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Cai H, Pei S, Zhang Y, Liu R, Lu S, Li B, Dong J, Wang Q, Zhu X, Ji H. Construction of a dynamic model to predict the growth of Staphylococcus aureus and the formation of enterotoxins during Kazak cheese maturation. Food Microbiol 2023; 112:104234. [PMID: 36906305 DOI: 10.1016/j.fm.2023.104234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 02/03/2023] [Accepted: 02/03/2023] [Indexed: 02/07/2023]
Abstract
Staphylococcus aureus is a common pathogen found in cheese whose Staphylococcal enterotoxins (SE) are the main pathogenic factors that cause food poisoning. The objective of this study was to construct two models to evaluate the safety of Kazak cheese products in terms of composition, changes in S. aureus inoculation amount, Aw, fermentation temperature during processing, and growth of S. aureus in the fermentation stage. A total of 66 experiments comprised of five levels of inoculation amount (2.7-4 log CFU/g), five levels of Aw (0.878-0.961), and six levels of fermentation temperature (32-44 °C) were performed to confirm the growth of S. aureus and the presence of SE limit conditions. Two artificial neural networks (ANN) successfully described the relationship between the assayed conditions and the growth kinetic parameters (maximum growth rates and lag times) of the strain. The good fitting accuracy (R2 values were 0.918 and 0.976, respectively) showed that the ANN was appropriate. Experimental results showed fermentation temperature had the greatest influence on the maximum growth rate and lag time, followed by the Aw and inoculation amount. Furthermore, a probability model was built to predict the production of SE by logistic regression and neural network under the assayed conditions, which proved to be concordant in 80.8-83.8% of the cases with the observed probabilities. The maximum total number of colonies predicted by the growth model in all combinations detected with SE exceeded 5 log CFU/g. Within the range of variables, the minimum Aw for predicting SE production was 0.938, and the minimum inoculation amount for predicting SE production was 3.22 log CFU/g. Additionally, as competition between S. aureus and lactic acid bacteria (LAB) occurs in the fermentation stage, higher fermentation temperatures are conducive to the growth of LAB, which can reduce the risk of S. aureus producing SE. This study can help manufacturers to make decisions on the most appropriate production parameters for Kazak cheese products and to prevent S. aureus growth and SE production.
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Affiliation(s)
- Huixue Cai
- School of Food Science and Technology, Shihezi University, 832003, China
| | - Sijie Pei
- College of Food Science and Technology, Northwest University, Xi'an, 710069, China
| | - Yan Zhang
- School of Food Science and Technology, Shihezi University, 832003, China; Zhoukou Vocational College of Arts and Science, Zhoukou, Henan, 466000, China
| | - Rongrong Liu
- School of Food Science and Technology, Shihezi University, 832003, China
| | - Shiling Lu
- School of Food Science and Technology, Shihezi University, 832003, China
| | - Baokun Li
- School of Food Science and Technology, Shihezi University, 832003, China
| | - Juan Dong
- School of Food Science and Technology, Shihezi University, 832003, China
| | - Qingling Wang
- School of Food Science and Technology, Shihezi University, 832003, China
| | - Xinrong Zhu
- School of Food Science and Technology, Shihezi University, 832003, China
| | - Hua Ji
- School of Food Science and Technology, Shihezi University, 832003, China.
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Zhang Z, Song Y, Ma L, Huang K, Liang Z. Co-Occurrence of <i>Staphylococcus aureus</i> and Ochratoxin A in Pasteurized Milk. Toxins (Basel) 2022; 14:toxins14100718. [PMID: 36287986 PMCID: PMC9612031 DOI: 10.3390/toxins14100718] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 10/10/2022] [Accepted: 10/17/2022] [Indexed: 11/23/2022] Open
Abstract
Pathogens and mycotoxins are serious public health risks for humans and food safety in milk. This study concentrated on detecting <i>Staphylococcus aureus</i> and Ochratoxin A (OTA) in 210 pasteurized milk from ten urban Beijing districts to suggest the co-occurrence of <i>S. aureus</i> with toxin-producing genes and OTA in milk and the possible risk. <i>S. aureus</i> was identified by physiological and biochemical experiments and molecular biology experiments, and enterotoxin genes were identified by PCR. OTA was detected by LC-MS/MS. The study found 29 isolates of <i>S. aureus</i>, of which 17.24% had the sea gene encoding enterotoxin A. OTA was detected in 31 out of 120 samples and the maximum amount of detection was 18.8 μg/kg. The results of this study indicate that when failing to guarantee the cold chain, the presence of <i>S. aureus</i> with enterotoxin genes in milk will present a risk to food safety. Furthermore, the high detection rates and levels of OTA in milk suggest that OTA is a hidden risk. The co-occurrence of <i>S. aureus</i> and OTA in milk is a food safety concern and there is a need to control the occurrence of these two biohazards in milk.
