ABSTRACT
BACKGROUND: Acute exercise is one factor that increases blood homocysteine levels, and elevated homocysteine levels cause oxidative stress. Albumin, which is abundant in blood, is an antioxidant, and the redox state of albumin is used as an index of oxidative stress in blood. This study aimed to assess the effect of acute exercise on plasma homocysteine levels and the blood non-mercaptoalbumin/mercaptoalbumin ratio as an oxidative stress marker. METHODS: This study used a crossover design with exercise and control conditions. Under exercise conditions, a bicycle ergometer was used to perform 40 min of transient constant-load exercise at 65% heart rate reserve. Under control conditions, participants rested for 40 min. Blood was collected before, 30 min after, and 90 min after exercise, and at the same time points under control conditions. Samples were analyzed for the homocysteine concentration and non-mercaptoalbumin/mercaptoalbumin ratio. RESULTS: The results revealed that a 65% heart rate reserve and 40 min of acute exercise increased plasma homocysteine concentration and non-mercaptoalbumin ratio. In the intra-condition comparison, the plasma Hcy concentration was significantly increased at Post 30 min (+ 0.83 ± 0.70 µmol/L, P = 0.003) compared with that at Pre in the exercise condition. Furthermore, 90 min after exercise, the blood non-mercaptoalbumin ratio was significantly increased (+ 0.35 ± 0.71%, P = 0.030) compared to Pre. CONCLUSION: These results indicate that the plasma Hcy concentration first increased, and then the non-mercaptoalbumin/mercaptoalbumin ratio increased as the elevated state was maintained. This study revealed that 65% heart rate reserve, 40 min of acute exercise increased plasma Hcy concentration and non-mercaptoalbumin ratio.
ABSTRACT
BACKGROUND: The CompactDry "Nissui" BC is a ready-to-use dry media sheet using a chromogenic medium with selective agents for the detection and enumeration of Bacillus cereus in products after incubation at 30 ± 1°C for 24 ± 2 h. OBJECTIVE: The CompactDry "Nissui" BC method was validated to achieve AOAC Performance Tested MethodsSM certification. METHOD: The performance of the CompactDry "Nissui" BC was compared to that of ISO 7932:2004 for 10 matrixes, including panna cotta, double cream, dried baby food, dried vegetable soup mix, seafood sticks, salmon pâté, sliced ham, pork liver pâté, ham and cheese sandwich, and Caesar pasta salad with chicken and bacon. Performance indicators included repeatability, difference of means (DOM), and inclusivity/exclusivity. RESULTS: After log10 transformation of the data, the relative standard deviation of repeatability (RSDr) was ≤9.2% for 28 of the 30 materials (10 matrixes each at three contamination levels) analyzed by the CompactDry "Nissui" BC method and ≤13% for 27 of the 30 matrix/level combinations analyzed by the reference method. Method equivalence was demonstrated in 28 of the 30 matrix/level combinations based on the 90% confidence interval of the DOM being within (-0.5, 0.5). For inclusivity, 47 of 50 strains tested showed typical colonies and confirmed positive. For exclusivity, 28 of 33 strains tested resulted in no growth or were negative, and five were positive. Inclusivity and exclusivity results were similar on the reference method agar. The method was shown to be robust to changes in sample volume, incubation temperature, and incubation time, and data are presented supporting product consistency and 18-month shelf life. CONCLUSIONS: The CompactDry "Nissui" BC method is validated for the determination of Bacillus cereus in a variety of matrixes. HIGHLIGHTS: The CompactDry "Nissui" BC method is equivalent to the ISO 7932:2004 reference method and is suitable for Performance Tested MethodsSM certification for the matrixes tested.
Subject(s)
Bacillus cereus , Food Microbiology , Agar , Infant Food , SeafoodABSTRACT
BACKGROUND: CompactDry™ "Nissui" TCR are ready-to-use dry media sheets using a chromogenic medium for the enumeration of mesophilic aerobic bacteria in foods in as little as 24 h. OBJECTIVE: The CompactDry "Nissui" TCR method was validated to achieve AOAC Performance Tested MethodsSM certification. METHOD: The performance of the CompactDry "Nissui" TCR was compared to that of USDA/FSIS MLG 3.02, FDA BAM Chapter 3, and SMEDP Chapter 6 for 11 matrixes. All 11 matrixes were tested by CompactDry incubation at 35 ± 1°C for 24 ± 2 and 48 ± 3 h. The three dairy matrixes were also evaluated by CompactDry incubation at 32 ± 1°C for 24 ± 2 and 48 ± 3 h and additionally at 72 ± 3 h for nonfat dry milk. RESULTS: After log10 transformation of the data, the standard deviation of repeatability (sr) was similar between CompactDry "Nissui" TCR and the respective reference methods, and method equivalence based on the 90% confidence interval of the difference of means being within (-0.5, 0.5) was demonstrated for all matrixes, incubation temperatures, and incubation times in the method developer and independent laboratory studies. The method was shown to be robust, and data are presented supporting product consistency and 18-month shelf life. CONCLUSIONS: The CompactDry "Nissui" TCR method was validated for the determination of mesophilic aerobic bacteria in a variety of matrixes with incubation at 35 ± 1°C for 24 ± 2 and 48 ± 3 h and for dairy matrixes also at 32 ± 1°C for 24 ± 2, 48 ± 3, and 72 ± 3 h. HIGHLIGHTS: The CompactDry "Nissui" TCR method is equivalent to the USDA/FSIS MLG 3.02, FDA BAM Chapter 3, and SMEDP Chapter 6 reference methods and is suitable for Performance Tested MethodsSM certification for the matrixes tested.
