Wyniki wyszukiwania - Biblioteka Nauki

1

Jakość mikrobiologiczna rynkowych przypraw i ziół

100%

Berthold-Pluta A. , Kurzyńska D.

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tom nr 2

42-46

PL

Celem zaprezentowanych w artykule wyników pracy naukowo-badawczej było określenie ogólnej jakości mikrobiologicznej oraz występowania Bacillus cereus w 30 próbkach rynkowych przypraw i ziół, a także określenie wybranych cech biochemicznych i fizjologicznych wyizolowanych szczepów B. cereus. Ogólna liczba drobnoustrojów w przebadanych próbkach wahała się od 1,5x102 do 7,9x105 jtk/g, przy czym liczbę ponad 104 jtk/g stwierdzono w 40% próbek. Obecność Bacillus cereus w 1 g potwierdzono w 63,3% próbek, przy czym w połowie z nich najbardziej prawdopodobna liczba B. cereus nie przekraczała 101, a tylko w jednej próbce wynosiła ponad 103 w 1 g. Wszystkie 46 wyizolowane szczepy B. cereus rozkładały kazeinę. Zdolności do fermentacji laktozy i galaktozy nie wykazywało 91,3% i 82,6% szczepów, odpowiednio. Właściwości lipolityczne i amylolityczne wykazywało 63,0% i 82,6% szczepów, odpowiednio. Wszystkie szczepy wykazywały wzrost w warunkach 20, 30 i 37st. C/24 h, 78,3% szczepów w 43st. C/48 h, a 71,7% szczepów w 12st. C/3 dniach. Zdolności psychrotrofowe posiadało 23,9% szczepów (8st. C/10 dni), 6,5% szczepów (6st. C/10 dni) oraz 2,2% szczepów (4st. C/10 dni). Wszystkie badane próbki przypraw i ziół spełniały wytyczne ICMSF odnośnie OLD tj. <106 jtk/g, a poziom zanieczyszczenia B. cereus nie stwarzał niebezpieczeństwa zdrowotnego dla konsumentów (<104 jtk/g).

EN

The aim of this work was to study the microbiological status of 30 retail samples of spices and herbs. The samples were examined among others for the presence of Bacillus cereus. The further aim of the study was to identify particular biochemical and physiological features of the isolated B. cereus strains. The total bacterial counts (TTC) for the samples ranged from 1.5x102 up to 7.9x105 cfu/g, however 40% of the samples had counts exceeding 104 cfu/g. The presence of B. cereus per 1g was detected in 63.3 % of the samples. However the most probable number of B. cereus population did not exceed 101 in half of the samples and the number exceeding 103 per 1 g was observed only in one sample. All 46 isolated B. cereus strains were capable of hydrolysing casein. It was also found that 91.3% and 82.6% of the strains did not exhibit the ability to ferment lactose and galactose, respectively. Furthermore, 63.0% and 82.6% of the strains respectively showed lipolytic and amylolytic activity. All the examined strains grew in the following conditions: 200, 300 and 37st. C/24 hr, 78.3% of the strains grew at 43 st. C/48 hr and 71.7% at 12 st. C/3 days. In this study 23.9% (8st. C/10 days) and 6.5% (6st. C/10 days) and 2.2% (4st. C/10 days) of the strains were identified as psychrotrophic. All the examined samples of spices and herbs conformed to the ICMSF specifications regarding TTC i. e. <106 cfu/g. It was concluded that the level of B. cereus contamination (<104 cfu/g) found in the samples did not pose any potential consumer health risk.

2

Wpływ tymolu, eugenolu, aldehydu cynamonowego oraz mentolu na rozwój bakterii z rodzaju Cronobacter

100%

Fiedczak D. , Berthold-Pluta A.

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nr 1

3

Przeżywalność Bacillus cereus w jelicie cienkim

80%

Berthold-Pluta A. , Pluta A. , Leszcz G.

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tom 67

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nr 11

EN

Bacillus cereus-mediated food poisoning of the diarrhoeal type is related to the production of the following extracellular factors by the bacteria: haemolysin BL (enterotoxin HBL), non-haemolytic toxin (NHE), and cytotoxin (CytK), as well as haemolysins IV and cereolysin O, both of which have been scarcely examined and discussed in the literature. This article reviews the literature containing current data that revise former theories on the pathogenesis of the diarrhoeal form of B. cereus-mediated food poisoning. The results of in vitro studies confirming the survival of vegetative cells in the stomach and intestine environment prove that the biological state of the examined bacteria does not have any influence on the occurrence of the diarrhoeal syndrome. After contaminated food has been ingested, B. cereus spores/vegetative cells pass the stomach and reach the small intestine. There the spores can germinate to become vegetative cells that multiply and produce enterotoxins. The enterotoxins, finally, affect the intestinal epithelium, which results in diarrhoea. So far this type of food poisoning has been attributed to enterotoxin activity, excluding any kind of interaction between the host and the microorganism. However, according to the results of the latest research, the interaction between the epithelial cells and the cells of B. cereus contributes to the occurrence of infection symptoms, and the adhesion of B. cereus to the intestinal epithelium is prerequisite for the onset of the diarrhoeal syndrome. This article illustrates different aspects of B.cereus survival inside the human gastrointestinal tract, paying special attention to its lower part, i. e. the small intestine. The effect of exposure to bile salts and other factors, as well as to the indigenous microflora of the gastrointestinal tract, on B.cereus survival has been discussed. The article also elucidates issues relating to the mechanism of bacterial-epithelial cell cross-talk (interaction), which is induced when a pathogen comes into contact with enterocytes.