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Affiliation(s)
- Zhenzhen Zhang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Yanmin Song
- Beijing JTM International Food Co., Ltd., Beijing 101400, China
| | - Liyan Ma
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
- The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing 100083, China
| | - Kunlun Huang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
- The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing 100083, China
- Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Zhihong Liang
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
- The Supervision, Inspection and Testing Center of Genetically Modified Organisms, Ministry of Agriculture, Beijing 100083, China
- Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
- Correspondence: ; Tel.: +86-010-6273-7055
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Florianova M, Korena K, Juricova H. Whole-genome analysis of methicillin-resistant and methicillin-sensitive Staphylococcus aureus in dry-fermented salami. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2022.114042] [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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Carneiro Aguiar RA, Ferreira FA, Dias RS, Nero LA, Miotto M, Verruck S, De Marco I, De Dea Lindner J. Graduate Student Literature Review: Enterotoxigenic potential and antimicrobial resistance of staphylococci from Brazilian artisanal raw milk cheeses. J Dairy Sci 2022; 105:5685-5699. [DOI: 10.3168/jds.2021-21634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 03/22/2022] [Indexed: 11/19/2022]
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5
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Liu C, Shen Y, Yang M, Chi K, Guo N. Hazard of Staphylococcal Enterotoxins in Food and Promising Strategies for Natural Products against Virulence. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:2450-2465. [PMID: 35170308 DOI: 10.1021/acs.jafc.1c06773] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Staphylococcal enterotoxins (SEs) secreted by Staphylococcus aureus frequently contaminate food and cause serious foodborne diseases but are ignored during food processing and even cold-chain storage. Notably, SEs are stable and resistant to harsh sterilization environments, which can induce more serious hazards to public health than the bacterium itself. Therefore, it is necessary to develop promising strategies to control SE contamination in food and improve food safety. Natural products not only have various pharmaceutical properties, such as antimicrobial and antitoxin activities, but they are also eco-friendly, safe, nutritive, and barely drug-resistant. Here, the hazards of SEs and the promising natural compounds with different inhibitory mechanisms are summarized and classified. The key points of future research and applications for natural products against bacterial toxin contamination in food are also prospected. Overall, this review may provide enlightening insights for screening effective natural compounds to prevent foodborne diseases caused by bacterial toxins.
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Affiliation(s)
- Chunmei Liu
- College of Food Science and Engineering, Jilin University, 5333 Xi'an Road, Changchun, Jilin 130062, People's Republic of China
| | - Yong Shen
- College of Food Science and Engineering, Jilin University, 5333 Xi'an Road, Changchun, Jilin 130062, People's Republic of China
| | - Meng Yang
- College of Food Science and Engineering, Jilin University, 5333 Xi'an Road, Changchun, Jilin 130062, People's Republic of China
| | - Kunmei Chi
- College of Food Science and Engineering, Jilin University, 5333 Xi'an Road, Changchun, Jilin 130062, People's Republic of China
| | - Na Guo
- College of Food Science and Engineering, Jilin University, 5333 Xi'an Road, Changchun, Jilin 130062, People's Republic of China
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Etter D, Jenni C, Tasara T, Johler S. Mild Lactic Acid Stress Causes Strain-Dependent Reduction in SEC Protein Levels. Microorganisms 2021; 9:1014. [PMID: 34066749 PMCID: PMC8151770 DOI: 10.3390/microorganisms9051014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/30/2021] [Accepted: 05/05/2021] [Indexed: 12/12/2022] Open
Abstract
Staphylococcal enterotoxin C (SEC) is a major cause of staphylococcal food poisoning in humans and plays a role in bovine mastitis. Staphylococcus aureus (S. aureus) benefits from a competitive growth advantage under stress conditions encountered in foods such as a low pH. Therefore, understanding the role of stressors such as lactic acid on SEC production is of pivotal relevance to food safety. However, stress-dependent cues and their effects on enterotoxin expression are still poorly understood. In this study, we used human and animal strains harboring different SEC variants in order to evaluate the influence of mild lactic acid stress (pH 6.0) on SEC expression both on transcriptional and translational level. Although only a modest decrease in sec mRNA levels was observed under lactic acid stress, protein levels showed a significant decrease in SEC levels for some strains. These findings indicate that post-transcriptional modifications can act in SEC expression under lactic acid stress.
