Growth of Listeria spp. in Shredded Cabbage Is Enhanced by a Mild Heat Treatment

2010 ◽  
Vol 73 (3) ◽  
pp. 425-433 ◽  
Author(s):  
TIMOTHY C. ELLS ◽  
LISBETH TRUELSTRUP HANSEN
Keyword(s):  
Thermal Processing ◽  
Fruits And Vegetables ◽  
Storage Period ◽  
Thermal Treatments ◽  
Organoleptic Properties ◽  
Maximum Increase ◽  
Safety Issues ◽  
Heat Treated ◽  
Survival And Growth ◽  
Growth Inhibiting

Mild thermal processing can enhance the shelf life of cut fruits and vegetables by delaying the onset of spoilage and preserving the organoleptic properties of shredded cabbage. However, food safety issues related to this process have not been fully investigated. Therefore, the survival and growth of Listeria spp. on cabbage treated in this manner was examined. Experimentally, 24 strains of Listeria spp. (including L. monocytogenes) were inoculated onto cut and intact cabbage tissues and stored at 5°C. All strains on intact tissues exhibited a moderate decline in numbers (up to 1.0 log CFU/cm2) over the 28-day storage period. Conversely, cut tissue supported growth of most strains during the first 7 to 14 days of incubation with maximum increases of 1.2 log CFU/cm2. Subsequently, the survival or growth on heat-treated (50°C for 3 min) and untreated shredded cabbage of four L. monocytogenes and four nonpathogenic Listeria spp. strains were compared during storage for 21 days at 5°C. Growth on untreated shred for all strains was similar to the results observed on cut tissue with a maximum increase of approximately 1.0 log CFU/g. However, in the heat-treated cabbage shred all strains displayed a rapid increase in growth (up to 2.5 log CFU/g) during the first 7 days of incubation, which may be indicative of the destruction of an endogenous growth-inhibiting compound within the cabbage. In conclusion, this study shows that mild thermal treatments of cut cabbage may promote pathogen growth if other inimical barriers are not implemented downstream of the thermal treatment.

scholarly journals Spatiotemporal Visualization of Insecticides and Fungicides within Fruits and Vegetables Using Gold Nanoparticle-Immersed Paper Imprinting Mass Spectrometry Imaging

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1327
Author(s):  
Run Qin ◽  
Ping Li ◽  
Mingyi Du ◽  
Lianlian Ma ◽  
Yudi Huang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Food Safety ◽  
Gold Nanoparticle ◽  
Pesticide Residue ◽  
Rational Design ◽  
Mass Spectrometry Imaging ◽  
Fruits And Vegetables ◽  
Detection Methods ◽  
Safety Issues ◽  
Spatiotemporal Visualization

Food safety issues caused by pesticide residue have exerted far-reaching impacts on human daily life, yet the available detection methods normally focus on surface residue rather than pesticide penetration to the internal area of foods. Herein, we demonstrated gold nanoparticle (AuNP)-immersed paper imprinting mass spectrometry imaging (MSI) for monitoring pesticide migration behaviors in various fruits and vegetables (i.e., apple, cucumber, pepper, plum, carrot, and strawberry). By manually stamping food tissues onto AuNP-immersed paper, this method affords the spatiotemporal visualization of insecticides and fungicides within fruits and vegetables, avoiding tedious and time-consuming sample preparation. Using the established MSI platform, we can track the migration of insecticides and fungicides into the inner region of foods. The results revealed that both the octanol-water partition coefficient of pesticides and water content of garden stuffs could influence the discrepancy in the migration speed of pesticides into food kernels. Taken together, this nanopaper imprinting MSI is poised to be a powerful tool because of its simplicity, rapidity, and easy operation, offering the potential to facilitate further applications in food analysis. Moreover, new perspectives are given to provide guidelines for the rational design of novel pesticide candidates, reducing the risk of food safety issues caused by pesticide residue.

Analysis of a Renewable Energy Based System Using Nanofluids for Power Generation

2016 ◽  
Author(s):  
Adnan Alashkar ◽  
Mohamed Gadalla
Keyword(s):  
Power Generation ◽  
Storage System ◽  
Storage Period ◽  
Rankine Cycle ◽  
Energy Storage System ◽  
Energy Output ◽  
Conventional Heating ◽  
Maximum Increase ◽  
Levelized Cost Of Electricity ◽  
Modes Of Operation

In this present paper, a performance analysis of an Integrated Solar Rankine Cycle (ISRC) is provided. The ISRC consists of a nanofluid-based Parabolic Trough Solar Collector (PTSC), and a Thermal Energy Storage System (TES) integrated with a Rankine Cycle. The effect of dispersing Copper (Cu) nanoparticles in a conventional heating fluid (Syltherm 800) on the output performance and cost of the ISRC is studied for different volume fractions, and for two modes of operation. The first mode assumes no storage, while the second assumes a storage system with a storage period of 7 hours. For the second mode of operation, the charging and discharging cycles are explained. The results show that the presence of the nanoparticles causes an increase in the overall energy produced by the ISRC for both modes of operation, and also causes a decrease in the Levelized Cost of Electricity (LEC), and an increase in the net savings of the ISRC. When comparing the two modes of operation it is established that the existence of a storage system leads to a higher power generation, and a lower LEC; however the efficiency of the cycle drops. It is seen that the maximum increase in the annual energy output of the ISRC caused by the addition of the nanoparticles is around 3.5%, while the maximum increase in the net savings is around 12.8%.

scholarly journals Immunoreactivity of Lupine and Soybean Allergens in Foods as Affected by Thermal Processing

Foods ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 254 ◽  
Author(s):  
Caterina Villa ◽  
Mónica B. M. V. Moura ◽  
Joana Costa ◽  
Isabel Mafra
Keyword(s):  
Trypsin Inhibitor ◽  
Thermal Processing ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Meat Products ◽  
Soybean Trypsin Inhibitor ◽  
Thermal Treatments ◽  
Food Matrix ◽  
Soybean Proteins ◽  
Sds Page

Lupine and soybean are important technological aids for the food industry. However, they are also capable of inducing severe allergic reactions in food-sensitized/allergic individuals. In this context, this work intended to study the combined effects of thermal processing and food matrix on the immunoreactivity of lupine and soybean proteins used as ingredients in bakery and meat products, respectively. For this purpose, the effects of baking, mild oven cooking, and autoclaving on the protein profiles were evaluated, using model mixtures simulating the production of lupine-containing breads and soybean-containing cooked hams/sausages, by native- and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and immunoblotting using specific antibodies. The results showed that lupine gamma-conglutin immunoreactivity was slightly decreased in wheat flour mixtures compared to rice, but it was more pronounced in baked products. In meat mixtures, substantial protein fragmentation was noted after autoclaving, with decreased immunoreactivity of soybean trypsin inhibitor. The analysis of 22 commercial products enabled the identification of lupine gamma-conglutin in four bakery samples and soybean trypsin-inhibitor in five sausages, and further differentiated autoclaved from other milder thermally treated products. Generally, the immunoreactivity of target proteins was reduced by all the tested thermal treatments, though at a higher extent after autoclaving, being slightly altered by the food matrix.

scholarly journals Influencing Factors and Control Strategies of Heat Treatment Deformation of Metal Materials

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Qiang Li ◽  
Yutao Wang
Keyword(s):  
Heat Treatment ◽  
Influencing Factors ◽  
Thermal Processing ◽  
Control Strategies ◽  
Mechanical Parts ◽  
Performance Requirements ◽  
Heat Treated ◽  
Metal Materials ◽  
And Control

In the thermal processing of metal materials, the performance of thematerial is more stable, and the heat-treated materials are processed into parts to make the performance more excellent and more in line with the performance requirements of mechanical parts. However, in thermal processing, metal materials are prone to problems, such as deformation, deformation of the appearance of metal materials, and fatal effects on the processing of mechanical parts. Therefore, this paper focuses on solving the causes of deformation in the thermal processing of metal materials, as well as solutions to improve the problems in the processing of metal materials.

