieno produktų gamyboje augalų panaudojimas mažai tyrinėjamas, tačiau perspektyvus. Darbo tikslas: Ištirti fermentinio traukinimo procesą, panaudojant fermentuotus ir nefermentuotus augalus. Ištirti nebrandintų fermentinių sūrių maistinę sudėtį, kokybę ir juslinius rodiklius. Pagaminome, tyrėme ir nustatėme nebrandintų fermentinių sūrių su fermentuotais (Glycine Max, Linum usitatissimum) ir nefermentuotais (Hibiscus rosa – sinensis, Cyclopia intermedia) augalais pH, BTR (bendrą titruojamąjį rūgštingumą), drėgmę, mikrobiologinę analizę, juslines savybes (vertinamos 5 žmonių). Apibendrinti tyrimų duomenys parodė, kad nefermentuotos H. rosa-sisnensis ir Cyclopia intermedia ekstraktai pagerino sūrių juslines savybes. Remiantis literatūros duomenimis – praturtino įvairiomis biologiškai veikliomis (aktyviomis) medžiagomis. Tuo būdu pagerino pridedamąją vertę, sūriai tapo patrauklesni vartotojams. Sūriai su fermentuotais augalais pasižymėjo savitu originaliu skoniu. Juose liko augalų (Glycine Max, Linum usitatissimum) veikliųjų dalių, padidėjo pieno rūgšties... [toliau žr. visą tekstą] / In a world there are growing variety of plants and their components, use of fermented plants in various food products. Plants – a renewable natural food source saturated with flavorings, antioxidant and anti-microbial characteristics. They have a lot of biologically active substances. Most studied plants are in the compositions of tea, soft drinks and confectionery. The use of a plants in the milk production is little studied, but still promising. The aim of work: to investigate the enzymatic clotting process using fermented and non-fermented plants. To investigate unripened cheese nutritional composition, quality and sensory characteristics. We manufactured, investigated and found unripened cheese with fermented (Glycine Max, Linum usitatissimum) and unfermented (Hibiscus rosa – sinensis, Cyclopia intermedia) plants pH, TTA, moisture, microbial analysis, organoleptic (sensory) properties (measured by 5 people). Summarized studies have shown that H. rosa-sisnensis and Cyclopia intermedia extracts of unfermented cheese improved organoleptic properties. Based on the literature – this enriched with biologically active substances. Thereby the added value improved, cheese has become more attractive to consumers. Cheese and fermented plants characterized by distinctively original taste. There remained the active parts of the plant (Glycine Max, Linum usitatissimum), increased the amount of lactic acid bacteria. In this way, cheese with fermented plants (Glycine Max, Linum... [to full text]

Biochemical properties, functional properties, and market potential of Pacific whiting (PW) fish sauce were investigated. Biochemical properties of fish sauce made from whole fish (W) and a mixture (1:1) of whole fish and surimi byproducts (WB) were compared. Market potential was evaluated through phone interviews and consumer panelists. Proteolysis was primarily affected by cathepsin B-like and L-like enzymes. Acidic pH (4-5) with low salt concentration (15-20%) provided a greater degree of hydrolysis (DH), total nitrogen, and amino nitrogen content in PW fish sauce compared to the traditional process. The greatest Angiotensin Converting Enzyme (ACE) inhibition (96.8%) was found in samples fermented with 15% salt at pH 5.0 for 30 days. Anti-oxidative activity (AT) increased when fermentation continued and depended on fermentation pH. Peptides with MW <590 Da possibly played an important role in ACE inhibition. Consumer tests disclosed no significant difference in flavor liking and overall liking among fish sauce samples (W, WB, and commercial anchovy fish sauce). / Graduation date: 2004