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Affiliation(s)
- Danai Etter
- Institute for Food Safety and Hygiene, University of Zurich, 8057 Zurich, Switzerland; (D.E.); (T.T.)
- Laboratory of Food Microbiology, Institute for Food, Nutrition and Health (IFNH), ETH Zurich, 8092 Zurich, Switzerland;
| | - Céline Jenni
- Laboratory of Food Microbiology, Institute for Food, Nutrition and Health (IFNH), ETH Zurich, 8092 Zurich, Switzerland;
| | - Taurai Tasara
- Institute for Food Safety and Hygiene, University of Zurich, 8057 Zurich, Switzerland; (D.E.); (T.T.)
| | - Sophia Johler
- Institute for Food Safety and Hygiene, University of Zurich, 8057 Zurich, Switzerland; (D.E.); (T.T.)
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Grispoldi L, Karama M, Armani A, Hadjicharalambous C, Cenci-Goga BT. Staphylococcus aureus enterotoxin in food of animal origin and staphylococcal food poisoning risk assessment from farm to table. ITALIAN JOURNAL OF ANIMAL SCIENCE 2021. [DOI: 10.1080/1828051x.2020.1871428] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
| | - Musafiri Karama
- Department of Paraclinical Sciences, University of Pretoria, Onderstepoort, South Africa
| | - Andrea Armani
- Department of Veterinary Sciences, University of Pisa, Pisa, Italy
| | | | - Beniamino T. Cenci-Goga
- Department of Veterinary Medicine, Perugia, Italy
- Department of Paraclinical Sciences, University of Pretoria, Onderstepoort, South Africa
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8
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Ishizaki N, Kamata Y, Furuhata K, Sugita-Konishi Y. [Behavior of Staphylococcus aureus and Staphylococcal Enterotoxins A and Q in Scrambled Eggs]. Food Hygiene and Safety Science (Shokuhin Eiseigaku Zasshi) 2020; 61:132-137. [PMID: 33012767 DOI: 10.3358/shokueishi.61.132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Staphylococcal food poisoning (SFP) is caused by Staphylococcus aureus, and its typical symptom of vomiting is evoked by staphylococcal enterotoxins (SEs). SEs are classified as classical and new types. SEQ is a new-type enterotoxin predicted to have a high potential risk for SFP. To elucidate the correlation between the number of S. aureus cells and the production of SEs as well as classical and new-type enterotoxins in the food environment, the numbers of S. aureus strain cells carrying sea and seq genes and the production of SEA and SEQ protein were examined under 3 pHs values (pH 6.0, 7.0 and 8.0) and 2 NaCl concentrations (0.5 and 1.0%) conditions. The experiments were performed at 25℃, resembling the setting of scrambled eggs at room temperature after cooking. By 24 hr after incubation, the cell number in the scrambled egg was ≥107/10 g, reaching 109/10 g by 48 hr under all conditions. The productions of both SEA and SEQ were detected in the scrambled egg under all conditions by 48 h. SEQ was detected from 24 hr at all 3 pH values in the egg containing 1.0% NaCl, whereas in the egg containing 0.5% NaCl, it was detected from 24 hr at pH 6.0 and from 48 hr at other pHs. The SEQ production was consistently 100-1,000 times less than that of SEA. These results suggest that the new-type enterotoxin SEQ has the potential to evoke symptoms related to SFP following the consumption of egg products cooked under relative lower pH and water activity.
