共查询到20条相似文献,搜索用时 15 毫秒
1.
Pressure-assisted thermal processing (PATP) inactivation kinetics of Bacillus amyloliquefaciens spores in deionized water (DIW) were evaluated for egg patty mince (EPM) and green pea puree (GPP). Recovery of PATP-injured spores during storage was determined. The number of B. amyloliquefaciens spores in DIW was reduced more than 6 log when treated at 121°C and 700 MPa, including a come-up time reduction (3.32 log MPN/g) and a pressure holding time reduction (3.55 log MPN/g). Treatments at 700 MPa in combination with 105°C for 16 min, 115°C for 5 min, or 121°C for 3 min, decreased B. amyloliquefaciens spore populations in EPM to levels undetectable using an enrichment procedure. No significant (p>0.05) recovery of PATP-injured spores was observed in EPM and GPP during storage for 8 weeks, compared with controls. These results provide useful information for enhancing microbial lethality of PATP-resistant bacterial spores in low-acid foods. 相似文献
2.
The use of pressure-assisted thermal processing (PATP) to inactivate bacterial spores in shelf-stable low-acid foods, without diminishing product quality, has received widespread industry interest. Egg patties were inoculated with Bacillus stearothermophilus spores (106 spores/g) and the product was packaged in sterile pouches by heat sealing. Test samples were preheated and then PATP-treated at 105 °C at various pressures and pressure-holding times. Thermal inactivation of spores was studied at 121 °C using custom-fabricated aluminum tubes; this treatment served as a control. Application of PATP at 700 MPa and 105 °C inactivated B. stearothermophilus spores, suspended in egg matrix rapidly, (4 log reductions in 5 min) when compared to thermal treatment at 121 °C (1.5 log reduction in 15 min). Spore inactivation by PATP progressed rapidly (3 log reductions at 700 MPa and 105 °C) during pressure-hold for up to 100 s, but greater holding times (up to 5 min) had comparatively limited effect. When PATP was applied to spores in water suspension or egg patties, D values were not significantly different. While thermal inactivation of spores followed first-order kinetics, PATP inactivation exhibited nonlinear inactivation kinetics. Among the nonlinear models tested, the Weibull model best described PATP inactivation of B. stearothermophilus spores in the egg product. 相似文献
3.
de Lamo-Castellví S Ratphitagsanti W Balasubramaniam VM Yousef AE 《Journal of food protection》2010,73(11):2043-2052
The aim of this research was to study the effect of sucrose laurate ester (SL) on enhancing pressure-assisted thermal processing (PATP) inactivation of Bacillus amyloliquefaciens Fad 82 spores. B. amyloliquefaciens spores (~10? CFU/ml) were suspended in deionized water, solutions of 0.1, 0.5, and 1.0% SL, and mashed carrots without or with 1% SL. Samples were treated at 700 MPa and 105°C for 0 (come-up time), 1, 2, and 5 min and analyzed by pour-plating and most-probable-number techniques. Heat shock (80°C, 10 min) was applied to untreated and treated samples to study the germination rates. Results were also compared against samples treated by high pressure processing (700 MPa, 35°C) and thermal processing (105°C, 0.1 MPa). Among the combinations tested, SL at concentrations of 1.0% showed the best synergistic effect against spores of B. amyloliquefaciens when combined with PATP treatments. In the case of high pressure and thermal processing treatments, SL did not enhance spore inactivation at the conditions tested. These results suggest that SL is a promising antimicrobial compound that can help reduce the severity of PATP treatments. 相似文献
4.
5.
研究了热压协同(500~600MPa,80-90℃)时嗜热脂肪芽孢杆菌芽孢在磷酸缓冲液和牛奶(经超高温灭菌)中灭活的动力学规律,并对超高静压的升压过程及相应的灭活效果进行了研究.结果表明,升压过程对嗜热脂肪芽孢杆菌芽孢灭活的影响不能忽略,且随压力增加这种效果越强,最高使其下降1.23个数量级;嗜热脂肪芽孢杆菌在牛奶中比在磷酸缓冲液中有更高的抗性;在3种拟合模型(线性、Weibull和Log-logistic模型)中,线性模型不适合模拟这些存活曲线,而Log-logistic模型能更好地模拟这些存活曲线,其次是Weibull模型. 相似文献
6.
