Heat resistance and the effects of continuous pasteurization on the inactivation of Byssochlamys fulva ascospores in clarified apple juice

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)To determine thermal resistance, the effect of pasteurization temperature variations (c. 2 degrees C) in a continuous system in the number of decimal reductions (n) of a Byssochlamys strain in clarified apple juice (CAJ). Thermal destruction kinetics of Byssochlamys fulva IOC 4518 in thermal death tubes were determined at 85 degrees, 90 degrees, 92 degrees and 95 degrees C by using Weibull distribution frequency model. Three processes with different heating and holding temperatures (A: 94 degrees, 92 degrees C; B: 95 degrees, 93 degrees C; C: 96 degrees, 94 degrees C, respectively) were performed in a continuous system. Process time was 30 s. delta (time of first decimal reduction) values were: 42.98, 8.10, 3.62 and 1.81 min. Variable n ranged from 0.16 to > 4.78 for process B (equivalent to industrial). Variable n (0.95-2.66 log CFU ml(-1)) were obtained in CAJ bottles processed under condition B, while process A resulted in total heat-resistant mould (HRM) survival and process C in total HRM destruction. This study demonstrates that small variations in temperature during the CAJ pasteurization could result in elimination or survival of HRM due to its nonlogarithmic behaviour. This was the first study to use Weibull frequency method to model inactivation of HRM in fruit juices. Temperature variations could culminate in the presence of HRM in pasteurized juices even when low counts (< 10 spores per 100 ml) were present in the raw materials.1071197209Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundo de Apoio ao EnsaioPesquisa e a Extensao (Faepex) [282/06, 129/07]Prodetab (Embrapa) [042-01/01]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Pesquisa e a Extensao (Faepex) [282/06, 129/07]Prodetab (Embrapa) [042-01/01

Modelling the lag time and growth rate of Aspergillus section Nigri IOC 4573 in mango nectar as a function of temperature and pH

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Aims: To assess the behaviour of Aspergillus section Nigri IOC 4573 in mango nectar as affected by temperature and pH. Methods and Results: A central composite design (22 + 2*2 + 3) was used to estimate the influence of temperature (17 center dot 2-22 center dot 8 degrees C) and pH (3 center dot 28-4 center dot 7) on A. section Nigri growth (lambda, lag time; mu, growth rate). Secondary models (polynomial and Arrhenius-Davey) describing the effects of temperature and pH on lambda and mu were constructed. A decrease in temperature from 22 center dot 8 degrees C to 17 center dot 2 degrees C resulted in an a 16-fold increase in lambda. The increase in temperature from 20 degrees C to 22 center dot 8 degrees C at pH = 4 center dot 0 led to a fourfold increase in mu. The polynomial model was the best in fitting the data and the pH (linear), temperature (linear and quadratic terms) significantly influenced lambda. For mu, there was a significant influence by the pH (linear), temperature and pH (quadratic terms). Conclusions: The storage of mango nectar at < 15 degrees C and reduced pH could completely inhibit the growth of A. section Nigri. Significance and Impact of the Study: This is the first study to show how storage temperature and seasonal variability (pH) between harvests may affect mould growth in mango nectar.109311051116PRODETAB-EMBRAPA (Brazilian Agricultural Research Corporation)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Risk of infection with Salmonella and Listeria monocytogenes due to consumption of ready-to-eat leafy vegetables in Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The current study was carried out to estimate the risks of infection due to consumption of RTE vegetables contaminated with Salmonella and Listeria monocytogenes in Brazil. The risk assessment model was composed of five different modules comprising the retail-consumption steps. Scenarios were simulated using prevalence and concentration levels reported in RTE vegetables in Brazil as well as considering values 10 times lower. In addition, scenarios in which temperature during transportation and storage are maintained below 5 degrees C were also evaluated. Models built in Excel spreadsheets were run (100,000 iterations) using @Risk software. The two outputs were risk of infection per month (probability of infection per month due to consumption of RTE vegetables) and number of infections per month (number of people that consumed RTE vegetables and get infected per month). The QMRA models predicted that the mean risk of Salmonella infection per month is 5.7E-03, while the mean risk of infection for L. monocytogenes was 8.1E-06 per month. The reduction of prevalence of Salmonella from 1.7% to 0.17% resulted in a decrease of risk of infection per month by about 6 times. In the case of L monocytogenes, the reduction of prevalence from 2.2% to 0.22% resulted in decrease of risk of infection from 8.1E-06 to 1.0E-06. The risks and number of cases predicted in scenarios in which temperature was kept below 5 degrees C were reduced for both pathogens studied when compared to scenarios where this was not the case. The scenario where prevalence and concentration of pathogens was reduced and where temperature was <5 degrees C led to the lowest number of infections due by Salmonella and L. monocytogenes (187 and 3.3E-05 cases, respectively). The results suggest that effective mitigation strategies need to be adopted. The strict control of temperature during transportation, storage and consumption was more effective to reduce risk and number of cases due to L. monocytogenes than to Salmonella. More data is needed to improve the accuracy of risk assessment models developed. (C) 2014 Elsevier Ltd. All rights reserved.4218Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [07/54891-2, 07/54890-6]CAPES [0241-10-5