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Affiliation(s)
- Naoto Ishizaki
- School of Life and Environmental Sciences, Azabu University
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Elahi S, Fujikawa H. Effects of Lactic Acid and Salt on Enterotoxin A Production and Growth of Staphylococcus aureus. J Food Sci 2019; 84:3233-3240. [PMID: 31618461 DOI: 10.1111/1750-3841.14829] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 09/02/2019] [Accepted: 09/04/2019] [Indexed: 11/28/2022]
Abstract
Food poisoning caused by Staphylococcus aureus is responsible for staphylococcal enterotoxin (SE) produced in foods. Staphylococcal food poisoning is mostly caused by staphylococcal enterotoxin type A (SEA) among SEs. Growth/no growth for S. aureus under various environmental conditions was well studied with a logistic regression model so far. Recently we successfully described the boundaries of SEA production and growth of S. aureus in broth at various temperatures and salt concentrations with the model. In this study, the effects of lactic acid and salt on SEA production and growth of S. aureus was quantitatively studied. Consequently the boundaries of SEA production and growth of S. aureus cocktail in broth at various combinations of salt concentrations and pH values that were adjusted with lactic acid were successfully described with a logistic regression model. Here the cocktail was incubated in stationary culture at 30 °C and 10 °C. The maximum toxin production and cell growth of the cocktail were observed both at 5% salt in the pH range from 4.5 to 7.0. Also, the characteristics of individual strains of the cocktail in SEA production and growth at 30 °C and 10 °C were found to be specific to the strains. The present study revealed the effect of lactic acid and salt on SEA production and growth of S. aureus as well as the variety of SEA production and growth of S. aureus strains. These results would become useful information in food industry to prevent staphylococcal food poisoning. PRACTICAL APPLICATION: Boundaries of enterotoxin A production/no production and growth/no growth of staphylococcal cocktail at various combinations of pHs adjusted with lactic acid and salt concentrations were well described with a logistic regression model. The maximum toxin production and cell growth were observed both at 5% salt in the pH range from 4.5 to 7.0. A variety of the toxin production and cell growth were observed in terms of pH and salt concentration among individual strains of the cocktail.
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Affiliation(s)
- Shaheem Elahi
- The United Graduate School of Veterinary Sciences, Gifu Univ., Yanagido, Japan
| | - Hiroshi Fujikawa
- Laboratory of Veterinary Public Health, Faculty of Agriculture, Tokyo Univ. of Agriculture and technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, 183-8509, Japan
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10
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Zeaki N, Johler S, Skandamis PN, Schelin J. The Role of Regulatory Mechanisms and Environmental Parameters in Staphylococcal Food Poisoning and Resulting Challenges to Risk Assessment. Front Microbiol 2019; 10:1307. [PMID: 31244814 PMCID: PMC6581702 DOI: 10.3389/fmicb.2019.01307] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 05/27/2019] [Indexed: 11/29/2022] Open
Abstract
Prevention, prediction, control, and handling of bacterial foodborne diseases - an ongoing, serious, and costly concern worldwide - are continually facing a wide array of difficulties. Not the least due to that food matrices, highly variable and complex, can impact virulence expression in diverse and unpredictable ways. This review aims to present a comprehensive overview of challenges related to the presence of enterotoxigenic Staphylococcus aureus in the food production chain. It focuses on characteristics, expression, and regulation of the highly stable staphylococcal enterotoxins and in particular staphylococcal enterotoxin A (SEA). Together with the robustness of the pathogen under diverse environmental conditions and the range of possible entry routes into the food chain, this poses some of the biggest challenges in the control of SFP. Furthermore, the emergence of new enterotoxins, found to be connected with SFP, brings new questions around their regulatory mechanisms and expression in different food environments. The appearance of increasing amounts of antibiotic resistant strains found in food is also highlighted. Finally, potentials and limitations of implementing existing risk assessment models are discussed. Various quantitative microbial risk assessment approaches have attempted to quantify the growth of the bacterium and production of disease causing levels of toxin under various food chain and domestic food handling scenarios. This requires employment of predictive modeling tools, quantifying the spatiotemporal population dynamics of S. aureus in response to intrinsic and extrinsic food properties. In this context, the armory of predictive modeling employs both kinetic and probabilistic models to estimate the levels that potentiate toxin production, the time needed to reach that levels, and overall, the likelihood of toxin production. Following risk assessment, the main challenge to mitigate the risk of S. aureus intoxication is first to prevent growth of the organism and then to hamper the production of enterotoxins, or at least prevent the accumulation of high levels (e.g., >10-20 ng) in food. The necessity for continued studies indeed becomes apparent based on the challenges to understand, control, and predict enterotoxin production in relation to the food environment. Different types of food, preservatives, processing, and packaging conditions; regulatory networks; and different staphylococcal enterotoxin-producing S. aureus strains need to be further explored to obtain more complete knowledge about the virulence of this intriguing pathogen.
