scholarly journals Effect of storage temperature on crystal formation rate and growth rate of calcium lactate crystals on smoked Cheddar cheeses

2013 ◽  
Vol 96 (6) ◽  
pp. 3442-3448 ◽  
Author(s):  
P. Rajbhandari ◽  
J. Patel ◽  
E. Valentine ◽  
P.S. Kindstedt
Keyword(s):  
Growth Rate ◽  
Storage Temperature ◽  
Formation Rate ◽  
Calcium Lactate ◽  
Crystal Formation

scholarly journals Growth of Listeria monocytogenes in Thawed Frozen Foods

2017 ◽  
Vol 80 (3) ◽  
pp. 447-453 ◽  
Author(s):  
Ai Kataoka ◽  
Hua Wang ◽  
Philip H. Elliott ◽  
Richard C. Whiting ◽  
Melinda M. Hayman
Keyword(s):  
Growth Rate ◽  
Listeria Monocytogenes ◽  
Growth Rates ◽  
Storage Temperature ◽  
Growth Parameters ◽  
Quadratic Model ◽  
Lag Phase ◽  
Frozen Foods ◽  
Phase Duration ◽  
Primary Model

ABSTRACT The growth characteristics of Listeria monocytogenes inoculated onto frozen foods (corn, green peas, crabmeat, and shrimp) and thawed by being stored at 4, 8, 12, and 20°C were investigated. The growth parameters, lag-phase duration (LPD) and exponential growth rate (EGR), were determined by using a two-phase linear growth model as a primary model and a square root model for EGR and a quadratic model for LPD as secondary models, based on the growth data. The EGR model predictions were compared with growth rates obtained from the USDA Pathogen Modeling Program, calculated with similar pH, salt percentage, and NaNO2 parameters, at all storage temperatures. The results showed that L. monocytogenes grew well in all food types, with the growth rate increasing with storage temperature. Predicted EGRs for all food types demonstrated the significance of storage temperature and similar growth rates among four food types. The predicted EGRs showed slightly slower rate compared with the values from the U.S. Department of Agriculture Pathogen Modeling Program. LPD could not be accurately predicted, possibly because there were not enough sampling points. These data established by using real food samples demonstrated that L. monocytogenes can initiate growth without a prolonged lag phase even at refrigeration temperature (4°C), and the predictive models derived from this study can be useful for developing proper handling guidelines for thawed frozen foods during production and storage.

Modeling the Growth of Salmonella in Raw Poultry Stored under Aerobic Conditions

2008 ◽  
Vol 71 (12) ◽  
pp. 2429-2435 ◽  
Author(s):  
SILVIA A. DOMINGUEZ ◽  
DONALD W. SCHAFFNER
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Storage Temperature ◽  
Inoculum Size ◽  
Antibiotic Resistant ◽  
Aerobic Conditions ◽  
Root Model ◽  
Fail Safe ◽  
Spoilage Microflora ◽  
Raw Poultry

The presence of Salmonella in raw poultry is a well-recognized risk factor for foodborne illness. The objective of this study was to develop and validate a mathematical model that predicts the growth of Salmonella in raw poultry stored under aerobic conditions at a variety of temperatures. One hundred twelve Salmonella growth rates were extracted from 12 previously published studies. These growth rates were used to develop a square-root model relating the growth rate of Salmonella to storage temperature. Model predictions were compared to growth rate measurements collected in our laboratory for four poultry-specific Salmonella strains (two antibiotic-resistant and two nonresistant strains) inoculated onto raw chicken tender-loins. Chicken was inoculated at two levels (103 CFU/cm2 and ≤ 10 CFU/cm2) and incubated at temperatures ranging from 10 to 37°C. Visual inspection of the data, bias and accuracy factors, and comparison with two other published models were used to analyze the performance of the new model. Neither antibiotic resistance nor inoculum size affected Salmonella growth rates. The presence of spoilage microflora did not appear to slow the growth of Salmonella. Our model provided intermediate predicted growth rates when compared with the two other published models. Our model predicted slightly faster growth rates than those observed in inoculated chicken in the temperature range of 10 to 28°C but slightly slower growth rates than those observed between 30 and 37°C. Slightly negative bias factors were obtained in every case (−5to −3%); however, application of the model may be considered fail-safe for storage temperatures below 28°C.

