The Experts below are selected from a list of 4068 Experts worldwide ranked by ideXlab platform
Fabienne Remize - One of the best experts on this subject based on the ideXlab platform.
-
Contamination pathways of spore-forming bacteria in a vegetable cannery
International Journal of Food Microbiology, 2015Co-Authors: Loïc Durand, Stella Planchon, Marie-hélène Guinebretière, Stéphane André, Frederic Carlin, Fabienne RemizeAbstract:Spoilage of low-acid Canned Food during prolonged storage at high temperatures is caused by heat resistant thermophilic spores of strict or facultative bacteria. Here, we performed a bacterial survey over two consecutive years on the processing line of a French company manufacturing Canned mixed green peas and carrots. In total, 341 samples were collected, including raw vegetables, green peas and carrots at different steps of processing, cover brine, and process environment samples. Thermophilic and highly-heat-resistant thermophilic spores growing anaerobically were counted. During vegetable preparation, anaerobic spore counts were significantly decreased, and tended to remain unchanged further downstream in the process. Large variation of spore levels in products immediately before the sterilization process could be explained by occasionally high spore levels on surfaces and in debris of vegetable combined with long residence times in conditions suitable for growth and sporulation. Vegetable processing was also associated with an increase in the prevalence of highly-heat-resistant species, probably due to cross-contamination of peas via blanching water. Geobacillus stearothermophilus M13-PCR genotypic profiling on 112 isolates determined 23 profile-types and confirmed process-driven cross-contamination. Taken together, these findings clarify the scheme of contamination pathway by thermophilic spore-forming bacteria in a vegetable cannery.
-
thermophilic spore forming bacteria isolated from spoiled Canned Food and their heat resistance results of a french ten year survey
International Journal of Food Microbiology, 2013Co-Authors: Stéphane André, Francois Zuber, Fabienne RemizeAbstract:Abstract Thermal processing of Low Acid Canned Foods (LACF), which are safe and shelf-stable at ambient temperature for several years, results in heat inactivation of all vegetative microorganisms and the partial or total inactivation of spores. Good Manufacturing Hygienic Practices include stability tests for managing the pathogen risk related to surviving mesophilic bacterial spores. LACF are also often submitted to additional incubation conditions, typically 55 °C for 7 days, to monitor spoilage by thermophiles. In this study we identified the bacterial species responsible for non-stability after prolonged at 55 °C of incubation of LACF from 455 samples collected from 122 French canneries over 10 years. Bacteria were identified by microsequencing or a recent developed tool for group-specific PCR detection (SporeTraQ™). A single species was identified for 93% of examined samples. Three genera were responsible for more than 80% of all non-stability cases: mostly Moorella (36%) and Geobacillus (35%), and less frequently Thermoanaerobacterium (10%). The other most frequent bacterial genera identified were Bacillus, Thermoanaerobacter, Caldanaerobius, Anoxybacillus, Paenibacillus and Clostridium. Species frequency was dependent on Food category, i.e. vegetables, ready-made meals containing meat, seaFood or other recipes, products containing fatty duck, and related to the intensity of the thermal treatment applied in these Food categories. The spore heat resistance parameters (D or δ and z values) from 36 strains isolated in this study were determined. Taken together, our results single out the species most suitable for use as indicators for thermal process settings. This extensively-documented survey of the species that cause non-stability at 55 °C in LACF will help canneries to improve the management of microbial contamination.
-
Prevalence of Clostridium botulinum and thermophilic heat-resistant spores in raw carrots and green beans used in French canning industry
International Journal of Food Microbiology, 2012Co-Authors: V. Sevenier, Stéphane André, Sandrine Delannoy, P. Fach, Fabienne RemizeAbstract:Two categories of vegetables (carrots and green beans) that are widely used in the manufacture of Canned Food were surveyed for their spore contamination. Samples were recovered from 10 manufactures spread over all producing areas in France. Two samples over 316 raw vegetables collected were found positive for botulinum neurotoxin producing Clostridia spores as tested by PCR-based GeneDisc assay. Both positive samples tested positive for the type B neurotoxin gene (bont/B). In parallel, heat-resistant spores of thermophilic bacteria that are likely to be associated with Canned Food spoilage after prolonged incubation at 55 degrees C were surveyed after specific enrichment. Prevalence varied between 1.6% for Moorella thermoacetica/thermoautotrophica in green bean samples and 8.6% for either Geobacillus stearothermophilus or Thermoanaerobacterium spp. in carrot samples. Vegetable preparation, e.g. washing and edge cutting, considerably reduced spore contamination levels. These data constitute the first wide examination of vegetables specifically cultivated for industrial purposes for their contamination by spores of thermophilic bacterial species. (C) 2012 Elsevier B.V. All rights reserved.
-
pcr detection of thermophilic spore forming bacteria involved in Canned Food spoilage
Current Microbiology, 2010Co-Authors: S Prevost, Stéphane André, Fabienne RemizeAbstract:Thermophilic bacteria that form highly heat-resistant spores constitute an important group of spoilage bacteria of low-acid Canned Food. A PCR assay was developed in order to rapidly trace these bacteria. Three PCR primer pairs were designed from rRNA gene sequences. These primers were evaluated for the specificity and the sensitivity of detection. Two primer pairs allowed detection at the species level of Geobacillus stearothermophilus and Moorella thermoacetica/thermoautrophica. The other pair allowed group-specific detection of anaerobic thermophilic bacteria of the genera Thermoanaerobacterium, Thermoanaerobacter, Caldanerobium and Caldanaerobacter. After a single enrichment step, these PCR assays allowed the detection of 28 thermophiles from 34 cans of spoiled low-acid Food. In addition, 13 ingredients were screened for the presence of these bacteria. This PCR assay serves as a detection method for strains able to spoil low-acid Canned Food treated at 55°C. It will lead to better reactivity in the canning industry. Raw materials and ingredients might be qualified not only for quantitative spore contamination, but also for qualitative contamination by highly heat-resistant spores.
A Abdul G Ghani - One of the best experts on this subject based on the ideXlab platform.
-
a new computational technique for the estimation of sterilization time in Canned Food
Chemical Engineering and Processing, 2004Co-Authors: Mohammed M Farid, A Abdul G GhaniAbstract:Sterilization of liquid Food in cans is complicated by the influence of natural convection currents induced by the hot walls of the can. In order to predict the temperature variation of the slowest heating zone (SHZ) with time, it is necessary to use computational fluid dynamics (CFD) analysis, which can be done with the help of a number of available commercial software. However, the required computational time is usually of the order of hours. In this paper, simple method of calculation is developed to predict the SHZ without the requirement of sophisticated computations. A generalized correlation was developed to predict the change of the SHZ with time for different fluids and can sizes.
-
thermal sterilization of Canned Food in a 3 d pouch using computational fluid dynamics
Journal of Food Engineering, 2001Co-Authors: A Abdul G Ghani, Mohammed M Farid, Xiao Dong Chen, P J RichardsAbstract:Abstract Sterilization of Food in cans has been well studied both experimentally and theoretically, but little or no work has been done on sterilization of Food in pouches. The Food pouches have only been recently introduced to the market. In this study, transient temperature, velocity profiles and the shape of the slowest heating zone (SHZ) have been established for a uniformly heated three-dimensional pouch containing carrot–orange soup, using saturated steam at 121°C. The computational fluid dynamics (CFD) code PHOENICS was used for this purpose. The liquid Food used in the simulation has temperature-dependent viscosity and density. From the simulations, the maximum axial velocity of the soup was found to be 10 −2 −10 −4 mm s −1 , which was due to the small height of the pouch and high viscosity of the soup. The SHZ was found to migrate into a region within 30–40% of the pouch height above the bottom and at a distance approximately 20–30% of the pouch length from its widest end. The experimental measurements were conducted at Heinz Watties Australasia based in New Zealand. The measured temperature at different locations in the pouch was compared with that predicted. Both results were found to be in good agreement. The results of a simulation done for the same pouch geometry and material considering pure conduction mechanism were also presented for the purpose of comparison.
-
numerical simulation of natural convection heating of Canned Food by computational fluid dynamics
Journal of Food Engineering, 1999Co-Authors: A Abdul G Ghani, Mohammed M Farid, Xiao Dong Chen, P J RichardsAbstract:Abstract Natural convection heating within a can of liquid Food during sterilization is simulated by solving the governing equations for continuity, momentum and energy conservation for an axisymmetric case using a commercial Computational Fluid Dynamics (CFD) package ( PHOENICS ). Transient flow patterns and temperature profiles within model liquids (sodium carboxy-methyl cellulose (CMC) and water) have been predicted. The model liquids, CMC and water, were assumed to have constant properties except for the viscosity (temperature dependent) and density (Boussinesq approximation). It has been shown that the action of natural convection forces the slowest heating zone (SHZ) to migrate towards the bottom of the can as expected. The shape and the size of the SHZ area are different for CMC and water. The magnitude of the axial velocity was found to be in the range of 10 −5 –10 −4 m/s for CMS and of 10 −2 –10 −1 m/s for water, these magnitudes of course vary with time and position in the can. The time required for the SHZ to reach the sterilization temperature of 100°C was 1800 s for CMC and only, 150 s for water.
P J Richards - One of the best experts on this subject based on the ideXlab platform.
-
thermal sterilization of Canned Food in a 3 d pouch using computational fluid dynamics
Journal of Food Engineering, 2001Co-Authors: A Abdul G Ghani, Mohammed M Farid, Xiao Dong Chen, P J RichardsAbstract:Abstract Sterilization of Food in cans has been well studied both experimentally and theoretically, but little or no work has been done on sterilization of Food in pouches. The Food pouches have only been recently introduced to the market. In this study, transient temperature, velocity profiles and the shape of the slowest heating zone (SHZ) have been established for a uniformly heated three-dimensional pouch containing carrot–orange soup, using saturated steam at 121°C. The computational fluid dynamics (CFD) code PHOENICS was used for this purpose. The liquid Food used in the simulation has temperature-dependent viscosity and density. From the simulations, the maximum axial velocity of the soup was found to be 10 −2 −10 −4 mm s −1 , which was due to the small height of the pouch and high viscosity of the soup. The SHZ was found to migrate into a region within 30–40% of the pouch height above the bottom and at a distance approximately 20–30% of the pouch length from its widest end. The experimental measurements were conducted at Heinz Watties Australasia based in New Zealand. The measured temperature at different locations in the pouch was compared with that predicted. Both results were found to be in good agreement. The results of a simulation done for the same pouch geometry and material considering pure conduction mechanism were also presented for the purpose of comparison.
-
numerical simulation of natural convection heating of Canned Food by computational fluid dynamics
Journal of Food Engineering, 1999Co-Authors: A Abdul G Ghani, Mohammed M Farid, Xiao Dong Chen, P J RichardsAbstract:Abstract Natural convection heating within a can of liquid Food during sterilization is simulated by solving the governing equations for continuity, momentum and energy conservation for an axisymmetric case using a commercial Computational Fluid Dynamics (CFD) package ( PHOENICS ). Transient flow patterns and temperature profiles within model liquids (sodium carboxy-methyl cellulose (CMC) and water) have been predicted. The model liquids, CMC and water, were assumed to have constant properties except for the viscosity (temperature dependent) and density (Boussinesq approximation). It has been shown that the action of natural convection forces the slowest heating zone (SHZ) to migrate towards the bottom of the can as expected. The shape and the size of the SHZ area are different for CMC and water. The magnitude of the axial velocity was found to be in the range of 10 −5 –10 −4 m/s for CMS and of 10 −2 –10 −1 m/s for water, these magnitudes of course vary with time and position in the can. The time required for the SHZ to reach the sterilization temperature of 100°C was 1800 s for CMC and only, 150 s for water.
A Kannan - One of the best experts on this subject based on the ideXlab platform.
-
heat transfer analysis of Canned Food sterilization in a still retort
Journal of Food Engineering, 2008Co-Authors: A Kannan, Ch Gourisankar P SandakaAbstract:Computational fluid dynamics (CFD) analyses provide insight on the natural convective processes occurring during the sterilization of Canned liquid Food. The definition and estimation of heat transfer coefficients pertaining to the transient heat transfer occurring in cylindrical Food cans is presented. The heat transfer coefficients defined on the basis of absolute mass flow averaged and volume-averaged temperatures are compared. The contributions to the overall heat transfer rate from different surfaces of the uniformly heated cylindrical can are evaluated. The influence of the temperature difference to viscosity ratio on the peculiar Nusselt number trends is discussed. Unified correlations are provided for the Nusselt number as functions of Fourier number, Food can aspect ratio and thermal conductivity of the Food medium in both the conduction and convection dominated heat transfer regimes.