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Affiliation(s)
- Nikoleta Zeaki
- Division of Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
| | - Sophia Johler
- Institute for Food Safety and Hygiene, University of Zurich, Zurich, Switzerland
| | - Panagiotis N. Skandamis
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Athens, Greece
| | - Jenny Schelin
- Division of Applied Microbiology, Department of Chemistry, Lund University, Lund, Sweden
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Wu H, Zhao Y, Du Y, Miao S, Liu J, Li Y, Caiyin Q, Qiao J. Quantitative proteomics of Lactococcus lactis F44 under cross-stress of low pH and lactate. J Dairy Sci 2018; 101:6872-6884. [DOI: 10.3168/jds.2018-14594] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/13/2018] [Indexed: 12/12/2022]
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12
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Gunvig A, Andresen MS, Jacobsen T, Borggaard C. Staphtox predictor - A dynamic mathematical model to predict formation of Staphylococcus enterotoxin during heating and fermentation of meat products. Int J Food Microbiol 2018; 285:81-91. [PMID: 30071496 DOI: 10.1016/j.ijfoodmicro.2018.07.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 06/14/2018] [Accepted: 07/22/2018] [Indexed: 11/26/2022]
Abstract
Existing growth models for S. aureus predict growth in relation to temperature, aw/NaCl and pH, and the assessment of probable Staphylococcus enterotoxin (SE) formation is based solely on the number of S. aureus. However, during the production of meat products such as fermented sausages and semi-processed hams, growth of S. aureus is a critical control point in HACCP plans. There is a need to develop a model that evaluates the safety of the product regarding SE formation in relation to the product composition, changes in pH or temperature during the processing and the number of S. aureus in the final product. The objective of the present work is to develop a mathematical model that predicts both the increase in the number of S. aureus and whether SE formation is possible in different meat product processes. A total of 78 experiments were carried out in a meat model system. The experiments covered a range of different temperatures (10-40 °C), pH (4.6-6.0), water phase salt (WPS) (2.2-5.6%) and Sodium nitrite concentrations (0-150 ppm). The meat model system was inoculated with approximately 103 CFU/g of a multi-strain cocktail and incubated at the different temperatures. The cocktail consisted of three strains of S. aureus producing the Staphylococcus enterotoxins A to D (SEA to SED) and a methicillin-resistant strain producing SEG, SEI, SEM, SEN, SEO and SEU. Enumeration of S. aureus was performed several times during the incubation, SE was extracted from samples with >5 log CFU/g, and the SEA-E content was analysed by an ELISA method. Maximum growth rates and lag times calculated from microbiological data, together with temperature, pH, WPS and Sodium nitrite, were used to develop a SE and a growth model. The growth model was developed by training a neural network and the SE model based on logistic regression. The SE and growth models were validated on separate data sets (N = 200 SE model, N = 63 growth model) including both dynamic and static conditions. The SE model predicted all occurrences of toxin formation in the validation data sets. The growth model is a fail-safe model and the prediction errors are comparable to laboratory reproducibility. In conclusion, the models are applicable for predicting the increase in S. aureus and for evaluating if SE formation is likely during processing of meat products. The models are available to producers and other interested parties at www.dmripredict.dk.
