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Rana YS, Chen L, Jiao Y, Johnson LM, Snyder AB. A meta-analysis of microbial thermal inactivation in low moisture foods. Food Microbiol 2024; 121:104515. [PMID: 38637077 DOI: 10.1016/j.fm.2024.104515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 02/27/2024] [Accepted: 03/04/2024] [Indexed: 04/20/2024]
Abstract
Microbial thermal inactivation in low moisture foods is challenging due to enhanced thermal resistance of microbes and low thermal conductivity of food matrices. In this study, we leveraged the body of previous work on this topic to model key experimental features that determine microbial thermal inactivation in low moisture foods. We identified 27 studies which contained 782 mean D-values and developed linear mixed-effect models to assess the effect of microorganism type, matrix structure and composition, water activity, temperature, and inoculation and recovery methods on cell death kinetics. Intraclass correlation statistics (I2) and conditional R2 values of the linear mixed effects models were: E. coli (R2-0.91, I2-83%), fungi (R2-0.88, I2-85%), L. monocytogenes (R2-0.84, I2-75%), Salmonella (R2-0.69, I2-46%). Finally, global response surface models (RSM) were developed to further study the non-linear effect of aw and temperature on inactivation. The fit of these models varied by organisms from R2 0.88 (E. coli) to 0.35 (fungi). Further dividing the Salmonella data into individual RSM models based on matrix structure improved model fit to R2 0.90 (paste-like products) and 0.48 (powder-like products). This indicates a negative relationship between data diversity and model performance.
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Affiliation(s)
| | - Long Chen
- Department of Food Science, Cornell University, Ithaca, NY, 14853, USA; College of Mechanical and Electronic Engineering, Northwest A & F University, Yangling, Shaanxi, 712100, China
| | - Yang Jiao
- Department of Food Science, Cornell University, Ithaca, NY, 14853, USA; College of Food Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
| | - Lynn M Johnson
- Cornell Statistical Consulting Unit, Cornell University, Ithaca, NY, 14853, USA
| | - Abigail B Snyder
- Department of Food Science, Cornell University, Ithaca, NY, 14853, USA.
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2
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Nutritional, Physicochemical, Functional, and Textural Properties of Red Pepper (Capsicum annuum L.), Red Onion (Allium cepa), Ginger (Zingiber officinale), and Garlic (Allium sativum): Main Ingredients for the Preparation of Spicy Foods in Ethiopia. J FOOD QUALITY 2023. [DOI: 10.1155/2023/3916692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023] Open
Abstract
Spices are known to have important benefits in our daily diet, and it is common to see industrial and traditional spicy foods in our households and markets. In the present work, a systematic profiling of the nutritional, physicochemical, and textural properties of red pepper, garlic, red onion, and ginger was conducted. The detailed data of forty eight (48) parameters that consisted of macronutrients, micronutrients, physicochemical properties, functional property, and rheological properties of each of the components were organized. The result showed that red pepper had the highest content of crude protein (14.7%), crude fat (11.3%), crude fiber (38.57%), ash (6.7%), redness (a
value) (32.5), CI (37.4%), and porosity (37.43%) compared to garlic, ginger, and red onion. Garlic had the highest content of carbohydrate content (76.42%), energy (346.58 kcal), pH (6.03), total soluble solid (26.76), particle size (D90, 561 µm), and volume weighted mean (238 µm) which is related to the high antimicrobial and antioxidant quality of garlic. Red onion had the highest content of Zn (71.16 mg/100 g), Na (94.5 mg/100 g), and Ca (71.16 mg/100 g) indicating that it is a rich source of minerals. The availability of data about the nutritional, physicochemical, functional, and textural properties of the ingredients is crucial for the production and formulation of industrial and traditional spicy foods with the highest quality and stability.