4

Aktywność wody produktów mlecznych. Cz. I

80%

Olkowski. M. A. , Pluta A. , Berthold-Pluta A. , Wiska J.

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tom T. 66, nr 3

31-34

PL

Niniejszy artykuł dotyczy wpływu aktywności wody (aw) na procesy biologiczne oraz przemiany chemiczne i fizyczne w wybranych produktach mlecznych. W części I artykułu omówiono podstawowe zagadnienia i definicje dotyczące aktywności wody, a także scharakteryzowano i podzielono produkty mleczne pod względem wartości tego parametru. Szczególną uwagę zwrócono na praktyczne aspekty jakości i higieny produktów w powiązaniu z aktywnością wody (aw). Przedstawiono wpływ aktywności wody na ciepłooporność mikroorganizmów, reakcje oksydacji tłuszczów i nieenzymatycznego brunatnienienia w proszku mlecznym. Opisano także przemianę szklistą, w wyniku której przyspieszona jest krystalizacja amorficznej laktozy oraz jej wpływu na pogorszenie jakości mleka w proszku.

EN

This work presents a literature review pertinent to the effects of water activity (aw) on the course of biological processes, as well as chemical and physical changes in the selected dairy products. In the first part of this manuscript the fundamentals and definitions of the water activity as well as dairy products were discussed and characterized as well as classified in terms of value for the mentioned parameter. A special attention was paid to several key aspects of practical importance for dairy product quality and hygiene. The topics elaborated in detail include the effects of aw on: micro-organisms' heat-resistance, lipid oxidation reactions and non-enzymatic browning in milk powder. There was also characterized the glass transition process, which resulted in the acceleration of amorphous lactose crystallization, as well as the effect of this change on the deterioration of milk powder quality.

5

Przeżywalność Bacillus cereus w górnych odcinkach przewodu pokarmowego

80%

Berthold-Pluta A. , Pluta A. , Leszcz G.

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tom 67

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nr 10

EN

The Bacillus cereus species of bacteria is commonly found in the environment, as well as in raw materials and foodstuffs. It may cause outbreaks of food-borne infections in humans. The course of the infection can be twofold: it can either take the form of intoxication - caused by ingestion of food containing B. cereus emetic toxin (cereulide) - or toxicoinfection, resulting from the presence of enterotoxic B. cereus strains in food which produce diarrheal type of toxins in the small intestine. The ability of B. cereus to adapt to certain stress conditions, such as low pH, can influence their survival in the gastrointestinal tract, mainly the stomach. These bacteria can initially adapt to low pH in the course of food production or in the original environment of their occurrence, i.e. in the soil. This behavior leads to a higher acid resistance of the cells and, consequently, in the case of contaminated food ingestion, it may facilitate the transit of the pathogen to the upper gastrointestinal tract. The article discusses various aspects of B. cereus survival inside the human gastrointestinal tract, paying special attention to its upper part. The issues of B. cereus capacity to counter adverse environmental conditions inside the human stomach, as well as the so called cross-resistance of the bacteria have been elucidated. The following factors have been taken into consideration: the biological state of bacteria (vegetative or spore form), growth temperature profile, phases of vegetative cell growth, as well as the possible prior exposure of the bacteria to low pH. The influence of these factors on the resistance of B. cereus spores and vegetative forms to high acidity has been examined. Finally, the effect of digestive enzymes (pepsin) on the survival of B. cereus spores and vegetative forms in the medium simulating the human stomach environment have been analyzed.

6

Sery pleśniowe – występowanie bakterii Listeria monocytogenes. Charakterystyka i ocena zagrożenia

80%

Stasiak-Różańska L. , Kraśniewska K. , Berthold-Pluta A.