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Affiliation(s)
- A Gunvig
- Danish Technological Institute, DMRI, Gregersensvej 9, DK-2630 Taastrup, Denmark.
| | - M S Andresen
- Danish Technological Institute, DMRI, Gregersensvej 9, DK-2630 Taastrup, Denmark
| | - T Jacobsen
- Danish Technological Institute, DMRI, Gregersensvej 9, DK-2630 Taastrup, Denmark
| | - C Borggaard
- Danish Technological Institute, DMRI, Gregersensvej 9, DK-2630 Taastrup, Denmark
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Schelin J, Susilo YB, Johler S. Expression of Staphylococcal Enterotoxins under Stress Encountered during Food Production and Preservation. Toxins (Basel) 2017; 9:E401. [PMID: 29244757 PMCID: PMC5744121 DOI: 10.3390/toxins9120401] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 12/12/2017] [Accepted: 12/14/2017] [Indexed: 12/24/2022] Open
Abstract
Staphylococcal food poisoning (SFP) is the most prevalent cause of food-borne intoxications worldwide. Consumption of enterotoxins preformed in food causes violent vomiting and can be fatal in children and the elderly. While being repressed by competing bacteria in most matrices, Staphylococcus aureus benefits from crucial competitive advantages in foods with high osmolarity or low pH. During recent years, the long-standing belief in the feasibility of assessing SFP risk based on colony-forming units of S. aureus present in food products has been disproven. Instead, researchers and food business operators are acutely aware of the imminent threat arising from unforeseeable enterotoxin production under stress conditions. This paradigm shift led to a variety of new publications enabling an improved understanding of enterotoxin expression under stress conditions encountered in food. The wealth of data provided by these studies is extremely diverse, as it is based on different methodological approaches, staphylococcal strains, stressors, and enterotoxins. Therefore, in this review, we aggregated and critically evaluated the complex findings of these studies, to provide readers with a current overview of the state of research in the field.
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Affiliation(s)
- Jenny Schelin
- Applied Microbiology, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden.
| | - Yusak Budi Susilo
- Applied Microbiology, Department of Chemistry, Lund University, SE-221 00 Lund, Sweden.
| | - Sophia Johler
- Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Winterthurerstrasse 272, 8057 Zurich, Switzerland.
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14
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Zhang P, Kaur M, Bowman JP, Ratkowsky DA, Tamplin M. Effect of Environmental Factors on Intra-Specific Inhibitory Activity of Carnobacterium maltaromaticum. Microorganisms 2017; 5:E59. [PMID: 28906433 PMCID: PMC5620650 DOI: 10.3390/microorganisms5030059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 09/06/2017] [Accepted: 09/07/2017] [Indexed: 01/04/2023] Open
Abstract
Carnobacterium maltaromaticum is frequently associated with foods having extended shelf-life due to its inhibitory activity to other bacteria. The quantification of such inhibition interactions affected by various environmental factors is limited. This study investigated the effect of environmental factors relevant to vacuum-packaged beef on inhibition between two model isolates of C. maltaromaticum, D0h and D8c, specifically D8c sensitivity to D0h inhibition and D0h inhibitor production. The effects of temperature (-1, 7, 15, 25 °C), atmosphere (aerobic and anaerobic), pH (5.5, 6, 6.5), lactic acid (0, 25, 50 mM) and glucose (0, 0.56, 5.55 mM) on D8c sensitivity (diameter of an inhibition zone) were measured. The effects of pH, glucose, lactic acid and atmosphere on D0h inhibitor production were measured at 25 °C. Sensitivity of D8c was the highest at 15 °C, under aerobic atmosphere, at higher concentrations of undissociated lactic acid and glucose, and at pH 5.5 (p < 0.001). pH significantly affected D0h inhibitor production (p < 0.001), which was the highest at pH 6.5. The effect of lactic acid depended upon pH level; at relatively low pH (5.5), lactic acid decreased the production rate (arbitrary inhibition unit (AU)/mL/h). This study provides a quantitative description of intra-species interactions, studied in in vitro environments that are relevant to vacuum-packaged beef.
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Affiliation(s)
- Peipei Zhang
- Tasmanian Institute of Agriculture, Food Safety Centre, University of Tasmania, Private Bag 54, Hobart, Tasmania 7001, Australia.
| | - Mandeep Kaur
- Tasmanian Institute of Agriculture, Food Safety Centre, University of Tasmania, Private Bag 54, Hobart, Tasmania 7001, Australia.
| | - John P Bowman
- Tasmanian Institute of Agriculture, Food Safety Centre, University of Tasmania, Private Bag 54, Hobart, Tasmania 7001, Australia.
| | - David A Ratkowsky
- Tasmanian Institute of Agriculture, Food Safety Centre, University of Tasmania, Private Bag 54, Hobart, Tasmania 7001, Australia.
| | - Mark Tamplin
- Tasmanian Institute of Agriculture, Food Safety Centre, University of Tasmania, Private Bag 54, Hobart, Tasmania 7001, Australia.
