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Hai D, Jiang H, Meng Z, Qiao M, Xu T, Song L, Huang X. The Impact of High Temperature on Microbial Communities in Pork and Duck Skin. Microorganisms 2023; 11:2869. [PMID: 38138014 PMCID: PMC10746068 DOI: 10.3390/microorganisms11122869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/12/2023] [Accepted: 11/16/2023] [Indexed: 12/24/2023] Open
Abstract
Pork skin and duck skin are highly favored by consumers in China, and high-temperature processing methods are widely employed in cooking and food preparation. However, the influence of high-temperature treatment on the microbial communities within pork skin and duck skin remains unclear. In this study, a high-temperature treatment method simulating the cooking process was utilized to treat samples of pork skin and duck skin at temperatures ranging from 60 °C to 120 °C. The findings revealed that high-temperature treatment significantly altered the microbial communities in both pork skin and duck skin. Heat exposure resulted in a decrease in microbial diversity and induced changes in the relative abundance of specific microbial groups. In pork skin, high-temperature treatment led to a reduction in bacterial diversity and a decline in the relative abundance of specific bacterial taxa. Similarly, the relative abundance of microbial communities in duck skin also decreased. Furthermore, potential pathogenic bacteria, including Gram-positive and Gram-negative bacteria, as well as aerobic, anaerobic, and facultative anaerobic bacteria, exhibited different responses to high-temperature treatment in pork skin and duck skin. These findings highlighted the substantial impact of high-temperature processing on the composition and structure of microbial communities in pork skin and duck skin, potentially influencing food safety and quality. This study contributed to an enhanced understanding of the microbial mechanisms underlying the alterations in microbial communities during high-temperature processing of pork skin and duck skin, with significant implications for ensuring food safety and developing effective cooking techniques.
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Affiliation(s)
- Dan Hai
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (D.H.); (H.J.); (Z.M.); (M.Q.); (T.X.); (L.S.)
- Henan Engineering Technology Research Center of Food Processing and Circulation Safety Control, Zhengzhou 450002, China
| | - Haisheng Jiang
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (D.H.); (H.J.); (Z.M.); (M.Q.); (T.X.); (L.S.)
| | - Ziheng Meng
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (D.H.); (H.J.); (Z.M.); (M.Q.); (T.X.); (L.S.)
| | - Mingwu Qiao
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (D.H.); (H.J.); (Z.M.); (M.Q.); (T.X.); (L.S.)
- Henan Engineering Technology Research Center of Food Processing and Circulation Safety Control, Zhengzhou 450002, China
| | - Tian Xu
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (D.H.); (H.J.); (Z.M.); (M.Q.); (T.X.); (L.S.)
| | - Lianjun Song
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (D.H.); (H.J.); (Z.M.); (M.Q.); (T.X.); (L.S.)
- Henan Engineering Technology Research Center of Food Processing and Circulation Safety Control, Zhengzhou 450002, China
| | - Xianqing Huang
- College of Food Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (D.H.); (H.J.); (Z.M.); (M.Q.); (T.X.); (L.S.)
- Henan Engineering Technology Research Center of Food Processing and Circulation Safety Control, Zhengzhou 450002, China
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Inactivation of Bacillus cereus endospores on black pepper by pulsed superheated steam system. Food Res Int 2023; 167:112649. [PMID: 37087238 DOI: 10.1016/j.foodres.2023.112649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 01/09/2023] [Accepted: 02/25/2023] [Indexed: 03/05/2023]
Abstract
In this study, a superheated steam (SHS) system was constructed to inactivate Bacillus cereus endospores on the surface of black pepper, and continuous and pulsed treatment was applied to compare sporicidal effects. Additionally, inactivation mechanisms were analyzed to investigate the differences between pulsed and continuous SHS treatments. SHS at 250 °C and 300 °C for 1 min achieved more than a 3 log reduction, whereas SHS at 200 °C for 1 min achieved less than 2 log reduction in the number of endospores. In addition, higher microbicidal effects were confirmed with pulsed SHS treatment with a shorter duty ratio. To elucidate the inactivation mechanisms, inner membrane damage (dipicolinic acid release), intracellular enzyme activities, and DNA integrity were measured after 300 °C SHS pulsed or continuous treatments. After pulsed SHS treatment for up to 20 s, intracellular enzymes were inactivated more rapidly than after continuous treatment, and more DPA was released after 40 s of treatment, indicating that enzyme inactivation occurred prior to inner membrane damage, and pulsed treatment accelerated this mode of action. DNA integrity was significantly lower after 60 s of pulsed or continuous treatment; however, there was no difference in between pulsed and continuous treatments. Our results provide fundamental insights for the sterilization of black pepper by SHS treatment in food industries.