scholarly journals Characterization of Urban New Particle Formation in Amman—Jordan

Atmosphere ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 79 ◽  
Author(s):  
Tareq Hussein ◽  
Nahid Atashi ◽  
Larisa Sogacheva ◽  
Simo Hakala ◽  
Lubna Dada ◽  
...  
Keyword(s):  
Growth Rate ◽  
Eastern Mediterranean ◽  
Seasonal Pattern ◽  
Formation Rate ◽  
Particle Formation ◽  
New Particle Formation ◽  
Vapor Source ◽  
Back Trajectories ◽  
Pattern Maximum ◽  
The Mean

We characterized new particle formation (NPF) events in the urban background of Amman during August 2016–July 2017. The monthly mean of submicron particle number concentration was 1.2 × 104–3.7 × 104 cm−3 (exhibited seasonal, weekly, and diurnal variation). Nucleation mode (10–15 nm) concentration was 0.7 × 103–1.1 × 103 cm−3 during daytime with a sharp peak (1.1 × 103–1.8 × 103 cm−3) around noon. We identified 110 NPF events (≈34% of all days) of which 55 showed a decreasing mode diameter after growth. The NPF event occurrence was higher in summer than in winter, and events were accompanied with air mass back trajectories crossing over the Eastern Mediterranean. The mean nucleation rate (J10) was 1.9 ± 1.1 cm−3 s−1 (monthly mean 1.6–2.7 cm−3 s−1) and the mean growth rate was 6.8 ± 3.1 nm/h (4.1–8.8 nm/h). The formation rate did not have a seasonal pattern, but the growth rate had a seasonal variation (maximum around August and minimum in winter). The mean condensable vapor source rate was 4.1 ± 2.2 × 105 molecules/cm3 s (2.6–6.9 × 105 molecules/cm3 s) with a seasonal pattern (maximum around August). The mean condensation sink was 8.9 ± 3.3 × 10−3 s−1 (6.4–14.8 × 10−3 s−1) with a seasonal pattern (minimum around June and maximum in winter).

scholarly journals Atmospheric particle formation events at Värriö measurement station in Finnish Lapland 1998–2002

2004 ◽  
Vol 4 (3) ◽  
pp. 3535-3563
Author(s):  
H. Vehkamäki ◽  
M. Dal Maso ◽  
T. Hussein ◽  
R. Flanagan ◽  
A. Hyvärinen ◽  
...  
Keyword(s):  
Growth Rate ◽  
Biological Activity ◽  
Gas Phase ◽  
Formation Rate ◽  
Particle Formation ◽  
Meteorological Conditions ◽  
Air Masses ◽  
Atmospheric Particle ◽  
Starting Time ◽  
Finnish Lapland

Abstract. We have identified 147 clear 8 nm diameter particle formation events at the SMEAR I station in Värriö, northern Finland during calendar years 1998–2002. The events have been classified in detail according to the particle formation rate, growth rate, event starting time, different gas phase species concentrations and pre-existing particle concentrations as well as various meteorological conditions. Most of the events occurred during the spring months between March and May, suggesting that increasing biological activity might produce the precursor gases for particle formation. The apparent 8 nm particle formation rates were around 0.1/cm3s, and they were uncorrelated with growth rates that vary between 0.5 and 10 nm/h. The air masses, which had clearly elevated sulphur dioxide concentrations above 1.6 ppb came, as expected, from the direction of Nikel and Monschegorsk smelteries. Only 15 formation events can be explained by the pollution plume from these sources.

scholarly journals Atmospheric new particle formation characteristics in the Arctic as measured at Mount Zeppelin, Svalbard, from 2016 to 2018

2020 ◽  
Vol 20 (21) ◽  
pp. 13425-13441
Author(s):  
Haebum Lee ◽  
Kwangyul Lee ◽  
Chris Rene Lunder ◽  
Radovan Krejci ◽  
Wenche Aas ◽  
...  
Keyword(s):  
Growth Rate ◽  
Dimethyl Sulfide ◽  
Formation Rate ◽  
Production Capacity ◽  
Particle Formation ◽  
The Arctic ◽  
New Particle Formation ◽  
Low Loss ◽  
H2so4 Concentration ◽  
Average Formation

