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Misiou O, Ellouze M, Koutsoumanis K. Cardinal models to describe the effect of temperature and pH on the growth of Anoxybacillus flavithermus & Bacillus licheniformis. Food Microbiol 2023; 112:104230. [PMID: 36906302 DOI: 10.1016/j.fm.2023.104230] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/20/2023] [Accepted: 01/22/2023] [Indexed: 01/26/2023]
Abstract
Anoxybacillus flavithermus and Bacillus licheniformis are among the predominant spore-formers of heat-processed foods. To our knowledge, no systematic analysis of growth kinetic data of A. flavithermus or B. licheniformis is currently available. In the present study, the growth kinetics of A. flavithermus and B. licheniformis in broth at various temperature and pH conditions were studied. Cardinal models were used to model the effect of the above-mentioned factors on the growth rates. The estimated values for the cardinal parameters Tmin,Topt,Tmax,pHmin and pH1/2 for A. flavithermus were 28.70 ± 0.26, 61.23 ± 0.16 and 71.52 ± 0.32 °C, 5.52 ± 0.01 and 5.73 ± 0.01, respectively, while for B. licheniformis they were 11.68 ± 0.03, 48.05 ± 0.15, 57.14 ± 0.01 °C, 4.71 ± 0.01 and 5.670 ± 0.08, respectively. The growth behaviour of these spoilers was also investigated in a pea beverage at 62 and 49 °C, respectively, to adjust the models to this product. The adjusted models were further validated at static and dynamic conditions and demonstrated good performance with 85.7 and 97.4% of predicted populations for A. flavithermus and B. licheniformis, respectively, being within the -10%-10% relative error (RE) zone. The developed models can be useful tools in assessing the potential of spoilage of heat-processed foods including plant-based milk alternatives.
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Affiliation(s)
- Ourania Misiou
- Department of Food Science and Technology, Faculty of Agriculture, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - Mariem Ellouze
- Food Safety Research Department, Nestlé Research, PO BOX44, CH-1000 Lausanne 26, Switzerland
| | - Konstantinos Koutsoumanis
- Department of Food Science and Technology, Faculty of Agriculture, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.
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Martin NH, Evanowski RL, Wiedmann M. Invited review: Redefining raw milk quality-Evaluation of raw milk microbiological parameters to ensure high-quality processed dairy products. J Dairy Sci 2023; 106:1502-1517. [PMID: 36631323 DOI: 10.3168/jds.2022-22416] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 09/17/2022] [Indexed: 01/11/2023]
Abstract
Raw milk typically has little bacterial contamination as it leaves the udder of the animal; however, through a variety of pathways, it can become contaminated with bacteria originating from environmental sources, the cow herself, and contact with contaminated equipment. Although the types of bacteria found in raw milk are very diverse, select groups are particularly important from the perspective of finished product quality. In particular, psychrophilic and psychrotolerant bacteria that grow quickly at low temperatures (e.g., species in the genus Pseudomonas and the family Enterobacteriaceae) and produce heat-stable enzymes, and sporeforming bacteria that survive processing hurdles in spore form, are the 2 primary groups of bacteria related to effects on processed dairy products. Understanding factors leading to the presence of these important bacterial groups in raw milk is key to reducing their influence on processed dairy product quality. Here we examine the raw milk microbiological parameters used in the contemporary dairy industry for their utility in identifying raw milk supplies that will perform well in processed dairy products. We further recommend the use of a single microbiological indicator of raw milk quality, namely the total bacteria count, and call for the development of a whole-farm approach to raw milk quality that will use data-driven, risk-based tools integrated across the continuum from production to processing and shelf-life to ensure continuous improvement in dairy product quality.
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Affiliation(s)
- N H Martin
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14853.
| | - R L Evanowski
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14853
| | - M Wiedmann
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14853
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Meng L, Zhang R, Dong L, Hu H, Liu H, Zheng N, Wang J, Cheng J. Characterization and spoilage potential of Bacillus cereus isolated from farm environment and raw milk. Front Microbiol 2022; 13:940611. [PMID: 36177462 PMCID: PMC9514233 DOI: 10.3389/fmicb.2022.940611] [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: 05/10/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Bacillus cereus sensu lato (B. cereus sl) is important spoilage bacteria causing milk structure and flavor changes and is ubiquitous in the environment. This study addresses the biodiversity, toxicity, and proteolytic activity of B. cereus sl from 82 environmental samples and 18 raw bovine milk samples from a dairy farm in the region of Tianjin. In sum, 47 B. cereus sl isolates were characterized through biochemical tests, 16S rRNA gene sequencing, and panC gene analysis. Fourteen sequence types (STs) of B. cereus sl were found in raw bovine milk samples, and five new STs (ST2749, ST2750, ST2751, ST2752, and ST2753) were identified in this study. ST1150 was the dominant ST, associated with fecal, air, drinking water, teat skin, teat cup, and teat dip cup. The results of toxin gene analyses showed that 12.77% and 8.51% of isolates carried hblACD and nheABC operons, respectively. In addition, the detection rate of emetic cesB gene was 21.28%. B. cereus sl demonstrated high spoilage potentials even at 7°C, which has the proteolytic activity of 14.32 ± 1.96 μmol of glycine equivalents per ml. Proteolytic activities were significantly (p < 0.05) decreased after the heat treatment. The residual activity of protease produced at 7°C was significantly higher than that produced at 25°C and 37°C after treatment at 121°C for 10 s and 135°C for 5 s (p < 0.01). Together, the results provide insights into the characteristics of B. cereus sl from farm environment and raw bovine milk and revealed that B. cereus sl contamination should also be monitored in raw milk for ultra-high temperature (UHT) products. This knowledge illustrates that strict cleaning management should be implemented to control B. cereus sl and assure high-quality milk products.