Survival and Growth of Staphylococcus aureus on Temperature-Abused Beef Livers

1984 ◽  
Vol 47 (4) ◽  
pp. 260-262 ◽  
Author(s):  
B. W. BERRY ◽  
K. F. LEDDY ◽  
C. A. ROTHENBERG
Keyword(s):  
Staphylococcus Aureus ◽  
Storage Temperature ◽  
Frozen Storage ◽  
Storage Period ◽  
Developed Countries ◽  
Slow Surface ◽  
Plate Counts ◽  
Survival And Growth ◽  
High Storage ◽  
Storage Temperatures

Beef livers from freshly slaughtered cattle were inoculated with coagulase-positive Staphylococcus aureus and then placed in frozen storage. After 14 d of frozen storage, one-half of the livers were subjected to 21°C for 24 h followed by a 15-d period of storage at −1°C. The other livers were kept in frozen storage (−29°C) during this 15-d period after which all livers were subjected to either 10 or 21°C temperatures. S. aureus counts did not change during the 15-d storage period at −1°C, whereas aerobic plate counts (APC) increased by over 3 log10 cycles. The low storage temperature plus the growth of competitor bacteria most likely prevented S. aureus from proliferating. When all livers were subjected to 24 to 144 h of storage at either 10 or 21°C, those that had been subjected to 15 d of slow surface thawing displayed a lower S. aureus count and higher APC than livers subjected to rapid thawing followed by holding at the high temperatures. This may mean that if livers become contaminated with substantial numbers of S. aureus before freezing, then rapid thawing coupled with high storage temperatures (more typical of meat merchandising in less developed countries) could allow for rapid S. aureus growth before competitor organisms increase in numbers.

scholarly journals School meals in French secondary state schools with regard to the national recommendations

2008 ◽  
Vol 102 (2) ◽  
pp. 293-301 ◽  
Author(s):  
Carine Dubuisson ◽  
Sandrine Lioret ◽  
Gloria Calamassi-Tran ◽  
Jean-Luc Volatier ◽  
Lionel Lafay
Keyword(s):  
Fruits And Vegetables ◽  
Food Group ◽  
School Meals ◽  
Safety Issues ◽  
Group Frequency ◽  
Menu Analysis ◽  
Nationally Representative ◽  
State Schools ◽  
Nutrition Standards ◽  
Secondary State

In 2001, a circular addressing both the composition of school meals and food safety issues was introduced in France to improve the nutrient composition of school meals and provided food-frequency guidelines to guarantee dietary balanced meals. The present study assesses the extent to which secondary state schools are familiar with and implement this circular. In 2005, a nationally representative sample of 1440 secondary state schools received a questionnaire on their catering service and the implementation of the circular's recommendations, and were requested to enclose all menus (lunches and dinners) served over 1 month. Menu analysis shows that progress is still required to achieve a meal composition in accordance with the food-group frequency guidelines appended to the circular. Some recommendations are followed by most of the schools, such as limiting high-fat products and providing plenty of raw fruits and vegetables, cooked vegetables and starchy foods. Other guidelines should be implemented further, especially with regard to the nutritional quality of main courses and dairy products, which are met by less than a third and a half of schools, respectively. Specific efforts are necessary for evening meals to ensure that the nutritional requirements of boarders are covered. Some recommendations, such as the food purchasing manager being trained in nutrition (38 % of schools) and the involvement of dietetic expertise when designing meals (6 %), seem to be linked to better dietary balance of meals. Implementation of the circular must therefore be promoted in schools and may require stronger regulatory nutrition standards and better cooperation between schools.

Modification of Banding in Dual-Phase Steels via Thermal Processing

2014 ◽  
Vol 783-786 ◽  
pp. 1067-1072 ◽  
Author(s):  
K. Mukherjee ◽  
L.S. Thomas ◽  
C. Bos ◽  
David K. Matlock ◽  
John G. Speer
Keyword(s):  
Heating Rate ◽  
Thermal Processing ◽  
Thermomechanical Processing ◽  
Rolled Sheet ◽  
Dual Phase ◽  
Heating And Cooling ◽  
Heat Treated ◽  
Cold Rolled ◽  
Dp780 Steel ◽  
Microscopic Techniques

The potential to utilize controlled thermal processing to minimize banding in a DP780 steel with 2 wt pct Mn was evaluated on samples processed on a Gleeble® 3500 thermomechanical processing simulator. All processing histories were selected to result in final dual-phase steel microstructures simulating microstructures achievable during annealing of initially cold rolled sheet. Strip samples were processed to evaluate the effects of heating rate, annealing time, annealing temperature, and cooling rate. The degree of banding in the final microstructures was evaluated with standard light optical microscopic techniques. Results are presented to illustrate that the extent of banding depended on control of both heating and cooling rates, and a specific processing history based on a two-stage heating rate can be used to minimize visible banding in selected final heat treated products.