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Wu T, Zachariah MR. Silver ferrite: a superior oxidizer for thermite-driven biocidal nanoenergetic materials. RSC Adv 2019; 9:1831-1840. [PMID: 35516147 PMCID: PMC9059743 DOI: 10.1039/c8ra08997c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 12/13/2018] [Indexed: 11/21/2022] Open
Abstract
Silver-containing oxidizers are of interest as biocidal components in energetic application such as thermites due to their biocidal agent delivery. In this study, AgFeO2, was evaluated as an oxidizer in aluminum-based thermite system. This novel oxidizer AgFeO2 particles were prepared via a wet-chemistry method and its structure, morphologies and thermal behavior were investigated using X-ray diffraction, scanning electron microscopy, thermogravimetric analysis and differential scanning calorimetry, and time-resolved temperature-jump time-of-flight mass spectrometry. The results indicate the decomposition pathways of AgFeO2 vary with heating rates from a two-step at low heating rate to a single step at high heating rate. Ignition of Al/AgFeO2 occurs at a temperature just above the oxygen release temperature that is very similar to Al/Fe2O3 and Al/CuO. However, with a pressurization rate three times of Al/CuO, Al/AgFeO2 yields a comparable result as to Al/hollow-CuO or Al/KClO4/CuO, with a simpler preparation method. The post combustion products demonstrated that the Al/AgFeO2 thermite reaction produces a fine dispersion of elemental nanosized silver particles which coats the larger alumina particles and is thus bioavailable.
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Affiliation(s)
- Tao Wu
- Department of Chemistry and Biochemistry, Department of Chemical and Biomolecular Engineering, University of Maryland College Park MD 20742 USA
| | - Michael R Zachariah
- Department of Chemistry and Biochemistry, Department of Chemical and Biomolecular Engineering, University of Maryland College Park MD 20742 USA
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Trunet C, Carlin F, Coroller L. Investigating germination and outgrowth of bacterial spores at several scales. Trends Food Sci Technol 2017. [DOI: 10.1016/j.tifs.2017.03.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Warda AK, Tempelaars MH, Boekhorst J, Abee T, Nierop Groot MN. Identification of CdnL, a Putative Transcriptional Regulator Involved in Repair and Outgrowth of Heat-Damaged Bacillus cereus Spores. PLoS One 2016; 11:e0148670. [PMID: 26849219 PMCID: PMC4746229 DOI: 10.1371/journal.pone.0148670] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 01/21/2016] [Indexed: 12/27/2022] Open
Abstract
Spores are widely present in the environment and are common contaminants in the food chain, creating a challenge for food industry. Nowadays, heat treatments conventionally applied in food processing may become milder to comply with consumer desire for products with higher sensory and nutritional values. Consequently subpopulations of spores may emerge that are sublethally damaged rather than inactivated. Such spores may germinate, repair damage, and eventually grow out leading to uncontrolled spoilage and safety issues. To gain insight into both the behaviour of damaged Bacillus cereus spores, and the process of damage repair, we assessed the germination and outgrowth performance using OD595 measurements and microscopy combined with genome-wide transcription analysis of untreated and heat-treated spores. The first two methods showed delayed germination and outgrowth of heat-damaged B. cereus ATCC14579 spores. A subset of genes uniquely expressed in heat-treated spores was identified with putative roles in the outgrowth of damaged spores, including cdnL (BC4714) encoding the putative transcriptional regulator CdnL. Next, a B. cereus ATCC14579 cdnL (BC4714) deletion mutant was constructed and assessment of outgrowth from heat-treated spores under food relevant conditions showed increased damage compared to wild type spores. The approach used in this study allows for identification of candidate genes involved in spore damage repair. Further identification of cellular parameters and characterisation of the molecular processes contributing to spore damage repair may provide leads for better control of spore outgrowth in foods.