Abstract. We conducted continuous measurements of nanoparticles down to 3 nm size in the Arctic at Mount Zeppelin, Ny Ålesund, Svalbard, from October 2016 to December 2018, providing a size distribution of nanoparticles (3–60 nm). A significant number of nanoparticles as small as 3 nm were often observed during new particle formation (NPF), particularly in summer, suggesting that these were likely produced near the site rather than being transported from other regions after growth. The average NPF frequency per year was 23 %, having the highest percentage in August (63 %). The average formation rate (J) and growth rate (GR) for 3–7 nm particles were 0.04 cm−3 s−1 and 2.07 nm h−1, respectively. Although NPF frequency in the Arctic was comparable to that in continental areas, the J and GR were much lower. The number of nanoparticles increased more frequently when air mass originated over the south and southwest ocean regions; this pattern overlapped with regions having strong chlorophyll a concentration and dimethyl sulfide (DMS) production capacity (southwest ocean) and was also associated with increased NH3 and H2SO4 concentration, suggesting that marine biogenic sources were responsible for gaseous precursors to NPF. Our results show that previously developed NPF occurrence criteria (low loss rate and high cluster growth rate favor NPF) are also applicable to NPF in the Arctic.

scholarly journals Intensifying the process of methane gas hydrates crystallization in the presence of surface-activated substances

2021 ◽  
Vol 230 ◽  
pp. 01004
Author(s):  
Olena Svietkina ◽  
Iryna Kovalevska ◽  
Kateryna Sai ◽  
Kostiantyn Prokopenko
Keyword(s):  
Experimental Data ◽  
Gas Hydrates ◽  
Surfactant Concentration ◽  
Crystallization Process ◽  
Molecular Diffusion ◽  
Formation Rate ◽  
Crystallization Rate ◽  
Crystal Formation ◽  
Methane Gas ◽  
Methane Gas Hydrates

The crystallization process of gas hydrates during their formation in the presence of surface-active substances (SAS) is studied. The research is conducted in two directions – theoretical and experimental. Experimental data on the crystallization rate of methane gas hydrates formation in the presence of surfactants have been obtained: high-molecular compounds are used on the basis of polymeric quaternary ammonium salts containing side aliphatic radicals of various lengths in the acyl fragment, as well as a number of specific surfactants. The process of methane gas hydrates formation is performed using a laboratory setup of the NPO modification for the gas hydrates creation. To analyse the experimental data, technical and metrological instruments are used: stalagmometric method with automatic photoelectric drop counting, conductometric method, Wheatstone bridge, spectrophotometric titration of amino end-groups, viscometer VPZh-1. It has been substantiated that the crystal formation rate depends on the surfactant concentration. New experimental dependences of the gas hydrates formation on surfactants under thermobaric conditions in the presence of surfactants have been found. It has been revealed that the crystallization process during the methane gas hydrates formation is accelerated in the presence of a surfactant. As a result of their application, the effect of solubilization and catalysis arises with the formation of the so-called “diffusion zone”, the size of which decreases in the presence of surfactants, thereby accelerating the substance transfer to the surface on which crystallization occurs. An increase in the surfactant concentration leads to an increase in the rate of molecular diffusion, and also creates a more intense turbulent diffusion.

scholarly journals Global analysis of continental boundary layer new particle formation based on long-term measurements

2018 ◽  
Author(s):  
Tuomo Nieminen ◽  
Veli-Matti Kerminen ◽  
Tuukka Petäjä ◽  
Pasi P. Aalto ◽  
Mikhail Arshinov ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Urban Areas ◽  
Global Analysis ◽  
Formation Rate ◽  
Particle Formation ◽  
Urban Environments ◽  
New Particle Formation ◽  
The World ◽  
Order Of Magnitude