Alicyclobacillus acidoterrestris in pasteurized exotic Brazilian fruit juices: Isolation, genotypic characterization and heat resistance

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)In this study, the population of Alicyclobacillus spp. was estimated in pasteurized exotic Brazilian fruit juices using the most probable number (MPN) technique followed by biochemical tests. Pasteurized passion fruit (n = 57) and pineapple (n = 50) juices were taken directly from Brazilian manufacturers. While Alicyclobacillus spp. was isolated from passion fruit juice, the microorganism was not found in any pineapple juice samples. A higher incidence of Alicyclobacillus was observed in samples taken in June and July (dry months in Brazil) in comparison to the other months (March, April, May and August), and the highest Alicyclobacillus counts were recovered from these samples(>23 MNP/100 mL). Sixteen (n = 16) Alicyclobacillus strains were typed using the randomly amplified polymorphic DNA method (RAPD-PCR). RAPD-PCR revealed great genetic similarity between the passion fruit juice strains and Alicyclobacillus acidoterrestris DSM 2498. The heat resistance of three isolates was determined, and the mean D(95)degrees. (1.7 min) and z (7.6 degrees C) values in the passion fruit juice were not significantly different (p > 0.05) from those obtained for the DSM 2498 strain (D(95)degrees = 1.5 min and z = 7.1 degrees C). This is the first report on the isolation of A. acidoterrestris from exotic fruit juices such as passion fruit juice. It is worth pointing out the importance of applying good agricultural practices in the field and applying controls for the fruit selection and washing steps, as well as controlling the time/temperature conditions for pasteurization so as to reduce the incidence and chances of A. acidoterrestris spoilage in these juices. (C) 2010 Elsevier Ltd. All rights reserved.27810161022Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Influence of the hot-fill water-spray-cooling process after continuous pasteurization on the number of decimal reductions and on Alicyclobacillus addoterrestris CRA 7152 growth in orange juice stored at 35 degrees C

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)In this study, the influence of the hot-fill water-spray-cooling process after continuous pasteurization on the number of decimal reductions (gamma) and growth parameters (lag time; lambda, ratio N-f/N-o; kappa, maximum growth rate; mu) of Alicyclobacillus acidoterrestris CRA 7152 in orange juice stored at 35 degrees C were investigated. Two different inoculum levels of A acidoterrestris CRA 7152 (102 and 103 spores/mL) in orange juice (11(0)Brix, pH 3.7) and a Microthermics UHT-HTST pilot plant were used to simulate industrial conditions. Results have shown that regardless of the inoculum level (10(2) or 10(3) spores/mL). the pasteurization processes were unable to cause even 1 gamma. Predictive modeling using the Baranyi model showed that only kappa and time to reach 10(4) spores/mL (t10(4) - time to juice spoilage) were affected by the spore inoculum used (p<0.05). It has been concluded that A. acidoterrestris was able to survive the hot-fill process and to grow and spoil orange juice in 5-6 days when the final storage temperature was 35 degrees C. (C) 2009 Elsevier B.V. All rights reserved.13741700295298Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq