Impact of Process Temperature, Humidity, and Initial Product Moisture on Thermal Inactivation of Salmonella Enteritidis PT 30 on Pistachios during Hot-Air Heating

2018 ◽  
Vol 81 (8) ◽  
pp. 1351-1356 ◽  
Author(s):  
KAITLYN E. CASULLI ◽  
FRANCISCO J. GARCES-VEGA ◽  
KIRK D. DOLAN ◽  
ELLIOT T. RYSER ◽  
LINDA J. HARRIS ◽  
...  
Keyword(s):  
Salmonella Enteritidis ◽  
Thermal Inactivation ◽  
Pure Water ◽  
Dew Point ◽  
Process Temperature ◽  
Thermal Processes ◽  
Initial Product ◽  
Log Reduction ◽  
Product And Process ◽  
The Impact

ABSTRACT Some thermal processes, such as pistachio roasting, are not yet well characterized with respect to the impact of product and process variables on Salmonella lethality. This study aimed to quantify the effects of process temperature, humidity, and initial product water activity (aw), on Salmonella lethality for in-shell pistachios. In-shell pistachios were inoculated with Salmonella Enteritidis PT 30 (∼8.5 log CFU/g), equilibrated (0.45 or 0.65 aw), and heated without soaking (“dry”) or after a pure-water or 27% NaCl brining pretreatment (“presoaked”). Inoculated pistachio samples (15 g) were heated in a laboratory-scale, moist-air convection oven at 104.4 or 118.3°C, humidities of ∼3, 15, or 30%, v/v (∼24.4, 54.4, or 69.4°C dew point), and air speed of 1.3 m/s. Salmonella survivors were quantified at six times during each treatment, targeting total reductions of ∼3 to 5 log. Survivor data were analyzed using analysis of variance to identify main effects (time, temperature, humidity, and initial aw) and two-term interactions with time. As expected, lethality increased (P < 0.05) with temperature and humidity. For example, the time to achieve a 4-log reduction decreased 50 to 80% when humidity increased from ∼3 to 30%. When the dry and presoaked treatments were analyzed separately, initial product aw (0.45 versus 0.65 aw or 0.75 versus 0.95 aw) did not affect lethality (P > 0.05). However, when comparing dry against presoaked treatments, the time to achieve a 4-log reduction decreased 55 to 85% (P < 0.05) for presoaked pistachios subjected to the same temperature-humidity treatment. Salt had no effect (P > 0.05) on lethality outcomes. These results, relative to initial aw, process humidity, brining, and salt effects on process lethality, are critically important and must be considered in the design and validation of thermal processes for Salmonella reduction in pistachio processing.

Extended Study on the Influence of z-Value(s) of Single and Multicomponent Time-Temperature Integrators on the Accuracy of Quantitative Thermal Process Assessment

2005 ◽  
Vol 68 (2) ◽  
pp. 384-395 ◽  
Author(s):  
YANN P. GUIAVARC'H ◽  
ANN M. VAN LOEY ◽  
MARC E. HENDRICKX
Keyword(s):  
Thermal Process ◽  
Thermal Processes ◽  
Temperature Profiles ◽  
Large Database ◽  
Wide Range ◽  
Two Component ◽  
Food Sterilization ◽  
Z Value ◽  
Product And Process ◽  
The Impact

The possibilities and limitations of single- and multicomponent time-temperature integrators (TTIs) for evaluating the impact of thermal processes on a target food attribute with a ztarget value different from the zTTI value(s) of the TTI is far from sufficiently documented. In this study, several thousand time-temperature profiles were generated by heat transfer simulations based on a wide range of product and process thermal parameters and considering a ztarget value of 10°C and a reference temperature of 121.1°C, both currently used to assess the safety of food sterilization processes. These simulations included 15 different F121.1°C values in the range 3 to 60 min. The integration of the time-temperature profiles with ztarget 10 C zTTI values of 5.5 to 20.5°C in steps of 1°C allowed generation of a large database containing for each combination of product and process parameters the correction factor to apply to the process value FmultiTTI, which was derived from a single- or multicomponent TTI, to obtain the target process value 10°CF121.1°C. The table and the graph results clearly demonstrated that multicomponent TTIs with z-values close to 10°C can be used as an extremely efficient approach when a single-component TTI with a z-value of 10°C is not available. In particular, a two-component TTI with z1 and z2 values respectively above and below the ztarget value (10°C in this study) would be the best option for the development of a TTI to assess the safety of sterilized foods. Whatever process and product parameters are used, such a TTI allows proper evaluation of the process value 10°CF121.1°C.

Thermal Inactivation Kinetics for Salmonella Enteritidis PT30 on Almonds Subjected to Moist-Air Convection Heating

2009 ◽  
Vol 72 (8) ◽  
pp. 1602-1609 ◽  
Author(s):  
SANGHYUP JEONG ◽  
BRADLEY P. MARKS ◽  
ALICIA ORTA-RAMIREZ
Keyword(s):  
Salmonella Enteritidis ◽  
Thermal Inactivation ◽  
Dew Point ◽  
Traditional Model ◽  
Moist Air ◽  
Validation Data ◽  
Dynamic Surface ◽  
Modified Model ◽  
Air Heating ◽  
Z Value

A traditional thermal inactivation kinetic model (D- and z-value) was modified to account for the effect of process humidity on thermal inactivation of Salmonella Enteritidis PT30 on the surface of almonds subjected to moist-air heating. Raw almonds were surface inoculated to ∼108 CFU/g and subjected to moist-air heating in a computer-controlled laboratory-scale convection oven. Time-temperature data were collected for 125 conditions (five dry bulb temperatures, 121 to 232°C; five process humidity levels, 5 to 90% moisture by volume; and five process durations). Moisture status at the surface of the almond, rather than the humidity of the bulk air, was a primary factor controlling the rate of inactivation; therefore, the D-value could not be a simple function of process temperature. Instead, the traditional D- and z-value model was modified to account for the dynamic water status at the surface of the product under humid heating conditions. The modified model needs only the dew point temperature of the processing air and dynamic surface temperature history of the almonds during moist-air heating. The modified model was more robust and accurate than the traditional model. The accuracy of the modified model was improved by 32 to 44% (in terms of the root mean squared error [RMSE] for the model fit) when compared with the traditional model in all moist-air heating conditions. Also, the prediction error of the modified model (RMSE = 1.33 log reductions) against an independent validation data set was approximately one-half that of the traditional model (RMSE = 2.56 log reduction) in the humidity range of 5 to 90% moisture by volume.

Propylparaben Sensitizes Heat-Resistant Salmonella Enteritidis and Salmonella Oranienburg to Thermal Inactivation in Liquid Egg Albumen†

2012 ◽  
Vol 75 (3) ◽  
pp. 443-448 ◽  
Author(s):  
JOSHUA B. GURTLER ◽  
TONY Z. JIN
Keyword(s):  
Salmonella Enteritidis ◽  
Thermal Inactivation ◽  
Egg White ◽  
Antibacterial Efficacy ◽  
Department Of Agriculture ◽  
Log Reduction ◽  
Egg Albumen ◽  
Inspection Service ◽  
Thermal Pasteurization ◽  
The U.S

Propyl p-hydroxybenzoic acid (propylparaben [PRPA]) is a phenolic antioxidant, known to occur in nature and used as a microbiostat in foods, feeds, pharmaceuticals, cosmetics, and medications. The U.S. Department of Agriculture, Food Safety and Inspection Service (FSIS) requires that liquid egg white (LEW) be pasteurized at 56.7°C for 3.5 min. This study evaluated the effects of PRPA on the pasteurization sensitivity of Salmonella in LEW. When LEW (pH 7.8) was pasteurized under FSIS conditions, salmonellae declined by 0.5, 4.6, 4.5, >7.0, and >7.0 log CFU/ml, with 0, 125, 250, 500, or 1,000 ppm of PRPA, respectively, and D56.7°C-values were 2.99, 1.05, 0.68, 0.26 and ≤0.16 min. Albumen (pH 8.9) pasteurized under FSIS standards incurred salmonellae reductions of 3.3, 2.8, 5.2, >7.0, and >7.0 log CFU/ml, with 0, 125, 250, 500, or 1,000 ppm of PRPA, respectively, while D56.7°C-values were 0.87, 0.99, 0.66, 0.22, and 0.09 min. Adding 500 ppm of PRPA to albumen (pH 7.8) reduced D56.7°C-values more than 11-fold, and reduced the time to achieve a 5-log reduction from 15.0 to only 1.3 min. A 7-log reduction in plain LEW (pH 7.8) at 56.7°C required 20.9 min, versus only 1.8 and 1.1 min with 500 and 1,000 ppm of PRPA, respectively. Furthermore, a 7-log reduction in plain LEW (pH 8.9) required 6.1 min, versus only 1.5 and 0.6 min with 500 and 1,000 ppm of PRPA, respectively. This study is the first to report the efficacy of PRPA (pKa = 8.4) in sensitizing Salmonella in LEW to thermal pasteurization, while documenting that PRPA retains its antibacterial efficacy at pH levels as high as 8.9.

Modeling the Effects of Product Temperature, Product Moisture, and Process Humidity on Thermal Inactivation of Salmonella in Pistachios during Hot-Air Heating

2020 ◽  
Vol 84 (1) ◽  
pp. 47-57
Author(s):  
KAITLYN E. CASULLI ◽  
KIRK D. DOLAN ◽  
BRADLEY P. MARKS
Keyword(s):  
Moisture Content ◽  
Salmonella Enteritidis ◽  
Thermal Inactivation ◽  
Mean Squared Error ◽  
Dew Point ◽  
Moist Air ◽  
Product Temperature ◽  
Air Heating ◽  
Air Convection ◽  
Primary Model

ABSTRACT Prior efforts to model bacterial thermal inactivation in and on low-moisture foods generally have been based on isothermal and iso-moisture experiments and have rarely included dynamic product and process variables. Therefore, the objective of this study was to test appropriate secondary models to quantify the effect of product temperature, product moisture, and process humidity on thermal inactivation of Salmonella Enteritidis PT30 on pistachios subjected to dynamic dry- or moist-air heating. In-shell pistachios were inoculated with Salmonella Enteritidis PT30, equilibrated in controlled-humidity chambers (to target water activities [aw] of 0.45 or 0.65), and in some cases, subjected to a presoak treatment prior to heating in a laboratory-scale, moist-air convection oven at multiple combinations (in duplicate) of dry bulb (104.4 or 118.3°C) and dew point (∼23.8, 54.4, or 69.4°C) temperatures, with air speed of ∼1.3 m/s. Salmonella survivors, pistachio moisture content, and aw were quantified at six time points for each condition, targeting cumulative lethality of ∼3 to 5 log. The resulting data were used to estimate parameters for five candidate secondary models that included combinations of product temperature, product moisture, aw, and/or process dew point (coupled with a log-linear primary model). A model describing the D-value as a function of temperature and dew point fit the data well (root mean squared error [RMSE] = 0.86 log CFU/g); however, adding a term to account for dynamic product moisture improved the fit (RMSE = 0.83 log CFU/g). In addition, product moisture content yielded better model outcomes, as compared with aw, particularly in the case of the presoaked pistachios. When validated at the pilot scale, the model was conservative, always underpredicting the experimental log reductions. Both dynamic product moisture and process humidity were critical factors in modeling thermal inactivation of Salmonella in a low-moisture product heated in an air-convection system. HIGHLIGHTS

Effect of the Local Microenvironment on Survival and Thermal Inactivation of Salmonella in Low- and Intermediate-Moisture Multi-Ingredient Foods

2014 ◽  
Vol 77 (1) ◽  
pp. 67-74 ◽  
Author(s):  
HAIPING LI ◽  
XIAOWEN FU ◽  
YIGE BIMA ◽  
JOHN KOONTZ ◽  
CHRISTINA MEGALIS ◽  
...  
Keyword(s):  
Process Design ◽  
Thermal Inactivation ◽  
Peanut Butter ◽  
Survival Rates ◽  
Milk Powder ◽  
Model Systems ◽  
Log Reduction ◽  
Two Systems ◽  
Special Challenge ◽  
The Impact

Multi-ingredient foods having low- or intermediate-moisture characteristics may pose a special challenge to process design and validation. Ingredients of these foods can create local microenvironments that may have a distinct impact on pathogen survival and processing requirements. In this study, two model systems, each consisting of 80% commercial peanut butter (P) and 20% nonfat dry milk powder (M), were formulated to be identical in composition, but different in the source of the Salmonella contamination as originating in either the ingredient P or M. Immediately after inoculation, Salmonella showed a 2.0-log reduction when M was the contaminated ingredient compared with a 0.6-log reduction when P was the contaminated ingredient. This pattern of survival was consistent with the single-ingredient control containing only M (2.5-log reduction) or only P (0.7-log reduction), suggesting that the immediate proximity of cells is determined by the contaminated ingredient in the model system. After 5 weeks of storage, the survival rates of Salmonella in the two systems remained different, i.e. a 4- and 2-log reduction resulted in the system with M or P as the contaminated ingredient, respectively. Furthermore, thermal inactivation efficacies also differed significantly between the two systems. Fourier transform infrared spectroscopy demonstrated the nonhomogeneous distribution of water, lipid, and protein, indicating that varied local microenvironments were present and likely affected the behavior of the pathogen. The impact of the microenvironment on inactivation and survival of Salmonella was further confirmed in a butter cookie formulation in which Salmonella was inoculated via four different ingredients. This study shows that the local microenvironment in low- and intermediate-moisture foods affects Salmonella survival and thermal inactivation. The ingredient source of the contamination should be taken into account for process design and validation to ensure the safety of the product.

Impact of Particulate Matter on Distribution System Disinfection Efficacy

2008 ◽  
Vol 43 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Linda Wojcicka ◽  
Carole Baxter ◽  
Ron Hofmann
Keyword(s):  
Helicobacter Pylori ◽  
Particulate Matter ◽  
Distribution System ◽  
Contact Time ◽  
Water Disinfection ◽  
Sphingomonas Paucimobilis ◽  
Soil Corrosion ◽  
Log Reduction ◽  
Drinking Water Disinfection ◽  
The Impact

Abstract Microorganisms have been shown to survive drinking water disinfection and remain viable in disinfected waters despite the presence of disinfectant residuals. This may be partially attributed to protection by particulate matter. The aim of this study was to determine the effects of the presence of particulate matter on disinfection kinetics. Sphingomonas paucimobilis ATCC 10829 and Helicobacter pylori ATCC 43504 were used in inactivation experiments in the presence and absence of soil, corrosion, and wastewater particles. The results showed that the presence of such particles tended to inhibit chlorine and monochloramine inactivation, although the magnitude of the impact under the conditions tested was small (e.g., 1-log reduction in inactivation for several minutes of contact time in the presence of less than 1 mg/L of disinfectant).

scholarly journals Process Modeling and Simulation of Tableting—An Agent-Based Simulation Methodology for Direct Compression

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 996
Author(s):  
Niels Lasse Martin ◽  
Ann Kathrin Schomberg ◽  
Jan Henrik Finke ◽  
Tim Gyung-min Abraham ◽  
Arno Kwade ◽  
...  
Keyword(s):  
Raw Materials ◽  
Pilot Scale ◽  
Physical Models ◽  
Agent Based Simulation ◽  
Validation Data ◽  
Agent Based ◽  
Industrial Processing ◽  
Digital Twins ◽  
Product And Process ◽  
The Impact

In pharmaceutical manufacturing, the utmost aim is reliably producing high quality products. Simulation approaches allow virtual experiments of processes in the planning phase and the implementation of digital twins in operation. The industrial processing of active pharmaceutical ingredients (APIs) into tablets requires the combination of discrete and continuous sub-processes with complex interdependencies regarding the material structures and characteristics. The API and excipients are mixed, granulated if required, and subsequently tableted. Thereby, the structure as well as the properties of the intermediate and final product are influenced by the raw materials, the parametrized processes and environmental conditions, which are subject to certain fluctuations. In this study, for the first time, an agent-based simulation model is presented, which enables the prediction, tracking, and tracing of resulting structures and properties of the intermediates of an industrial tableting process. Therefore, the methodology for the identification and development of product and process agents in an agent-based simulation is shown. Implemented physical models describe the impact of process parameters on material structures. The tablet production with a pilot scale rotary press is experimentally characterized to provide calibration and validation data. Finally, the simulation results, predicting the final structures, are compared to the experimental data.

scholarly journals A Reference Framework to Combine Model-Based Design and AR to Improve Social Sustainability

2021 ◽  
Vol 13 (4) ◽  
pp. 2031
Author(s):  
Fabio Grandi ◽  
Riccardo Karim Khamaisi ◽  
Margherita Peruzzini ◽  
Roberto Raffaeli ◽  
Marcello Pellicciari
Keyword(s):  
Positive Impact ◽  
Cost Effective ◽  
Digital Models ◽  
Model Based ◽  
Digital Contents ◽  
Recent Developments ◽  
Virtual Simulations ◽  
Product And Process ◽  
The Impact ◽  
Time Information

