Template-Type: ReDIF-Article 1.0 Author-Name: Ľ. Valík Author-Workplace-Name: Department of Nutrition and Food Hygiene, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava, Slovak Republic Author-Name: F. Görner Author-Workplace-Name: Department of Nutrition and Food Hygiene, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava, Slovak Republic Author-Name: D. Lauková Author-Workplace-Name: Department of Nutrition and Food Hygiene, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Bratislava, Slovak Republic Title: Growth dynamics of Bacillus cereus and shelf-life of pasteurised milk Abstract: Growth dynamics of Bacillus cereus in pasteurised milk was examined in storage tests performed at 5, 7, 9, 11, and 13°C. The contents of B. cereus in pasteurised milk ranged from the absence in 4 ml of milk to 2.3 cfu/ml. The initial total plate counts varied from 1.1 × 104 to 3.0 × 104 cfu/ml (n = 15). Growth curves of Bacillus cereus showed that strains naturally present in pasteurised milk grew well at 5 and 7°C. A square root model was used for the growth rate analysis in relation to the storage temperature of milk (√μ = 0.026 (T - Tmin); R2 = 0.93). Lag-time of B. cereus was described by a modified Arrhenius-type equation (λ = -45.667 + 1035.3/T; R2 = 0.94). The comparison of the time prediction calculated for B. cereus to reach the density of 104 cfu/ml in pasteurised milk and that for the total plate counts to reach levels of 5.0 × 104 cfu/ml proved that these plate counts were reached in all tests earlier than the level of 104 cfu/ml could be reached by B. cereus. It is thus concluded that pasteurised milk is spoiled by the growth of saprophytic psychrotrophic bacteria before B. cereus can produce hazardous levels of its enterotoxin. Keywords: pasteurised milk, B. cereus, shelf-life Journal: Czech Journal of Food Sciences Pages: 195-202 Volume: 21 Issue: 6 Year: 2003 DOI: 10.17221/3498-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3498-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200306-0001.txt Handle: RePEc:caa:jnlcjf:v:21:y:2003:i:6:id:3498-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: L. Červenka Author-Workplace-Name: Department of Analytical Chemistry and Author-Name: I. Zachová Author-Workplace-Name: Department of Analytical Chemistry and Author-Name: P. Minříková Author-Workplace-Name: Department of Analytical Chemistry and Author-Name: J. Vytřasová Author-Workplace-Name: Department of Analytical Chemistry and Title: Effect of pH and water activity on the growth of Arcobacter sp. in culture Abstract: The effect was studied of pH value and water activity (aw) on the growth of Arcobacter butzleri and Arcobacter cryaerophilus in culture media at 30°C. Various weak organic acids were used to achieve target pH, and different humectants were used to control aw. Generally, the growth of arcobacters was inhibited at medium pH. Compared to propionic, lactic, malic and ascorbic acids (pH 5.5-5.0), formic, citric and tartaric acids in the pH range of 6.0-5.5 were more inhibitory to both arcobacter species. Both arcobacter strains were extremely sensitive to broth environment with aw values of < 0.980 using NaCl, glycerol and sucrose as humectants. This sensitivity to aw and pH may well be an important constraint for the distribution and survival of Arcobacter sp. in the environment, particularly in foods and food products. Keywords: Arcobacter sp., weak organic acids, water activity Journal: Czech Journal of Food Sciences Pages: 203-209 Volume: 21 Issue: 6 Year: 2003 DOI: 10.17221/3499-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3499-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200306-0002.txt Handle: RePEc:caa:jnlcjf:v:21:y:2003:i:6:id:3499-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Hrušková Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: I. Švec Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Author-Name: I. Kučerová Author-Workplace-Name: Department of Carbohydrate Chemistry and Technology, Institute of Chemical Technology, Prague, Czech Republic Title: Effect of malt flour addition on the rheological properties of wheat fermented dough Abstract: The bread-making quality of forty three wheat flour samples, divided into two groups according to the ash content (up to 0.6% and 0.7%), and its changes by fortification with malt flour were studied in the form of fermented dough. Standard analytical measurements (ash and protein contents, wet gluten, falling number, Zeleny sedimentation value), rheological investigations (amylograph, maturograph, oven rise recorder), and laboratory baking test were used for the characterisation of flour and dough. The influence of the malt flour addition on the fermented dough behaviour depends on the flour composition and was found more significant in flours with a lower ash content ("bright" type). Amylograph characteristics of flour-water suspensions were affected in the same extent by the malt addition. Maturograph behaviour changed significantly only in proofing stability (without influence by the flour type) and dough firmness was affected by malt only in the case of flours with lower ash contents. Oven rise characteristics of dough and the specific bread volume showed important changes in both sets of samples with significant differences between flours with lower and higher ash contents. A strong correlation (r = 0.62-0.75) significant at 0.01 level exists between the specific bread volume and all oven rise parameters of dough from both sets of samples. Keywords: wheat flour, malt flour, fermented dough, maturograph, oven rise recorder, bread volume Journal: Czech Journal of Food Sciences Pages: 210-218 Volume: 21 Issue: 6 Year: 2003 DOI: 10.17221/3500-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3500-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200306-0003.txt Handle: RePEc:caa:jnlcjf:v:21:y:2003:i:6:id:3500-CJFS Template-Type: ReDIF-Article 1.0 Author-Name: G. Karasová Author-Workplace-Name: G KARASOVÁ, E BRANDŠTETEROVÁ and M LACHOVÁ Author-Name: E. Branšteterová Author-Workplace-Name: G KARASOVÁ, E BRANDŠTETEROVÁ and M LACHOVÁ Author-Name: M. Lachová Author-Workplace-Name: G KARASOVÁ, E BRANDŠTETEROVÁ and M LACHOVÁ Title: Matrix solid phase dispersion as an effective preparation method for food samples and plants before HPLC analysis - a riview Abstract: This review deals with a preparation technique - Matrix Solid Phase Dispersion (MSPD) and its possibilities in the HPLC analysis for contaminants, pesticides, drug residues, and natural compounds in food samples. The main principle of MSPD is explained, the important factors influencing the effectivity and recovery of this technique are discussed. The advantages and disadvantages of MSPD and other classical extraction, isolation, and purifica­tion procedures are compared. The present article provides a bibliography of MSPD applications in food sample matrices during last years for various analytes and different sample matrices. Keywords: matrix solid phase dispersion, high performance liquid chromatography, food samples, contaminants, pesticides, drug residues, natural compounds Journal: Czech Journal of Food Sciences Pages: 219-234 Volume: 21 Issue: 6 Year: 2003 DOI: 10.17221/3501-CJFS File-URL: http://cjfs.agriculturejournals.cz/doi/10.17221/3501-CJFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/cjf-200306-0004.txt Handle: RePEc:caa:jnlcjf:v:21:y:2003:i:6:id:3501-CJFS