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Affiliation(s)
- Alicja K. Warda
- TI Food and Nutrition, Wageningen, The Netherlands
- Laboratory of Food Microbiology, Wageningen University, Wageningen, The Netherlands
- Wageningen UR Food & Biobased Research, Wageningen, The Netherlands
| | - Marcel H. Tempelaars
- Laboratory of Food Microbiology, Wageningen University, Wageningen, The Netherlands
| | - Jos Boekhorst
- TI Food and Nutrition, Wageningen, The Netherlands
- NIZO Food Research B.V., Ede, The Netherlands
| | - Tjakko Abee
- TI Food and Nutrition, Wageningen, The Netherlands
- Laboratory of Food Microbiology, Wageningen University, Wageningen, The Netherlands
| | - Masja N. Nierop Groot
- TI Food and Nutrition, Wageningen, The Netherlands
- Wageningen UR Food & Biobased Research, Wageningen, The Netherlands
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Cattani F, Barth VC, Nasário JSR, Ferreira CAS, Oliveira SD. Detection and quantification of viable Bacillus cereus group species in milk by propidium monoazide quantitative real-time PCR. J Dairy Sci 2016; 99:2617-2624. [PMID: 26830746 DOI: 10.3168/jds.2015-10019] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 09/23/2015] [Indexed: 11/19/2022]
Abstract
The Bacillus cereus group includes important spore-forming bacteria that present spoilage capability and may cause foodborne diseases. These microorganisms are traditionally evaluated in food using culturing methods, which can be laborious and time-consuming, and may also fail to detect bacteria in a viable but nonculturable state. The purpose of this study was to develop a quantitative real-time PCR (qPCR) combined with a propidium monoazide (PMA) treatment to analyze the contamination of UHT milk by B. cereus group species viable cells. Thirty micrograms per milliliter of PMA was shown to be the most effective concentration for reducing the PCR amplification of extracellular DNA and DNA from dead cells. The quantification limit of the PMA-qPCR assay was 7.5 × 10(2) cfu/mL of milk. One hundred thirty-five UHT milk samples were analyzed to evaluate the association of PMA to qPCR to selectively detect viable cells. The PMA-qPCR was able to detect B. cereus group species in 44 samples (32.6%), whereas qPCR without PMA detected 78 positive samples (57.8%). Therefore, the PMA probably inhibited the amplification of DNA from cells that were killed during UHT processing, which avoided an overestimation of bacterial cells when using qPCR and, thus, did not overvalue potential health risks. A culture-based method was also used to detect and quantify B. cereus sensu stricto in the same samples and showed positive results in 15 (11.1%) samples. The culture method and PMA-qPCR allowed the detection of B. cereus sensu stricto in quantities compatible with the infective dose required to cause foodborne disease in 3 samples, indicating that, depending on the storage conditions, even after UHT treatment, infective doses may be reached in ready-to-consume products.
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Affiliation(s)
- Fernanda Cattani
- Laboratório de Imunologia e Microbiologia, Faculdade de Biociências, PUCRS, Porto Alegre, RS, Brazil
| | - Valdir C Barth
- Laboratório de Imunologia e Microbiologia, Faculdade de Biociências, PUCRS, Porto Alegre, RS, Brazil
| | - Jéssica S R Nasário
- Laboratório de Imunologia e Microbiologia, Faculdade de Biociências, PUCRS, Porto Alegre, RS, Brazil
| | - Carlos A S Ferreira
- Laboratório de Imunologia e Microbiologia, Faculdade de Biociências, PUCRS, Porto Alegre, RS, Brazil
| | - Sílvia D Oliveira
- Laboratório de Imunologia e Microbiologia, Faculdade de Biociências, PUCRS, Porto Alegre, RS, Brazil.
