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Sun Y, Shao L, Liu Y, Zou B, Wang H, Li X, Dai R. Inactivation of Bacillus cereus spores by ohmic heating: Efficiency and changes of spore biological properties. Int J Food Microbiol 2024; 421:110784. [PMID: 38897047 DOI: 10.1016/j.ijfoodmicro.2024.110784] [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: 12/18/2023] [Revised: 05/13/2024] [Accepted: 06/02/2024] [Indexed: 06/21/2024]
Abstract
Bacillus cereus spores pose a significant concern during food processing due to their high resistance to environmental stress. Ohmic heating (OH) is an emerging and alternative heating technology with potential for inactivating such spores. This study evaluated the inactivation effects and the biological property changes of Bacillus cereus spores during OH treatments. OH effectively inactivated spores in milk, orange juice, broth, rice soup, and buffer solution in less time than oil bath heating (OB). A decrease in NaCl content improved spore inactivation at the same temperature. Spores were more sensitive to acid at 80-85 °C with OH treatment. Furthermore, OH at 10 V/cm and 50 Hz could reduce the spore resistance and inhibit an increase in spore hydrophobicity and spore aggregation. Both heating methods resulted in significant dipicolinic acid (DPA) leakage and damage to the cortex and inner membranes of the spores. However, OH at 10 V/cm and 50 Hz had the lowest DPA leakage and inflicted the least damage to the inner membrane. The damage to the spore's inner membrane was considered the primary reason for inactivation by OB and OH treatments. Still, OH at 10 V/cm and 50 Hz might also block the germination or outgrowth of treated spores or cause damage to the spore core.
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Affiliation(s)
- Yingying Sun
- College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Lele Shao
- College of Tea & Food Science and Technology, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei 230036, PR China
| | - Yana Liu
- College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Bo Zou
- College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Han Wang
- College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Xingmin Li
- College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Ruitong Dai
- College of Food Science and Nutritional Engineering, China Agricultural University, No.17 Qinghua East Road, Haidian District, Beijing 100083, PR China.
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Yang S, Piao Y, Li X, Mu D, Ji S, Wu R, Wu J. A new decontamination method for Bacillus subtilisin pasteurized milk: Thermosonication treatment. Food Res Int 2023; 163:112291. [PMID: 36596196 DOI: 10.1016/j.foodres.2022.112291] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 11/26/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022]
Abstract
Thermosonication (TS) is a novel and viable technique employed to replace conventional thermal processing. TS treatment combined with pasteurization was used to kill the residual heat-resistant Bacillus in pasteurized milk and extend the shelf life of pasteurized milk and compared with High Temperture Shoort Time (HTST) pasteurization to study its decontamination effect on Bacillus subtilis and the quality of treated milk. The results showed that after 40 kHz, 240 W, 25 min ultrasonic treatment and 50 °C heating decontamination treatment, the number of B. subtilis in the medium and milk medium decreased by 4.17 log CFU/mL and 4.09 log CFU/mL respectively. The results of cell membrane permeability showed that the leakage of DNA and protein in the HTST-TS group increased by 52.3 % and 34 %, respectively, when compared to that in the HTST group. In addition, transmission electron microscopy (TEM) analysis showed that the bacterial cell membrane of the HTST-TS group swelled up, the cell wall was ruptured, and the cell content was accumulated in the cells. The results showed that HTST-TS treatment significantly inhibited the activities of ATPase (47 %), succinate dehydrogenase (SDH) (68.6 %), and malate dehydrogenase (MDH) (54.4 %). The physical and chemical sensory evaluation of milk treated with HTST-TS showed that HTST-TS treatment could improve the L* value (2.24 %), zeta potential (64.19 %), and colloidal particle size (14.49 %) of milk but had no significant effect on oral sensitivity. In conclusion, this study provides new insights, which may be helpful in implementing this new combined decontamination method in the dairy industry to improve the quality of pasteurized milk and extend the its shelf life.