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3
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Wang L, Kang J, Zhu C, Zhou Z, Wang S, Huang Z. Modeling the RF heating uniformity contributed by a rotating turntable. J FOOD ENG 2023. [DOI: 10.1016/j.jfoodeng.2022.111289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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4
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Xue R, Wang H, Zhao D, Qin W, Lin H, Ye Q, Liu S. Identification of heat-resistant Bacillus strains in peppers in Sichuan Province, China. Lebensm Wiss Technol 2023. [DOI: 10.1016/j.lwt.2023.114425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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5
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Woldemariam HW, Emire SA, Teshome PG, Töpfl S, Aganovic K. Microbial inactivation and quality impact assessment of red pepper paste treated by high pressure processing. Heliyon 2022; 8:e12441. [PMID: 36590575 PMCID: PMC9798180 DOI: 10.1016/j.heliyon.2022.e12441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 08/11/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022] Open
Abstract
The study aimed to investigate inactivation of naturally occurring microorganisms and quality of red pepper paste treated by high pressure processing (HPP). Central composite rotatable design was employed to determine the impacts of pressure (100-600 MPa) and holding time (30-600 s). HPP at 527 MPa for 517 s reduced aerobic mesophilic bacteria count by 4.5 log CFU/g. Yeasts and molds counts were reduced to 1 log CFU/g at 600 MPa for 315 s. Total phenols, carotenoids and antioxidants activity ranged from 0.28 to 0.33 g GAE/100 g, 96.0-98.4 mg βc/100 g and 8.70-8.95 μmol TE/g, respectively. Increase (2.5-6.7%) in these variables was observed with increasing pressure and holding time. Total color difference (ΔE∗) values (0.2-2.8) were within the ranges of 'imperceptible' to 'noticeable'. Experimental results were fitted satisfactorily into quadratic model with higher R2 values (0.8619-0.9863). Optimization process suggested treatment of red pepper paste at 536 MPa for 125 s for maximum desirability (0.622). Validation experiments confirmed comparable percentage of relative errors. Overall, this technique could be considered as an efficient treatment for the inactivation of microorganisms that naturally occur in red pepper paste with minimal changes in its characteristics.
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Affiliation(s)
- Henock Woldemichael Woldemariam
- Food Engineering Graduate Program, School of Chemical and Bioengineering, Addis Ababa Institute of Technology, Addis Ababa University, Addis Ababa, Ethiopia
- Department of Food Engineering, College of Biological and Chemical Engineering, Addis Ababa Science and Technology University, Addis Ababa, Ethiopia
- Corresponding author.
| | - Shimelis Admassu Emire
- Food Engineering Graduate Program, School of Chemical and Bioengineering, Addis Ababa Institute of Technology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Paulos Getachew Teshome
- Center for Food Science and Nutrition, College of Natural and Computational Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Stefan Töpfl
- Osnabrueck University of Applied Sciences, Osnabrueck, Germany
| | - Kemal Aganovic
- German Institute of Food Technologies (DIL e.V.), Quakenbrueck, Germany
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6
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Sharma P, Xiao HW, Zhang Q, Sutar P. Intermittent high-power short-time microwave-vacuum treatment combined with steam impingement for effective microbial decontamination of black pepper (Piper nigrum). J FOOD ENG 2022. [DOI: 10.1016/j.jfoodeng.2022.111373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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7
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Pilot-Scale Radio Frequency-Assisted Pasteurization of Chili Powders Prepacked by Different Packaging Films. SUSTAINABILITY 2022. [DOI: 10.3390/su14159132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Radio frequency (RF) can penetrate most packaging films and has the advantages of pasteurizing prepackaged low-moisture foods and avoiding secondary contamination. The suitable films for prepacking chili powders and the corresponding pasteurization process are unclear. This study aimed to select a suitable film for prepackaging chili powders, optimize the parameters of RF heating prepackaged chili powders, and evaluate the effects of RF-assisted pasteurization on the quality of chili powders. The results showed that the non-woven fabric (NWF) is suitable for prepackaging chili powders by evaluating the influence of RF heating on packaging films (appearance, sealing performance, mechanical properties.). Using NWF, chili powders inoculated with Salmonella enterica Enteritidis PT 30 still achieved 6.81 ± 0.64 log CFU/g reduction, treated by RF heating at an average temperature of 67.06 °C for 7.5 min with an electrode gap of 110 mm, held for 12.5 min at a hot-air convection oven. The pasteurization process had no significant (p > 0.05) effect on the quality (appearance, volatile, and capsaicin) of chili powders. The results indicated that chili powders packed with NWF could still be effectively pasteurized by RF-assisted hot air. This study proposed a viable approach to avoid secondary contamination by adding packaging before pasteurization.