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Fujikawa H, Nagaoka K, Arai K. Degradation of staphylococcal enterotoxin A by a Pseudomonas aeruginosa isolate from raw milk. Biosci Biotechnol Biochem 2017; 81:1436-1443. [PMID: 28417705 DOI: 10.1080/09168451.2017.1314755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Recently, we found that staphylococcal enterotoxin A (SEA)-producing Staphylococcus aureus strains produced SEA in raw milk with microbial contaminants at high temperatures like 40 °C only. Moreover, the concentration of SEA produced in raw milk gradually decreased after the peak. The reason(s) for SEA degradation in raw milk was studied in this study. Degradation of SEA spiked in raw milk was observed at 40 °C, but not at 25 °C. A Pseudomonas aeruginosa isolate from raw milk degraded SEA spiked in broth at 40 °C. A sample partially purified with a chromatographic method from culture supernatant of the isolate degraded SEA. Two main proteolytic bands were observed in the sample by zymographic analysis with casein. These results suggested that the SEA in raw milk might be degraded by a protease(s) produced by the P. aeruginosa isolate. This finding might be the first report on SEA degradation by a proteolytic enzyme(s) derived from Pseudomonas bacteria to our knowledge.
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Affiliation(s)
- Hiroshi Fujikawa
- a Faculty of Agriculture, Laboratory of Veterinary Public Health , Tokyo University of Agriculture and Technology , Tokyo , Japan
| | - Kentaro Nagaoka
- b Faculty of Agriculture, Laboratory of Veterinary Physiology , Tokyo University of Agriculture and Technology , Tokyo , Japan
| | - Katsuhiko Arai
- c Faculty of Agriculture, Sderoprotein and Leather Research Institute , Tokyo University of Agriculture and Technology , Tokyo , Japan
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16
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Sihto HM, Stephan R, Engl C, Chen J, Johler S. Effect of food-related stress conditions and loss of agr and sigB on seb promoter activity in S. aureus. Food Microbiol 2017; 65:205-212. [PMID: 28400004 DOI: 10.1016/j.fm.2017.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 02/01/2017] [Accepted: 03/06/2017] [Indexed: 10/20/2022]
Abstract
Staphylococcal enterotoxin B (SEB) causes staphylococcal food poisoning and is produced in up to ten times higher quantities than other major enterotoxins. While Staphylococcus aureus growth is often repressed by competing flora, the organism exhibits a decisive growth advantage under some stress conditions. So far, data on the influence of food-related stressors and regulatory mutations on seb expression is limited and largely based on laboratory strains, which were later reported to harbor mutations. Therefore, the aim of this study was to investigate the influence of stress and regulatory mutations on seb promoter activity. To this end, transcriptional fusions were created in two strains, USA300 and HG003, carrying different seb upstream sequences fused to a blaZ reporter. NaCl, nitrite, and glucose stress led to significantly decreased seb promoter activity, while lactic acid stress resulted in significantly increased seb promoter activity. Loss of agr decreased seb promoter activity and loss of sigB increased promoter activity, with the magnitude of change depending on the strain. These results demonstrate that mild stress conditions encountered during food production and preservation can induce significant changes in seb promoter activity.
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Affiliation(s)
- Henna-Maria Sihto
- Institute for Food Safety and Hygiene, University of Zurich, Zurich, Switzerland
| | - Roger Stephan
- Institute for Food Safety and Hygiene, University of Zurich, Zurich, Switzerland
| | - Christoph Engl
- Skirball Institute of Biomolecular Medicine, New York University Medical Center New York, New York, USA
| | - John Chen
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore, Singapore
| | - Sophia Johler
- Institute for Food Safety and Hygiene, University of Zurich, Zurich, Switzerland; Skirball Institute of Biomolecular Medicine, New York University Medical Center New York, New York, USA.