Abstract. Atmospheric new particle formation (NPF) is an important phenomenon in terms of the global particle number concentrations. Here we investigated the frequency of NPF, formation rates of 10 nm particles and growth rates in the size range of 10–25 nm using at least one year of aerosol number size-distribution observations at 36 different locations around the world. The majority of these measurement sites are in the Northern Hemisphere. We found that the NPF frequency has a strong seasonal variability, taking place on about 30 % of the days in March–May and on about 10 % of the days in December–February. The median formation rate of 10 nm particles varies by about three orders of magnitude (0.01–10 cm−3 s−1) and the growth rate by about an order of magnitude (1–10 nm h−1). The smallest values of both formation and growth rates were observed at polar sites and the largest ones in urban environments or anthropogenically influenced rural sites. The correlation between the NPF event frequency and the particle formation and growth rate was at best moderate between the different measurement sites, as well as between the sites belonging to a certain environmental regime. For a better understanding of atmospheric NPF and its regional importance, we would need more observational data from different urban areas in practically all parts of the world, from additional remote and rural locations in Northern America, Asia and most of the Southern Hemisphere (especially Australia), from polar areas, and from at least a few locations over the oceans.

A Response Surface Model To Describe the Effect of Temperature and pH on the Growth of Bacillus cereus in Cooked Rice

2009 ◽  
Vol 72 (6) ◽  
pp. 1296-1300 ◽  
Author(s):  
SUN-KYUNG HEO ◽  
JI-YOUNG LEE ◽  
SEUNG-BUM BAEK ◽  
SANG-DO HA
Keyword(s):  
Growth Rate ◽  
Bacillus Cereus ◽  
Predictive Model ◽  
Response Surface ◽  
Storage Temperature ◽  
Growth Curves ◽  
Effect Of Temperature ◽  
Surface Model ◽  
Validation Data ◽  
Cooked Rice

This study was performed to develop a predictive model for the growth rate of Bacillus cereus in cooked rice. A response surface methodology (RSM) was used with a combination of storage temperature (10 to 40°C) and pH value (5.4 to 6.8). The growth curves generated under different conditions were fitted using a modified Gompertz equation, and the relationship of the growth rate to the growth curves was modeled using an RSM quadratic polynomial equation. The predictive model was significant (P < 0.01), and the predicted values of the growth parameters obtained using the model equations were in close agreement with experimental values (R2 = 0.9864). The RSM evaluation for describing the growth rate of B. cereus involved both a bias factor (Bf) and an accuracy factor (Af). Both the Bf value (1.006) and the Af value (1.011) approached 1.0 and were within acceptable ranges. Therefore, the adequacy of the predictive model for B. cereus in cooked rice was verified by the validation data.

scholarly journals An Emerging Translational Model to Screen Potential Medicinal Plants for Nephrolithiasis, an Independent Risk Factor for Chronic Kidney Disease

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
San-Yuan Wu ◽  
Jui-Lung Shen ◽  
Kee-Ming Man ◽  
Yuan-Ju Lee ◽  
Huey-Yi Chen ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Risk Factor ◽  
Kidney Disease ◽  
Medicinal Plants ◽  
Independent Risk Factor ◽  
Formation Rate ◽  
Screening Methods ◽  
Crystal Formation ◽  
Herbal Drugs ◽  
Translational Model

Pharmacological therapy for urolithiasis using medicinal plants has been increasingly adopted for the prevention of its recurrence. ADrosophila melanogastermodel developed for translational research of urolithiasis was applied to evaluate agents with potential antilithic effects and calcium oxalate (CaOx) formation. Potential antilithic herbs were prepared in a mixture of food in a diluted concentration of 5,000 from the original extract with 0.5% ethylene glycol (EG) as the lithogenic agent. The control group was fed with food only. After 3 weeks, flies (n≥150for each group) were killed using CO2narcotization, and the Malpighian tubules were dissected, removed, and processed for polarized light microscopy examination of the crystals. The crystal formation rate in the EG group was 100.0%. In the study, 16 tested herbal drugs reached the crystal formation rate of 0.0%, includingSalviae miltiorrhizae,Paeonia lactiflora, andCarthami flos.Scutellaria baicalensisenhanced CaOx crystal formation. Two herbal drugsCommiphora molmolandNatrii sulfascaused the death of all flies. Our rapid screening methods provided evidence that some medicinal plants have potential antilithic effects. These useful medicinal plants can be further studied using other animal or human models to verify their effects.Corrigendum to “An Emerging Translational Model to Screen Potential Medicinal Plants for Nephrolithiasis, an Independent Risk Factor for Chronic Kidney Disease”

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