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Xing Y, Li A, Felker DL, Burggraf LW. Nanoscale structural and mechanical analysis of Bacillus anthracis spores inactivated with rapid dry heating. Appl Environ Microbiol 2014; 80:1739-49. [PMID: 24375142 PMCID: PMC3957622 DOI: 10.1128/aem.03483-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 12/21/2013] [Indexed: 11/20/2022] Open
Abstract
Effective killing of Bacillus anthracis spores is of paramount importance to antibioterrorism, food safety, environmental protection, and the medical device industry. Thus, a deeper understanding of the mechanisms of spore resistance and inactivation is highly desired for developing new strategies or improving the known methods for spore destruction. Previous studies have shown that spore inactivation mechanisms differ considerably depending upon the killing agents, such as heat (wet heat, dry heat), UV, ionizing radiation, and chemicals. It is believed that wet heat kills spores by inactivating critical enzymes, while dry heat kills spores by damaging their DNA. Many studies have focused on the biochemical aspects of spore inactivation by dry heat; few have investigated structural damages and changes in spore mechanical properties. In this study, we have inactivated Bacillus anthracis spores with rapid dry heating and performed nanoscale topographical and mechanical analysis of inactivated spores using atomic force microscopy (AFM). Our results revealed significant changes in spore morphology and nanomechanical properties after heat inactivation. In addition, we also found that these changes were different under different heating conditions that produced similar inactivation probabilities (high temperature for short exposure time versus low temperature for long exposure time). We attributed the differences to the differential thermal and mechanical stresses in the spore. The buildup of internal thermal and mechanical stresses may become prominent only in ultrafast, high-temperature heat inactivation when the experimental timescale is too short for heat-generated vapor to efficiently escape from the spore. Our results thus provide direct, visual evidences of the importance of thermal stresses and heat and mass transfer to spore inactivation by very rapid dry heating.
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Affiliation(s)
- Yun Xing
- Department of Engineering Physics, Air Force Institute of Technology, Wright-Patterson Air Force Base (WPAFB), Dayton, Ohio, USA
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, Tennessee, USA
| | - Alex Li
- Department of Engineering Physics, Air Force Institute of Technology, Wright-Patterson Air Force Base (WPAFB), Dayton, Ohio, USA
| | - Daniel L. Felker
- Department of Systems Engineering & Management, Air Force Institute of Technology, WPAFB, Dayton, Ohio, USA
| | - Larry W. Burggraf
- Department of Engineering Physics, Air Force Institute of Technology, Wright-Patterson Air Force Base (WPAFB), Dayton, Ohio, USA
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Reineke K, Mathys A, Heinz V, Knorr D. Mechanisms of endospore inactivation under high pressure. Trends Microbiol 2013; 21:296-304. [DOI: 10.1016/j.tim.2013.03.001] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 03/01/2013] [Accepted: 03/05/2013] [Indexed: 01/27/2023]
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Cattani F, Ferreira C, Oliveira S. The detection of viable vegetative cells of Bacillus sporothermodurans using propidium monoazide with semi-nested PCR. Food Microbiol 2013; 34:196-201. [DOI: 10.1016/j.fm.2012.12.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 11/12/2012] [Accepted: 12/26/2012] [Indexed: 11/26/2022]
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Kim YG, Lee JH, Cho MH, Lee J. Indole and 3-indolylacetonitrile inhibit spore maturation in Paenibacillus alvei. BMC Microbiol 2011; 11:119. [PMID: 21619597 PMCID: PMC3126691 DOI: 10.1186/1471-2180-11-119] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 05/27/2011] [Indexed: 12/26/2022] Open
Abstract
Background Bacteria use diverse signaling molecules to ensure the survival of the species in environmental niches. A variety of both Gram-positive and Gram-negative bacteria produce large quantities of indole that functions as an intercellular signal controlling diverse aspects of bacterial physiology. Results In this study, we sought a novel role of indole in a Gram-positive bacteria Paenibacillus alvei that can produce extracellular indole at a concentration of up to 300 μM in the stationary phase in Luria-Bertani medium. Unlike previous studies, our data show that the production of indole in P. alvei is strictly controlled by catabolite repression since the addition of glucose and glycerol completely turns off the indole production. The addition of exogenous indole markedly inhibits the heat resistance of P. alvei without affecting cell growth. Observation of cell morphology with electron microscopy shows that indole inhibits the development of spore coats and cortex in P. alvei. As a result of the immature spore formation of P. alvei, indole also decreases P. alvei survival when exposed to antibiotics, low pH, and ethanol. Additionally, indole derivatives also influence the heat resistance; for example, a plant auxin, 3-indolylacetonitrile dramatically (2900-fold) decreased the heat resistance of P. alvei, while another auxin 3-indoleacetic acid had a less significant influence on the heat resistance of P. alvei. Conclusions Together, our results demonstrate that indole and plant auxin 3-indolylacetonitrile inhibit spore maturation of P. alvei and that 3-indolylacetonitrile presents an opportunity for the control of heat and antimicrobial resistant spores of Gram-positive bacteria.
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Affiliation(s)
- Yong-Guy Kim
- School of Chemical Engineering, Yeungnam University, Gyeongsan, Gyeonsangbuk-do 712-749, Korea
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