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Gao Y, Guan X, Wan A, Cui Y, Kou X, Li R, Wang S. Thermal Inactivation Kinetics and Radio Frequency Control of Aspergillus in Almond Kernels. Foods 2022; 11:foods11111603. [PMID: 35681353 PMCID: PMC9180863 DOI: 10.3390/foods11111603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 05/24/2022] [Accepted: 05/27/2022] [Indexed: 02/04/2023] Open
Abstract
Mold infections in almonds are a safety issue during post-harvest, storage and consumption, leading to health problems for consumers and causing economic losses. The aim of this study was to isolate mold from infected almond kernels and identify it by whole genome sequence (WGS). Then, the more heat resistant mold was selected and the thermal inactivation kinetics of this mold influenced by temperature and water activity (aw) was developed. Hot air-assisted radio frequency (RF) heating was used to validate pasteurization efficacy based on the thermal inactivation kinetics of this target mold. The results showed that the two types of molds were Penicillium and Aspergillus identified by WGS. The selected Aspergillus had higher heat resistance than the Penicillium in the almond kernels. Inactivation data for the target Aspergillus fitted the Weibull model better than the first-order kinetic model. The population changes of the target Aspergillus under the given conditions could be predicted from Mafart’s modified Bigelow model. The RF treatment was effectively used for inactivating Aspergillus in almond kernels based on Mafart’s modified Bigelow model and the cumulative lethal time model.
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Affiliation(s)
- Yu Gao
- College of Mechanical and Electronic Engineering, Northwest A&F University, Xianyang 712100, China; (Y.G.); (X.G.); (X.K.)
| | - Xiangyu Guan
- College of Mechanical and Electronic Engineering, Northwest A&F University, Xianyang 712100, China; (Y.G.); (X.G.); (X.K.)
| | - Ailin Wan
- College of Food Science and Engineering, Northwest A&F University, Xianyang 712100, China; (A.W.); (Y.C.)
| | - Yuan Cui
- College of Food Science and Engineering, Northwest A&F University, Xianyang 712100, China; (A.W.); (Y.C.)
| | - Xiaoxi Kou
- College of Mechanical and Electronic Engineering, Northwest A&F University, Xianyang 712100, China; (Y.G.); (X.G.); (X.K.)
| | - Rui Li
- College of Mechanical and Electronic Engineering, Northwest A&F University, Xianyang 712100, China; (Y.G.); (X.G.); (X.K.)
- Correspondence: (R.L.); (S.W.); Tel./Fax: +86-29-8709-2391 (R.L. & S.W.)
| | - Shaojin Wang
- College of Mechanical and Electronic Engineering, Northwest A&F University, Xianyang 712100, China; (Y.G.); (X.G.); (X.K.)
- Department of Biological Systems Engineering, Washington State University, Pullman, WA 99164-6120, USA
- Correspondence: (R.L.); (S.W.); Tel./Fax: +86-29-8709-2391 (R.L. & S.W.)
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Wason S, Verma T, Wei X, Mauromoustakos A, Subbiah J. Thermal inactivation kinetics of Salmonella enterica and Enterococcus faecium NRRL B- 2354 as a function of temperature and water activity in fine ground black pepper. Food Res Int 2022; 157:111393. [DOI: 10.1016/j.foodres.2022.111393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 05/11/2022] [Accepted: 05/19/2022] [Indexed: 11/29/2022]
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10
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Survival of Escherichia coli O157:H7 during Moderate Temperature Dehydration of Plant-Based Foods. Foods 2021; 10:foods10092162. [PMID: 34574271 PMCID: PMC8469793 DOI: 10.3390/foods10092162] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 08/25/2021] [Accepted: 08/30/2021] [Indexed: 01/03/2023] Open
Abstract
The effect of moderate-temperature (≤60 °C) dehydration of plant-based foods on pathogen inactivation is unknown. Here, we model the reduction of E. coli O157:H7 as a function of product-matrix, aw, and temperature under isothermal conditions. Apple, kale, and tofu were each adjusted to aw 0.90, 0.95, or 0.99 and inoculated with an E. coli O157:H7 cocktail, followed by isothermal treatment at 49, 54.5, or 60.0 °C. The decimal reduction time, or D-value, is the time required at a given temperature to achieve a 1 log reduction in the target microorganism. Modified Bigelow-type models were developed to determine D-values which varied by product type and aw level, ranging from 3.0–6.7, 19.3–55.3, and 45.9–257.4 min. The relative impact of aw was product dependent and appeared to have a non-linear impact on D-values. The root mean squared errors of the isothermal-based models ranged from 0.75 to 1.54 log CFU/g. Second, we performed dynamic drying experiments. While the isothermal results suggested significant microbial inactivation might be achieved, the dehydrator studies showed that the combination of low product temperature and decreasing aw in the pilot-scale system provided minimal inactivation. Pilot-scale drying at 60 °C only achieved reductions of 3.1 ± 0.8 log in kale and 0.67 ± 0.66 log in apple after 8 h, and 0.69 ± 0.67 log in tofu after 24 h. This illustrates the potential limitations of dehydration at ≤60 °C as a microbial kill step.
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11
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Tuly SS, Mahiuddin M, Karim A. Mathematical modeling of nutritional, color, texture, and microbial activity changes in fruit and vegetables during drying: A critical review. Crit Rev Food Sci Nutr 2021; 63:1877-1900. [PMID: 34459302 DOI: 10.1080/10408398.2021.1969533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Retention of quality attributes during drying of fruit and vegetables is a prime concern since the product's acceptability depends on the overall quality; particularly on the nutritional, color, and physical attributes. However, these quality parameters deteriorate during drying. Food quality changes are strongly related to the drying conditions and researchers have attempted to develop mathematical models to understand these relationships. A better insight toward the degradation of quality attributes is crucial for making real predictions and minimizing the quality deterioration. The previous empirical quality models employed kinetic modeling approaches to describe the quality changes and therefore, lack the realistic understanding of fundamental transport mechanisms. In order to develop a physics based mathematical model for the prediction of quality changes during drying, an in-depth understanding of research progress made toward this direction is indispensable. Therefore, the main goal of this paper is to present a critical review of the mathematical models developed and applied to describe the degradation kinetics of nutritional, color, and texture attributes during drying of fruit and vegetables and microbial growth model during storage. This review also presents the advantages and drawbacks of the existing models along with their industrial relevance. Finally, future research propositions toward developing physics-based mathematical model are presented.
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Affiliation(s)
- Sumaiya Sadika Tuly
- Faculty of Science and Engineering, Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
| | - Md Mahiuddin
- Faculty of Science and Engineering, Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
| | - Azharul Karim
- Faculty of Science and Engineering, Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
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12
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Cheng T, Tang J, Yang R, Xie Y, Chen L, Wang S. Methods to obtain thermal inactivation data for pathogen control in low-moisture foods. Trends Food Sci Technol 2021. [DOI: 10.1016/j.tifs.2021.03.048] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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13
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Zhang Z, Zhang B, Yang R, Zhao W. Recent Developments in the Preservation of Raw Fresh Food by Pulsed Electric Field. FOOD REVIEWS INTERNATIONAL 2020. [DOI: 10.1080/87559129.2020.1860083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Zhenna Zhang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, PR China
- Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment & Technology, Jiangnan University, Wuxi, Jiangsu, PR China
| | - Bin Zhang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, PR China
- Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment & Technology, Jiangnan University, Wuxi, Jiangsu, PR China
| | - Ruijin Yang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, PR China
- Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment & Technology, Jiangnan University, Wuxi, Jiangsu, PR China
| | - Wei Zhao
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, PR China
- Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment & Technology, Jiangnan University, Wuxi, Jiangsu, PR China
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Lin B, Zhu Y, Zhang L, Xu R, Guan X, Kou X, Wang S. Effect of Physical Structures of Food Matrices on Heat Resistance of Enterococcus faecium NRRL-2356 in Wheat Kernels, Flour and Dough. Foods 2020; 9:foods9121890. [PMID: 33352900 PMCID: PMC7765854 DOI: 10.3390/foods9121890] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 12/10/2020] [Accepted: 12/16/2020] [Indexed: 02/07/2023] Open
Abstract
Nonpathogenic surrogate microorganisms, with a similar or slightly higher thermal resistance of the target pathogens, are usually recommended for validating practical pasteurization processes. The aim of this study was to explore a surrogate microorganism in wheat products by comparing the thermal resistance of three common bacteria in wheat kernels and flour. The most heat-resistant Enterococcus faecium NRRL-2356 rather than Salmonella cocktail and Escherichia coli ATCC 25922 was determined when heating at different temperature-time combinations at a fixed heating rate of 5 °C/min in a heating block system. The most heat-resistant pathogen was selected to investigate the influences of physical structures of food matrices. The results indicated that the heat resistance of E. faecium was influenced by physical structures of food matrices and reduced at wheat kernel structural conditions. The inactivation of E. faecium was better fitted in the Weibull distribution model for wheat dough structural conditions while in first-order kinetics for wheat kernel and flour structural conditions due to the changes of physical structures during heating. A better pasteurization effect could be achieved in wheat kernel structure in this study, which may provide technical support for thermal inactivation of pathogens in wheat-based food processing.