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Affiliation(s)
- Shanshan Yang
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, Liaoning Province; Shenyang Key Laboratory of Microbial Fermentation Technology Innovation, Shenyang 110866, PR China
| | - Yuqiong Piao
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, Liaoning Province; Shenyang Key Laboratory of Microbial Fermentation Technology Innovation, Shenyang 110866, PR China
| | - Xinfei Li
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, Liaoning Province; Liaoning Engineering Research Center of Food Fermentation Technology, Shenyang 110866, Liaoning Province, PR China
| | - Delun Mu
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, Liaoning Province; Shenyang Key Laboratory of Microbial Fermentation Technology Innovation, Shenyang 110866, PR China
| | - Shuaiqi Ji
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, Liaoning Province; Shenyang Key Laboratory of Microbial Fermentation Technology Innovation, Shenyang 110866, PR China
| | - Rina Wu
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, Liaoning Province; Liaoning Engineering Research Center of Food Fermentation Technology, Shenyang 110866, Liaoning Province, PR China.
| | - Junrui Wu
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, Liaoning Province; Shenyang Key Laboratory of Microbial Fermentation Technology Innovation, Shenyang 110866, PR China.
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Dikec J, Pacheco M, Lavaud M, Winckler P, Perrier-Cornet JM. Uptake of UVc induced photoproducts of dipicolinic acid by Bacillus subtilis spores - Effects on the germination and UVc resistance of the spores. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2022; 236:112569. [PMID: 36152351 DOI: 10.1016/j.jphotobiol.2022.112569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/05/2022] [Accepted: 09/14/2022] [Indexed: 06/16/2023]
Abstract
Dipicolinic acid (DPA) is a specific molecule of bacterial spores which is essential to their resistance to various stresses such as ultraviolet (UV) exposure and to their germination. DPA has a particular photochemistry that remains imperfectly understood. In particular, due to its ability to absorb UVc radiation, it is likely to form in vitro a wide variety of photoproducts (DPAp) of which only about ten have been recently identified. The photochemical reactions resulting in DPAp, especially those inside the spores, are still poorly understood. Only one of these DPAp, which probably acts as a photosensitizer of DNA upon exposure to UVc, has been identified as having an impact on spores. However, as UVc is required to form DPAp, it is difficult to decouple the overall effect of UVc exposure from the possible effects of DPAp alone. In this study, DPAp were artificially introduced into the spores of the FB122 mutant strain of Bacillus subtilis, one that does not produce DPA. These experiments revealed that some DPAp may play a positive role for the spore. These benefits are visible in an improvement in spore germination rate and kinetics, as well as in an increase in their resistance to UVc exposure.
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Affiliation(s)
- J Dikec
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France
| | - M Pacheco
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France
| | - M Lavaud
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France; Dimacell Imaging Facility, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1 Esplanade Erasme, 21000 Dijon, France
| | - P Winckler
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France; Dimacell Imaging Facility, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1 Esplanade Erasme, 21000 Dijon, France
| | - J M Perrier-Cornet
- UMR Procédés Alimentaires et Microbiologiques, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1, Esplanade Erasme, 21000 Dijon, France; Dimacell Imaging Facility, L'Institut Agro Dijon, Université de Bourgogne Franche-Comté, 1 Esplanade Erasme, 21000 Dijon, France.
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Relevant safety aspects of raw milk for dairy foods processing. ADVANCES IN FOOD AND NUTRITION RESEARCH 2022; 100:211-264. [PMID: 35659353 DOI: 10.1016/bs.afnr.2022.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The concern with food safety in the milk chain begins with the quality of the raw milk. Due to the health hazard that this food can carry when contaminated, the focus of studies has turned to microbiological and chemical contaminants that may be present in raw milk. There is an essential concern about conventional pathogens (Shiga toxin-producing Escherichia coli, Salmonella spp., Listeria monocytogenes, Campylobacter spp., Salmonella spp., and coagulase-positive Staphylococcus spp.) and emerging pathogens (Arcobacter butzleri, Yersinia enterocolitica, Mycobacterium avium ssp. paratuberculosis, Helicobacter pylori, and Cronobacter sakazakii) found in raw milk and dairy products. In addition, a growing public health issue has been raised regarding antimicrobial-resistant pathogens and commensal strains found in milk and dairy products. The antibiotic residues in milk can also damage health, such as allergies, and cause technological problems in dairy products processing. This health issue extends to other chemical contaminants such as heavy metals, pesticides, polycyclic aromatic hydrocarbons, melamine, dioxins, polychlorinated biphenyls, plasticizers, and additives in milk and dairy products. Other chemical substances formed by microorganisms are also of high importance, such as biogenic amines and mycotoxins. Therefore, this chapter aimed to revise and discuss relevant biological and chemical risks to ensure the safety and quality of raw milk and dairy products.
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