7.
Low-temperature, long-time (LTLT) pasteurization assures the safety of banked human milk; however, heat can destroy important nutritional biomolecules. High-pressure processing (HPP) shows promise as an alternative for pasteurization of breast milk. The purpose of this study was to investigate the efficacy of HPP for inactivation of selected bacterial pathogens in human milk. Human milk was inoculated with one of five pathogens (10(8) to 10(9) CFU/ml), while 0.1% peptone solution solutions with the same levels of each organism were used as controls. The samples were subjected to 400 MPa at 21 to 31 degrees C for 0 to 50 min or to 62.5 degrees C for 0 to 30 min (capillary tube method) to simulate LTLT pasteurization. Tryptic soy agar and selective media were used for enumeration. Traditional thermal pasteurization resulted in inactivation (> 7 log) of all pathogens within 10 min. In human milk and in peptone solution, a 6-log reduction was achieved after 30 min of HPP for Staphylococcus aureus ATCC 6538. After 30 min, S. aureus ATCC 25923 was reduced by 8 log and 6 log in human milk and peptone solution, respectively. Treatments of 4 and 7 min resulted in an 8-log inactivation of Streptococcus agalactiae ATCC 12927 in human milk and peptone solution, respectively, while Listeria monocytogenes ATCC 19115 required 2 min for an 8-log inactivation in human milk. Escherichia coli ATCC 25922 was inactivated by 8 log after 10 min in peptone solution and by 6 log after 30 min in human milk. These data suggest that HPP may be a promising alternative for pasteurization of human milk. Further research should evaluate the efficacy of HPP in the inactivation of relevant viral pathogens. 相似文献
8.
The effects of high-pressure treatments at various temperature-time combinations on the inactivation of spores of Clostridium botulinum type A strains 62-A and BS-A in phosphate buffer (0.067 M, pH 7.0) and in a crabmeat blend were investigated. The log unit reduction of strain 62-A spores increased significantly as the processing pressure increased from 417 to 827 MPa (from 60,000 to 120,000 lb/in2) at 75 degrees C. The reduction of BS-A and 62-A spores in either medium increased as processing temperatures increased from 60 to 75 degrees C and processing times increased from 5 to 15 or 20 min at a maximum pressure of 827 MPa. Approximately 2- and 3-log reductions of BS-A and 62-A spores, respectively, in phosphate buffer were obtained at the maximum pressure-maximum temperature combination of 827 MPa and 75 degrees C for a processing time of 20 min. Processing for 15 min at the maximum pressure-maximum temperature combination resulted in maximum reductions of 3.2 and 2.7 log units for BS-A and 62-A spores, respectively, in the crabmeat blend. Results obtained in this study indicate that the crabmeat blend did not protect BS-A and 62-A spores against inactivation by high-pressure processing. 相似文献
9.
Kinetic parameters for the thermal inactivation of Geobacillus stearothermophilus ATCC 7953 and Bacillus flexus 1316 spores were determined for temperatures ranging from 100 to 130 °C and 100 to 125 °C, respectively. Ringer's solution (pH = 7.1) was used as the heating medium. A batch-heating system, in which the samples are kept in small tubes that are heated with steam, and a continuous-heating system, which is based upon a heat exchanger and enables high temperature short time heating, were used. Experiments were conducted in both systems and the heat resistances of the two species were determined. Additionally, a comparison of the two heating systems was carried out. The reaction rate constant at the reference temperature, kref, the activation energy, Ea, the D-value and the z-value were calculated for the two species. The D-values at 121 °C for G. stearothermophilus and for B. flexus in the batch-heating system were found to be 42 and 4.2 s, respectively. The z-values were calculated as 13 K for G. stearothermophilus and 16 K for B. flexus in the batch-heating system. The results from both systems differed significantly, wherein the continuous-heating system had been more lethal than the batch-heating system. 相似文献
10.
Paula María Periago P. S. Fernández María José Ocio A. Martínez 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1998,206(1):63-67
The effect of recovering Bacillus stearothermophilus spores under anaerobic conditions on their apparent thermal resistance was studied. Spores were suspended in bidistilled
water as a reference medium, heated at 115, 117, 119, 121, 123 and 125°C and recovered under aerobic and anaerobic conditions.