Product and process digitalization is pervading numerous areas in the industry to improve quality and reduce costs. In particular, digital models enable virtual simulations to predict product and process performances, as well as to generate digital contents to improve the general workflow. Digital models can also contain additional contents (e.g., model-based design (MBD)) to provide online and on-time information about process operations and management, as well as to support operator activities. The recent developments in augmented reality (AR) offer new specific interfaces to promote the great diffusion of digital contents into industrial processes, thanks to flexible and robust applications, as well as cost-effective devices. However, the impact of AR applications on sustainability is still poorly explored in research. In this direction, this paper proposed an innovative approach to exploit MBD and introduce AR interfaces in the industry to support human intensive processes. Indeed, in those processes, the human contribution is still crucial to guaranteeing the expected product quality (e.g., quality inspection). The paper also analyzed how this new concept can benefit sustainability and define a set of metrics to assess the positive impact on sustainability, focusing on social aspects.

On the benefit of the Canadian Small Lake Model to better represent the impact of small natural lakes on GEM-Hydro streamflow simulations.

2021 ◽  
Author(s):  
Etienne Gaborit ◽  
Murray MacKay ◽  
Camille Garnaud ◽  
Vincent Fortin
Keyword(s):  
Water Balance ◽  
Grid Point ◽  
Hydrologic Model ◽  
Surface Fluxes ◽  
Dew Point ◽  
Multiple Model ◽  
Small Lake ◽  
Surface Component ◽  
Lake Model ◽  
The Impact

<p>This study aims at assessing the impact of a new lake model on streamflow simulations performed with the GEM-Hydro hydrologic model developed at ECCC. GEM-Hydro is at the heart of the National Surface and River Prediction System (NSRPS) which ECCC uses to forecast river flows over most of Canada. The GEM-Hydro model mainly consists of the GEM-Surf component to represent surface processes, and of the Watroute model to represent river and lake routing, in order to perform streamflow simulations and forecasts. The surface component of GEM-Hydro can simulate 5 different types of surfaces.  Currently, the water tile consists of a very simple algorithm which, in terms of water balance, consists of producing runoff fluxes simply equal to precipitation minus evaporation. This runoff over water surfaces is then provided as input, along with runoff and drainage generated over other surface tiles, to the Watroute model. The Watroute version used in GEM-Hydro currently only represents major lakes (area greater than 100km<sup>2</sup>) along the river networks, and does not represent the impact that small lakes can have on streamflow, which mainly consists in slowing down runoff before it reaches the main streams of the network.</p><p>Recently, the Canadian Small Lake Model (CSLM) was implemented in the surface component of GEM-Hydro to represent the energy and water balance over water tiles more accurately. So far, CSLM simulations have been shown promising in terms of evaporation, ice cover, absolute and dew point temperature simulations, compared with the former algorithm used over water. However, the impact of CSLM on the resulting streamflow simulations performed with GEM-Hydro has not been evaluated yet. This study aims first at evaluating the impact of CSLM on streamflow simulations, and secondly at testing different CSLM configurations as well as different coupling strategies with Watroute, with the objective of finding the best set up for the prediction of streamflow in Canada. For example, overland runoff generated by the land tile can be provided to the water tile of the same grid point in different ways, and the outflow computed at the outlet of the water tile can be computed with different parameters. Moreover, different outflow computations have to be taken into account depending on if the water tile of a grid point represents subgrid-scale lakes, or if on the contrary it belongs to a lake spanning over multiple model grid points.</p><p>To do so, different GEM-Hydro open-loop simulations have been performed on the Lake of the Woods watershed, located in Canada, with and without CSLM to represent water tiles. The CSLM configurations leading to the best results are presented here. CSLM simulations are also evaluated in terms of surface fluxes, to ensure that the main purpose of the model, which is to improve surface fluxes to ultimately improve atmospheric forecasts, is preserved, compared to the default configuration of the model. Ideas for further improving the coupling between the GEM-Hydro surface and routing components, in terms of lake processes, are also presented and will be tested in future work.</p>

Sign in / Sign up

Export Citation Format

Share Document