Effects of pre-treatment with extracts of Ocimum gratissimum and Vermonia amygdalina on proximate and organoleptic properties of processed Clarias gariepinus (Burchell, 1822)

2020 ◽  
Vol 35 (1) ◽  
pp. 39-46
Author(s):  
S.A. Ojukannaiye ◽  
L.A. Agbabiaka ◽  
I.I. Adedokun
Keyword(s):  
Clarias Gariepinus ◽  
Storage Period ◽  
Live Weight ◽  
Herbal Extract ◽  
Vernonia Amygdalina ◽  
Organoleptic Properties ◽  
Leaf Extracts ◽  
Mean Values ◽  
Ocimum Gratissimum ◽  
Fish Samples

The study evaluated nutritional and organoleptic properties of Clarias gariepinus pre-treated with aqueous leave extracts of Ocimum gratissimum and Vernonia amygdalina before processing. Thirty-six (36) C. gariepinus (live weight = 1.2± 0.2kg) samples were procured and processed for the study. Fish samples were divided into three parts of twelve fish each. Each part was grouped into three treatments having four fish in each group using a completely randomized design. Treatment one (T1) had fish immersed in 5% brine without herbal extract (control). In Treatment two (T2), fish were soaked in mixture of 5% brine and 5% O. gratissium (scent leaf) extracts while Treatment three (T3) had fish soaked in mixture of 5% brine and 5% V. amygdalina (bitter leaf) extracts all for 30 minutes. Treated fish samples were smoke-dried using charcoal kiln for 5 hours at temperature of 80 – 90° C. Samples were then cooled under ambient condition (30+3oC) for 4 hours. The smoke-dried fish samples were labeled according to treatments and stored for 7 days under aseptic condition. Organoleptic properties of the samples were conducted at every 24-hour of storage using a 9-point hedonic scale. Mean values of proximate composition of samples were significantly different (p<0.05). Protein content (70.01%) in T3 was higher than 68.31% and 66.62% in T2 and T1 respectively. Similarly, fat (5.12%) and ash (4.68%) levels for T3 were higher than 4.85% and 4.46% fat with 4.36% and 3.98% ash contents for T2 and T1 respectively. Results of mean scores for each organoleptic property decreased significantly (p<0.05) during storage period with no consistent trend in score pattern. Keywords: Clarias gariepinus, extract pretreatment, Ocimum gratissimum, organoleptic, Vernonia amygdalina.

Study of Alpha-Beta Transformation in Ti-6Al-4V-ELI. Mechanical and Microstructural Characteristics

2010 ◽  
Vol 638-642 ◽  
pp. 712-717 ◽  
Author(s):  
Pascual Tarín ◽  
Aurelio Gualo ◽  
Atonio Garcia Simón ◽  
Nuria M. Piris ◽  
Jose Maria Badía
Keyword(s):  
Beta Phase ◽  
Alpha Phase ◽  
Thermal Treatments ◽  
Conductivity Measurements ◽  
Transformation Kinetics ◽  
Microstructural Characteristics ◽  
Annealed Condition ◽  
Heat Treated ◽  
Metallographic Observation ◽  
Alpha Beta

In the Ti-6Al-4V-ELI alloy, the alpha phase is gradually transformed into the beta phase until beta-transus temperature ( 980°C) is reached, and the transformation is completed. It is important to identify the transformation kinetics to accomplish the solution heat treatments in which a phase alpha percentage remains unchanged. Kinetics and other transformation characteristics are evaluated, as well as their influence on subsequent cooling transformations, by differential and dilatometric thermal analysis, electric conductivity measurements, hardness measurements and metallographic observation, after performing controlled thermal treatments. Starting from the mill annealed condition, samples were heated at temperatures between 650-1000 °C for 1 hour, then water quenched and subsequently heated for aging, air cooled. Finally, the mechanical properties of samples heat treated were obtained.

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