D values (decimal reduction time) obtained following recovery under anaerobic conditions were lower than those obtained under
aerobic conditions. Reductions of between 31 and 48% were found for all the temperatures studied. When spores were suspended
in mushroom extract and recovered under anaerobic conditions the apparent heat resistance was much lower than that obtained
under aerobic conditions (D
121°C was 4.3 min and 1.7 min, under aerobic and anaerobic conditions, respectively). Heating the spores in mushroom extract and
recovering the spores under anaerobic conditions produced an additive effect, decreasing the apparent heat resistance of the
B. stearothermophilus spores.
Received: 1 July 1997 相似文献
11.
Paula María Periago P. S. Fernández María José Ocio A. Martínez 《European Food Research and Technology》1998,206(1):63-67
The effect of recovering Bacillus stearothermophilus spores under anaerobic conditions on their apparent thermal resistance was studied. Spores were suspended in bidistilled water as a reference medium, heated at 115, 117, 119, 121, 123 and 125°C and recovered under aerobic and anaerobic conditions. D values (decimal reduction time) obtained following recovery under anaerobic conditions were lower than those obtained under aerobic conditions. Reductions of between 31 and 48% were found for all the temperatures studied. When spores were suspended in mushroom extract and recovered under anaerobic conditions the apparent heat resistance was much lower than that obtained under aerobic conditions (D 121°C was 4.3 min and 1.7 min, under aerobic and anaerobic conditions, respectively). Heating the spores in mushroom extract and recovering the spores under anaerobic conditions produced an additive effect, decreasing the apparent heat resistance of the B. stearothermophilus spores. 相似文献
12.
Non-thermal processed foods are generally cold stored and distributed. The use of ultrasound for food preservation has attracted the interest of many research groups. In the current study, the thermosonication (TS, simultaneous ultrasound and thermal process) inactivation of psychrotrophic Bacillus cereus spores was investigated (24 kHz, 210 μm, 0.33 W/mL or W/g). First, the effectiveness of a 1.5 min TS process at 70 °C in skim milk, beef slurry, cheese slurry, and rice porridge was investigated. The TS was more effective than sole thermal treatment in reducing B. cereus spores in rice porridge, beef slurry and cheese slurry by 7, 6, and 4 fold, respectively. Then, the first-order D- and z-values for TS and thermal processing in skim milk and beef slurry, and the best model to fit TS inactivation of B. cereus spores in beef slurry were determined. The D70 °C-values in skim milk were 2.9 min for TS and 8.6 min for the thermal treatment. And in beef slurry, values of 0.4 min for TS and 2.3 min for thermal were estimated. It was found that the Log-logistic model better described the TS spore inactivation in beef slurry. The ultrasound technology required 20–30 °C lower temperatures for the same spore inactivation, which resulted in better food quality and energy saving gains. 相似文献
13.
Anaerobic bacterial, clostridial, and Clostridium perfringens spores were enumerated in raw goose liver samples taken after evisceration of the birds (EB) in the slaughterhouse and after removal of blood vessels from the liver (RBVL) in the cannery. The samples taken after RBVL had significantly higher (P < 0.05) spore counts than did those taken after EB, indicating contamination of livers during processing. The number of C. perfringens spores was one log cycle higher in the samples taken after RBVL than in those taken after EB (P < 0.05). The confirmation of C. perfringens according to the profiles of Rapid ID 32 A tests was carried out by means of the ATB Plus computer program. With an identification percentage of 99.9 and a T-value of 0.65, the suspect colonies proved to be C. perfringens. Therefore, the importance of an appropriate cleaning and sanitation program and of personnel hygiene should be emphasized in the industry. 相似文献
14.