-
cfd studies on natural convective heating of Canned Food in conical and cylindrical containers
Journal of Food Engineering, 2006Co-Authors: Mahesh N Varma, A KannanAbstract:Enhancing natural convective heat transfer in Canned Food sterilization is explored through modifications to container geometry and its orientation. A conical geometry, of equal volume and height as that of the cylinder, pointing either vertically up or down was considered. The non-Newtonian fluid, 0.85% w/w sodium carboxy-methyl cellulose (CMC), was taken as the test Food material and its laminar flow behavior was investigated using computational fluid dynamics (CFD). The movement of the slowest heating zone (SHZ) temperature was tracked and compared for the three geometries. The SHZ temperature was observed to attain the final sterilization fluid temperature of 100 °C fastest for an upright conical geometry followed by the cylinder and the downward pointing cone. There is scope for enhancing the thermal sterilization process through geometry modifications but without mechanical agitation or rotation. Further, the geometry modification if non-uniform must be complemented by its suitable orientation.
Hosahalli S Ramaswamy - One of the best experts on this subject based on the ideXlab platform.
-
effect of reciprocating agitation thermal processing ra tp on quality of Canned tomato solanum lycopersicum puree
Journal of the Science of Food and Agriculture, 2017Co-Authors: Anubhav Pratap Singh, Anika Singh, Hosahalli S RamaswamyAbstract:Reciprocating agitation thermal processing (RA-TP) is a recent innovation in the field of canning for obtaining high-quality Canned Food. The objective of this study was to compare RA-TP processing with conventional non-agitated (still) processing with respect to the impact on quality (color, antioxidant capacity, total phenols, carotenoid and lycopene contents) of Canned tomato (Solanum lycopersicum) puree.Owing to a 63-81% reduction in process times as compared with still processing, tomato puree with a brighter red color (closer to fresh) was obtained during RA-TP. At 3 Hz reciprocation frequency, the loss of antioxidant, lycopene and carotenoid contents could be reduced to 34, 8 and 8% respectively as compared with 96, 41 and 52% respectively during still processing. In fact, the phenolic content for RA-TP at 3 Hz was 5% higher than in fresh puree. Quality retention generally increased with an increase in frequency, although the differences were less significant at higher reciprocation frequencies (between 2 and 3 Hz).Research findings indicate that RA-TP can be effective to obtain thermally processed Foods with high-quality attribute retention. It can also be concluded that a very high reciprocation frequency (>3 Hz) is not necessarily needed and significant quality improvement can be obtained at lower frequencies (∼2 Hz). © 2016 Society of Chemical Industry.
-
effect of reciprocating agitation thermal processing ra tp on quality of Canned tomato puree solanum lycopersicum
Journal of the Science of Food and Agriculture, 2016Co-Authors: Anubhav Pratap Singh, Anika Singh, Hosahalli S RamaswamyAbstract:BACKGROUND Reciprocating agitation thermal processing (RA-TP) is a recent innovation in the field of canning for obtaining high quality Canned Food. The objective of this study is to compare RA-TP processing with conventional non-agitated (still) processing with respect to the impact on quality (color, antioxidant capacity, total phenols, carotenoid and lycopene content) of Canned tomato (Solanum lycopersicum) puree. RESULTS Due to 63-81% reduction in process times as compared to still process, tomato puree with a brighter red color (closer to fresh) was obtained during RA-TP. At 3 Hz reciprocation frequency, the loss in antioxidant, lycopene and carotenoid contents could be reduced to 34%, 8% and 8% respectively, as compared to 96%, 41% and 52%, respectively during still process. In fact, the phenolic content for RA-TP at 3 Hz was 5% higher than in fresh puree. Quality retention generally increased with an increase in frequency, although the differences were less significant at higher reciprocation frequencies (between 2 Hz and 3 Hz). CONCLUSIONS Research findings indicate that RA-TP can be effective to obtain thermally processed Foods with high quality attribute retention. It can also be concluded that a very high reciprocation frequency (>3Hz) is not necessarily needed and significant quality improvement can be obtained at lower frequencies (~2Hz).