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Affiliation(s)
- Biying Lin
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, China; (B.L.); (L.Z.); (R.X.); (X.G.); (X.K.)
| | - Yufei Zhu
- College of Animal Science and Technology, Northwest A&F University, Yangling 712100, China;
| | - Lihui Zhang
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, China; (B.L.); (L.Z.); (R.X.); (X.G.); (X.K.)
| | - Ruzhen Xu
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, China; (B.L.); (L.Z.); (R.X.); (X.G.); (X.K.)
| | - Xiangyu Guan
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, China; (B.L.); (L.Z.); (R.X.); (X.G.); (X.K.)
| | - Xiaoxi Kou
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, China; (B.L.); (L.Z.); (R.X.); (X.G.); (X.K.)
| | - Shaojin Wang
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712100, China; (B.L.); (L.Z.); (R.X.); (X.G.); (X.K.)
- Department of Biological Systems Engineering, Washington State University, Pullman, WA 99164-6120, USA
- Correspondence: ; Tel.: +86-29-87092391; Fax: +86-29-87091737
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15
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Thermal inactivation kinetics of Salmonella and Enterococcus faecium NRRL B-2354 on dried basil leaves. Food Microbiol 2020; 96:103710. [PMID: 33494891 DOI: 10.1016/j.fm.2020.103710] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 11/27/2020] [Accepted: 11/30/2020] [Indexed: 01/14/2023]
Abstract
The enhanced heat resistance of Salmonella developed at low water activity makes it a serious challenge to eliminate them during thermal processing. The objectives of this research are to (i) investigate the effect of water activity on thermal inactivation of Salmonella cocktail (Agona, Tennessee, Mbandaka, Montevideo, and Reading) in dried basil leaves, and (ii) evaluate Enterococcus faecium NRRL B-2354 as an appropriate surrogate for Salmonella in dried basil leaves. Dried basil leaves, inoculated with a Salmonella cocktail and E. faecium separately, were equilibrated to different water activities (aw: 0.40, 0.55, and 0.70) in a humidity-controlled chamber. The basil samples were packed (1.6 ± 0.1 g) in aluminum pouches and thermally treated at 70, 75, and 80 °C using a dry heating method for 0-180 min to obtain the thermal death curve. The microbial survival data was fit using two primary models (Log-linear and Weibull model). Results from AICc showed that the log-linear model fits well for thermal inactivation of both microorganisms. As the aw decreases from 0.70 to 0.40 at 75 °C, the D-value increases from 3.30 to 9.14 min for Salmonella and 6.53 to 14.07 min for E. faecium. Based on the AICc values, the modified Bigelow model fits the D-values better than the response surface model for both the microorganisms. The kill ratio of surrogate to pathogen ranged from 1.4 to 2.8, indicating that it is a conservative surrogate for Salmonella for performing validation of the thermal pasteurization process. The identification of suitable surrogate and development of modified Bigelow model will help the spice industry in developing the thermal processes for improving the safety of basil leaves.