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Affiliation(s)
- Lu Meng
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ruirui Zhang
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- College of Animal Science and Technology, Anhui Agricultural University, Hefei, China
| | - Lei Dong
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Precision Livestock and Nutrition Laboratory, Teaching and Research Centre (TERRA), Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Haiyan Hu
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huimin Liu
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Nan Zheng
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jiaqi Wang
- Laboratory of Quality and Safety Risk Assessment for Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- Key Laboratory of Quality & Safety Control for Milk and Dairy Products of Ministry of Agriculture and Rural Affairs, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
- *Correspondence: Jiaqi Wang
| | - Jianbo Cheng
- College of Animal Science and Technology, Anhui Agricultural University, Hefei, China
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Bacillus cereus in Dairy Products and Production Plants. Foods 2022; 11:foods11172572. [PMID: 36076758 PMCID: PMC9455733 DOI: 10.3390/foods11172572] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/09/2022] [Accepted: 08/18/2022] [Indexed: 11/16/2022] Open
Abstract
Spore-forming Bacillus cereus is a common contaminant of dairy products. As the microorganism is widespread in the environment, it can contaminate milk at the time of milking, but it can also reach the dairy products in each phase of production, storage and ripening. Milk pasteurization treatment is not effective in reducing contamination and can instead act as an activator of spore germination, and a potential associated risk still exists with the consumption of some processed foods. Prevalences and concentrations of B. cereus in milk and dairy products are extremely variable worldwide: in pasteurized milk, prevalences from 2% to 65.3% were reported, with concentrations of up to 3 × 105 cfu/g, whereas prevalences in cheeses ranged from 0 to 95%, with concentrations of up to 4.2 × 106 cfu/g. Bacillus cereus is also well known to produce biofilms, a serious concern for the dairy industry, with up to 90% of spores that are resistant to cleaning and are easily transferred. As the contamination of raw materials is not completely avoidable, and the application of decontamination treatments is only possible for some ingredients and is limited by both commercial and regulatory reasons, it is clear that the correct application of hygienic procedures is extremely important in order to avoid and manage the circulation of B. cereus along the dairy supply chain. Future developments in interventions must consider the synergic application of different mild technologies to prevent biofilm formation and to remove or inactivate the microorganism on the equipment.
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Jiang YH, Xin WG, Yang LY, Ying JP, Zhao ZS, Lin LB, Li XZ, Zhang QL. A novel bacteriocin against Staphylococcus aureus from Lactobacillus paracasei isolated from Yunnan traditional fermented yogurt: Purification, antibacterial characterization, and antibiofilm activity. J Dairy Sci 2022; 105:2094-2107. [PMID: 35180941 DOI: 10.3168/jds.2021-21126] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 11/05/2021] [Indexed: 01/05/2023]
Abstract
Staphylococcus aureus and its biofilm have emerged as a significant threat to the safety of dairy products. In recent years, lactic acid bacteria (LAB) bacteriocins have been widely acknowledged as the potential natural antibacterial substance in food biopreservation due to their excellent antibacterial effects. However, few LAB bacteriocins with antibacterial and antibiofilm activity against S. aureus have been reported in dairy products. In the present study, a novel bacteriocin LSX01 of Lactobacillus paracasei LS-6 isolated from a traditional fermented yogurt produced in Yunnan, China, was purified and characterized extensively. The LSX01 possessed a molecular weight of 967.49 Da and an AA sequence of LDQAGISYT. The minimum inhibitory concentration of LSX01 against S. aureus_45 was 16.90 μg/mL, which was close to or lower than the previously reported bacteriocins. The LSX01 exhibited an extensive antimicrobial spectrum against both gram-positive and gram-negative bacteria. Moreover, LSX01 exhibited excellent tolerance to heat and acid-base treatments, and sensitivity to the proteolytic enzymes, such as pepsin and proteinase K. Furthermore, the treatment of S. aureus_45 planktonic cells with LSX01 significantly reduced their metabolic activity and disrupted the cell membrane integrity. Scan electron microscopy results demonstrated that LSX01 induced cytoplasmic content leakage and cell deformation. Additionally, biofilm formation of S. aureus_45 was also significantly inhibited by LSX01. Overall, the results suggested that the novel LAB bacteriocin LSX01 possessed antibacterial activity and antibiofilm activity against S. aureus and, hence, could have potential for improving safety of dairy products.
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Affiliation(s)
- Yu-Hang Jiang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan Kunming 650500, China
| | - Wei-Gang Xin
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan Kunming 650500, China
| | - Lin-Yu Yang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan Kunming 650500, China
| | - Jian-Ping Ying
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan Kunming 650500, China
| | - Zi-Shun Zhao
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan Kunming 650500, China
| | - Lian-Bing Lin
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan Kunming 650500, China
| | - Xiu-Zhang Li
- State Key Laboratory of Plateau Ecology and Agriculture and Qinghai Academy of Animal and Veterinary Science, Qinghai University, Qinghai Xining 810000, China.
| | - Qi-Lin Zhang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Yunnan Kunming 650500, China.
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