Three New Zealand marine species, hoki (Macruronus novaezealandiae), kahawai (Arripis trutta) and trevally (Pseudocaranx dentex) were used to develop model fermented fish sausage. The formulation comprised fish mince, carbohydrate, minced garlic and salt in a mass ratio of 1 (fish): 0.15: 0.05: 0.03, respectively. The carbohydrate source was cooked rice or glucose. (Endogenous lactic acid bacteria (LAB) failed to ferment rice). Folate was also added to the mixture as a factor. The mixtures were extruded into 50 mL plastic syringes, where the needle end of the barrel had been excised by lathe. The lubricated barrel was overfilled to 60 mL, capped with a layer of ParafilmTM and aluminium foil, sealed tightly by rubber band and incubated at 30°C. Over time the piston was progressively advanced to yield samples for microbiological, physical, and chemical analysis. Over 96 hours an increase in the LAB count was observed with a concomitant decrease in pH. After fermentation was complete, the samples contained around 8.77 log cfu LAB g-1 with the pH range from 4.38 to 5.08. The microbiological and pH behaviour of each species varied between preparations. Hardness, adhesiveness, springiness and cohesiveness of the treatments increased with fermentation, except for hoki. The treatments showed different colour characteristics with fermentation. The light reflectance (L* values) of the trevally and kahawai treatments increased, while the a* (redness) and b* (yellowness) values decreased. Hoki exhibited smaller colour changes except for yellowness, which increased markedly. Proteolysis, measured colorimetrically by soluble peptide bonds, was greatest for trevally. Lipid oxidation, measured by the thiobarbituric acid method, was least for hoki, notably the species with the lowest fat content. Biogenic amines, which are a general quality indicator of fermented products, increased during fermentation. The trevally treatment generated the highest concentration of amines, but these values were lower than those reported for fermented fish sausage in Southeast Asia. Notably there were no important difference between folate treatments and those without folate. The results point to commercial opportunities and further research with New Zealand marine species, especially trevally. To improve the product quality and to show geographical exclusivity, further research could be done by using starter culture, and a New Zealand staple carbohydrate source such as kumara and potato, and spices and herbs which are commonly used in New Zealand, such as rosemary, thyme and sage or specific to New Zealand, such as horopito. In addition, sensory studies should also be performed before the products could be tested in the market.

Three New Zealand marine species, hoki (Macruronus novaezealandiae), kahawai (Arripis trutta) and trevally (Pseudocaranx dentex) were used to develop model fermented fish sausage. The formulation comprised fish mince, carbohydrate, minced garlic and salt in a mass ratio of 1 (fish): 0.15: 0.05: 0.03, respectively. The carbohydrate source was cooked rice or glucose. (Endogenous lactic acid bacteria (LAB) failed to ferment rice). Folate was also added to the mixture as a factor. The mixtures were extruded into 50 mL plastic syringes, where the needle end of the barrel had been excised by lathe. The lubricated barrel was overfilled to 60 mL, capped with a layer of ParafilmTM and aluminium foil, sealed tightly by rubber band and incubated at 30°C. Over time the piston was progressively advanced to yield samples for microbiological, physical, and chemical analysis. Over 96 hours an increase in the LAB count was observed with a concomitant decrease in pH. After fermentation was complete, the samples contained around 8.77 log cfu LAB g-1 with the pH range from 4.38 to 5.08. The microbiological and pH behaviour of each species varied between preparations. Hardness, adhesiveness, springiness and cohesiveness of the treatments increased with fermentation, except for hoki. The treatments showed different colour characteristics with fermentation. The light reflectance (L* values) of the trevally and kahawai treatments increased, while the a* (redness) and b* (yellowness) values decreased. Hoki exhibited smaller colour changes except for yellowness, which increased markedly. Proteolysis, measured colorimetrically by soluble peptide bonds, was greatest for trevally. Lipid oxidation, measured by the thiobarbituric acid method, was least for hoki, notably the species with the lowest fat content. Biogenic amines, which are a general quality indicator of fermented products, increased during fermentation. The trevally treatment generated the highest concentration of amines, but these values were lower than those reported for fermented fish sausage in Southeast Asia. Notably there were no important difference between folate treatments and those without folate. The results point to commercial opportunities and further research with New Zealand marine species, especially trevally. To improve the product quality and to show geographical exclusivity, further research could be done by using starter culture, and a New Zealand staple carbohydrate source such as kumara and potato, and spices and herbs which are commonly used in New Zealand, such as rosemary, thyme and sage or specific to New Zealand, such as horopito. In addition, sensory studies should also be performed before the products could be tested in the market.

Thesis (M.Sc. (Microbiology))--Mahidol University, 1983.

Thesis (Ph. D.)--University of Wisconsin--Madison, 2002. / Includes bibliographical references (leaves 449-492).