The combined effect of heat and hydrogen peroxide (HP) on the inactivation of avirulent Bacillus anthracis spores (Sterne strain 7702; strain ANR-1, an avirulent Ames derivative lacking the pXO2 plasmid; and strain 9131, a plasmid-less Sterne strain) was evaluated in milk. The study temperature ranged from 90 to 95 degrees C, and the concentration of added HP varied from 0.05 to 0.5%. Decimal reduction times (D-values) were determined using a sealed capillary tube technique. The mean D- and z-values of hydrated freeze-dried spores of all three strains in milk ranged from 550 s at 90 degrees C to 180 s at 94 degrees C and from 8.6 to 9.0 degrees C, respectively. When 0.05% HP was added to the milk, the D-values were decreased at least threefold, and at 0.5% HP the D-values ranged from 1 to 10 s. At 90 degrees C, all three strains had similar D-values when 0.05% HP was added. Increasing the concentration of HP to 0.5% had a greater reducing effect on the D-value for strain 7702 than on the values for strains ANR-1 and 9131. The rate of inactivation of each strain followed first-order reaction kinetics at each temperature-peroxide combination. Equations in the form of D = Constant x (HP concentration)n had R2 values greater than 0.97 for strains ANR-1 and 7702 and of at least 0.7 for strain 9131. This study suggests that a combination of high temperature (from 90 to 95 degrees C) and HP could be used for inactivation of B. anthracis spores in the event of deliberate contamination of milk such that the contaminated milk could be disposed of safely. 相似文献
15.
本文研究了高压二氧化碳(HPCD)对梨汁中细菌菌落总数的影响,并分析其杀菌动力学。结果表明:随着温度、压强升高以及处理时间延长,梨汁中细菌菌落总数显著降低(p<0.05);在相同温度和处理时间条件下,HPCD处理显著高于热处理的杀菌效果,处理温度对HPCD杀菌具有协同效应;当HPCD处理条件为30MPa、40℃、60min时,灭菌效果最佳,梨汁中细菌菌落总数的残存率降低了2.66个对数;Weibull模型能较好地拟合HPCD处理后梨汁中细菌菌落总数的失活曲线,模型动力学参数比例因子a和形状因子b随压力增加和温度升高呈现逐渐变小的规律性变化。 相似文献
16.
ABSTRACT: A kinetic model based on 2 irreversible serial chemical reactions has been proposed to fit experimental data of texture changes during thermal processing of potato products. The model links dimensionless maximum force F*MAX with processing time. Experimental texture changes were obtained during frying of French fries and potato chips at different temperatures, while literature data for blanching/cooking of potato cubes have been considered. A satisfactory agreement between experimental and predicted values was observed, with root mean square values (RMSs) in the range of 4.7% to 16.4% for French fries and 16.7% to 29.3% for potato chips. In the case of blanching/cooking, the proposed model gave RMSs in the range of 1.2% to 17.6%, much better than the 6.2% to 44.0% obtained with the traditional 1st-order kinetics. The model is able to predict likewise the transition from softening to hardening of the tissue during frying. 相似文献
17.
《International Dairy Journal》2005,15(6-9):777-784
Dairy companies commonly experience fermentation failures due to bacteriophages that are spread mainly by milk, whey or air. Heat or high-pressure treatment may potentially reduce the phage titre, but further knowledge about the inactivation kinetics is desirable. Inactivation experiments were carried out with the commonly occurring lactococcal phages P001 and P008. Phage suspensions in calcium-enriched M17-broth were heated at 55–80 °C, or high-pressure treated at up to 600 MPa. Kinetic analysis showed that the order of inactivation reaction was above 1; thus, inactivation kinetics were approximated by a non-linear regression model. The Arrhenius parameters, rate constant, kp,T, and activation energy, EA (for heat treatments), and the volume of activation, ΔV# (for pressure treatments) were calculated. Both measured and calculated results indicate that phage P008 was the more heat- and pressure-resistant of the two. By combining the results from heat and pressure inactivations, a pressure–temperature diagram for phage P008 was established. 相似文献
18.
Benjar Chutintrasri 《LWT》2007,40(2):300-306
Improvement of color, as a quality attribute of processed pineapple puree, has been made possible by the increase in knowledge of kinetic of color change. The kinetics of color degradation of pineapple puree were investigated during heat treatment at 70-110 °C in order to cover the temperature range that used in preheat and sterilization of commercial aseptic pineapple puree. Color changes associated with heat-treated puree were monitored using Hunter colorimeter (L, a, b, total color difference—ΔE) and Browning index (A420). The changes in L and b values fitted well to the first-order kinetic model while ΔE, a value, and Browning index followed the zero-order kinetic. The dependence of the rate constant on temperature was represented by an Arrhenius equation. The results suggested that ΔE and lightness, based on activation energy, were the most sensitive measures of color change at temperature range 70-90 and 95-110 °C, respectively. 相似文献
19.