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2018

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tom T. 72, nr 3

36--40

PL

Królestwem serów pleśniowych jest Francja, a każdy region tego kraju kojarzy się z wyjątkowym aromatem i docenianym przez koneserów smakiem sera. Najbardziej znane sery pleśniowe to Camembert, Brie (porośnięte pleśnią) oraz Roquefort (przerośnięte pleśnią). W Polsce produkcja serów pleśniowych rozpoczęła s ię w latach 60. XX w. Jednak produkty te nigdy nie zyskały na naszym rynku tak wielu zwolenników, ilu jest w sąsiednich krajach europejskich. Sceptycyzm rodzimych konsumentów wynika poniekąd z upodobań do tradycyjnych smaków, jakkolwiek nie brakuje osób, które w nieuzasadnionej obawie przed zagrożeniem spożycia pleśni unikają tego rodzaju produktów. W naszej kulturze panuje również przekonanie, że kobiety w ciąży powinny unikać serów pleśniowych z obawy przed ryzykiem występowania w nich patogennych bakterii z gatunku Listeria monocytogenes. Czy słusznie? W artykule przedstawiono ogólną charakterystykę serów pleśniowych oraz omówiono zagrożenia wynikające z ewentualnej obecności w nich bakterii z gatunku Listeria monocytogenes.

EN

France is the kingdom of mould cheese. Each region of this country is associated with the unique flavour and taste of cheese appreciated by the connoisseurs. The most popular mould cheeses are Camembert, Brie (covered by mold) as well as Roquefort (overgrown with mold). In Poland, the production of mould cheese was commenced in the 1960s. However, these products have never gained as many supporters on our local market as there are in neighboring European countries. The skepticism of native consumers results somewhat from preferences to traditional flavors, although there are many people who, unreasonably afraid of the risk of mold consumption, avoid this type of products. In our culture there is also an opinion that women in pregnancy should avoid mould cheese for fear of risk of occurrence of pathogenic bacteria from the genus Listeria monocytogenes in these products. Is it right? The article presents the general characteristics of mold cheese and discusses the threats resulting from the possible presence of Listeria monocytogenes in the mould cheese.

7

Aktywność wody produktów mlecznych. Cz. II

80%

Olkowski. M. A. , Pluta A. , Berthold-Pluta A. , Wiska J.

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tom T. 66, nr 4

12-17

PL

W artykule omówiono zagadnienia dotyczące wpływu aktywności wody na dojrzewanie i cechy serów, wytwarzanie kwasów organicznych przez bakterie mlekowe i ich rozwój w mleku fermentowanym oraz na zdolność do przeżycia i rozwoju pożytecznej i szkodliwej mikroflory w produktach mlecznych. Ponadto scharakteryzowano wpływ aktywności wody na zdolność katalityczną enzymów oraz opisano korelację pomiędzy ilością wytwarzanych przez bakterie mlekowe kwasów organicznych a aktywnością wody przy produkcji mlecznych napojów fermentowanych.

EN

The second part of this review discussed the impact of water activity on: ripening and characteristics of the cheese, production of organic acids by lactic acid bacteria and their growth in fermented milk, as well as on the viability and development of microorganisms (both beneficial and saprophytic) in the dairy products. However, it was described that during cheese ripening water activity decreases. Effect of water activity on the catalytic activity of enzymes has been explained, as well as the correlation between the amount of organic acids produced by bacteria and water activity in the production of yogurt has been described.

8

Przeżywalność Bacillus cereus w pożywkach imitujących środowisko żołądka człowieka

80%

Berthold-Pluta A. , Pluta A. , Molska I. , Dolega E.

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nr 07

EN

The aim of this study has been to determine the survival ability of B. cereus vegetative cells and spores in media simulating human stomach content after the ingestion of dairy or meat products contaminated with this species. The enterotoxic strain Bacillus cereus 228 isolated from raw milk was the subject of examination in this study. The gastric media (GM) simulating human stomach content used in the study were prepared by mixing: 4.80 g NaCl, 1.56 g NaHCO₃, 2.20 g KCl, 0.22 g CaCl₂ and 25 U/l pepsin solution with sterile UHT milk (0% and 3.2% fat content) or chicken broth in a 1:1 ratio. The pH values of the media were then adjusted and ranged from 2.0 to 4.5. Spore or vegetative cell suspensions of Bacillus cereus were added to GM to obtain the target initial populations of about 6.0 log CFU/ml. Incubation was carried out for 6 h at 37°C under aerobic conditions. The study revealed that B. cereus bacteria entering the human gastrointestinal tract have the ability to survive in the conditions prevailing in the human stomach environment. The survival ability in such conditions depends on the form of the ingested cells (vegetative cells or spores), on pH values, and on the kind of food with which they enter the gastrointestinal tract. B. cereus spores are highly resistant to the acidity of the human stomach environment both in the presence of chyme (at pH ~4.5) and in the absence of chyme (at pH ~2.0), regardless of the kind of food the spores were ingested with. On the other hand, B. cereus vegetative cells show diversified resistance to the conditions in the human stomach environment, depending on the pH (the quantity of chyme) and on what food the bacteria were ingested with. After inoculation with vegetative cells no survival of the vegetative cells was observed in 1 ml of each of the applied gastric media having pH 2.0 and 2.5 in the second hour of incubation. The survival rate of the vegetative cells at pH 4.5 was: 85.4% in GM-milk (3.2% fat content), 34.5% in GM-milk (0% fat content) and 4.5% in GM-chicken.