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16
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Gautam B, Govindan BN, Gӓnzle M, Roopesh MS. Influence of water activity on the heat resistance of Salmonella enterica in selected low-moisture foods. Int J Food Microbiol 2020; 334:108813. [PMID: 32841809 DOI: 10.1016/j.ijfoodmicro.2020.108813] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 04/23/2020] [Accepted: 08/01/2020] [Indexed: 10/23/2022]
Abstract
Low-moisture foods (LMF with water activity, aw < 0.85) including pet foods and black pepper powder have consistently been associated with foodborne disease caused by Salmonella enterica. Increased heat resistance and prolonged survival at low-moisture conditions, however, remain major challenges to achieve effective inactivation of Salmonella in low-moisture foods. At low water activity (aw) conditions, heat resistance of Salmonella is greatly enhanced when compared to high aw conditions. This study aimed to quantify the effect of aw on the heat resistance of Salmonella enterica in pet food pellets and black pepper powder. Pet food pellets were inoculated with two strains of heat resistant S. enterica and black pepper powder was inoculated with a 5-strain cocktail of Salmonella. Both inoculated food samples were equilibrated at 0.33, 0.54, and 0.75 aw in controlled humidity chambers. Inoculated pet food pellets and black pepper powder in closed aluminum cells were heat treated at specific temperatures for selected times. The results showed that the Weibull model fitted well the inactivation data. At a specific temperature, the rate of inactivation increased with the increase in the aw from 0.33 to 0.75, and the 3-log reduction times decreased for Salmonella in both food samples with the increase in aw. Water adsorption isotherms of pet food pellets and black pepper powder at initial and treatment temperatures were developed to understand the change in aw during heat treatments. The change in aw during heat treatment was dependent on the type of food matrix, which possibly influenced the thermal inactivation of Salmonella in pet food pellets and black pepper powder. The quantitative analysis of heat reduction of Salmonella with respect to aw aids in selection of the appropriate initial aw to develop effective heat treatment protocols for adequate reduction of Salmonella in pet foods and black pepper powder.
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Affiliation(s)
- Bina Gautam
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Byju N Govindan
- Department of Entomology, University of Minnesota, 1980 Folwell Avenue, 219 Hodson Hall, St. Paul, MN 55108, USA
| | - Michael Gӓnzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - M S Roopesh
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada.
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17
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Zhang L, Lan R, Zhang B, Erdogdu F, Wang S. A comprehensive review on recent developments of radio frequency treatment for pasteurizing agricultural products. Crit Rev Food Sci Nutr 2020; 61:380-394. [PMID: 32156148 DOI: 10.1080/10408398.2020.1733929] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Recent pathogen incidents have forced food industry to seek for alternative processes in postharvest pasteurization of agricultural commodities. Radio frequency (RF) heating has been used as one alternative treatment to replace chemical fumigation and other conventional thermal methods since it is relatively easy to apply and leaves no chemical residues. RF technology transfers electromagnetic energy into large bulk volume of the products to provide a fast and volumetric heating. There are two types of RF technology commonly applied in lab and industry to generate the heat energy: free running oscillator and 50-Ω systems. Several reviews have been published to introduce the application of RF heating in food processing. However, few reviews have a comprehensive summary of RF treatment for pasteurizing agricultural products. The objective of this review was to introduce the developments in the RF pasteurization of agricultural commodities and to present future directions of the RF heating applications. While the recent developments in the RF pasteurization were presented, thermal death kinetics of targeted pathogens as influenced by water activity, pathogen species and heating rates, non-thermal effects of RF heating, combining RF heating with other technologies for pasteurization, RF heating uniformity improvements using computer simulation and development of practical RF pasteurization processes were also focused. This review is expected to provide a comprehensive understanding of RF pasteurization for agricultural products and promote the industrial-scale applications of RF technology with possible process protocol optimization purposes.
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Affiliation(s)
- Lihui Zhang
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, China
| | - Ruange Lan
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, China
| | - Beihua Zhang
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, China
| | - Ferruh Erdogdu
- Department of Food Engineering, Ankara University, Golbası-Ankara, Turkey
| | - Shaojin Wang
- College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, China.,Department of Biological Systems Engineering, Washington State University, Pullman, Washington, USA
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