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17
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Nunes MM, Caldas ED. Preliminary Quantitative Microbial Risk Assessment for Staphylococcus enterotoxins in fresh Minas cheese, a popular food in Brazil. Food Control 2017. [DOI: 10.1016/j.foodcont.2016.08.046] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Tetili F, Bendali F, Perrier J, Sadoun D. Anti-Staphylococcal Enterotoxinogenesis of Lactococcus lactis in Algerian Raw Milk Cheese. Food Technol Biotechnol 2017. [PMID: 29540985 DOI: 10.17113/ftb.55.04.17.5105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Staphylococcus aureus is a potential pathogen contaminating raw milk and dairy products, where it is able to produce thermostable enterotoxins that can cause staphylococcal food poisoning. This study was undertaken to investigate the inhibitory activity of a Lactococcus lactis strain (isolated from milk) on S. aureus growth and staphylococcal enterotoxin A (SEA) production. In the presence of L. lactis, the number of the pathogen decreased significantly (p<0.05) after 6 h of incubation in a laboratory medium and milk (3 log CFU/mL reduction compared to pure cultures). SEA concentration was reduced by 79% in the co-cultures. S. aureus was unable to reach population levels permitting SEA production in the cheese inoculated with L. lactis during 32 days of storage. In contrast, during the same period, it attained 7 log CFU/g in the cheese manufactured without the lactococcal strain, a level which permitted SEA detection in the cheese extracts. However, this enterotoxin was never detected in the cheese harbouring L. lactis. These results demonstrate the anti-staphylococcal enterotoxinogenesis potential of the L. lactis strain and its usefulness in raw milk cheese biopreservation.
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Affiliation(s)
- Fatiha Tetili
- Applied Microbiology Laboratory, Life and Nature Sciences Faculty, Bejaia University, DZ-06000 Bejaia, Algeria
| | - Farida Bendali
- Applied Microbiology Laboratory, Life and Nature Sciences Faculty, Bejaia University, DZ-06000 Bejaia, Algeria
| | - Josette Perrier
- Paul Cézanne Aix-Marseille III University, Group Molecular Interactions Intestinal Mucosal Microbiote, ISM2-Biosciences UMR CNRS 6263, Faculty of Sciences,
FR-13397 Marseille Cedex 20, France
| | - Djamila Sadoun
- Applied Microbiology Laboratory, Life and Nature Sciences Faculty, Bejaia University, DZ-06000 Bejaia, Algeria
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Tango CN, Khan I, Park YS, Oh DH. Growth of Staphylococcus aureus in cooked ready-to-eat ground fish as affected by inoculum size and potassium sorbate as food preservative. Lebensm Wiss Technol 2016. [DOI: 10.1016/j.lwt.2016.03.048] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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20
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Growth behavior and temporal enterotoxin D expression of Staphylococcus aureus strains under glucose and lactic acid stress. Food Control 2016. [DOI: 10.1016/j.foodcont.2015.10.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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21
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Ding T, Yu YY, Hwang CA, Dong QL, Chen SG, Ye XQ, Liu DH. Modeling the Effect of Water Activity, pH, and Temperature on the Probability of Enterotoxin A Production by Staphylococcus aureus. J Food Prot 2016; 79:148-52. [PMID: 26735042 DOI: 10.4315/0362-028x.jfp-15-161] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The objectives of this study were to develop a probability model of Staphylococcus aureus enterotoxin A (SEA) production as affected by water activity (a(w)), pH, and temperature in broth and assess its applicability for milk. The probability of SEA production was assessed in tryptic soy broth using 24 combinations of a(w) (0.86 to 0.99), pH (5.0 to 7.0), and storage temperature (10 to 30°C). The observed probabilities were fitted with a logistic regression to develop a probability model. The model had a concordant value of 97.5% and concordant index of 0.98, indicating that the model satisfactorily describes the probability of SEA production. The model showed that a(w), pH, and temperature were significant factors affecting the probability of toxin production. The model predictions were in good agreement with the observed values obtained from milk. The model may help manufacturers in selecting product pH and a(w) and storage temperatures to prevent SEA production.
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Affiliation(s)
- Tian Ding
- Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China; Synergetic Innovation Center of Food Safety and Nutrition, Northeast Agricultural University, Harbin 150030, People's Republic of China.
| | - Yan-Yan Yu
- Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China
| | - Cheng-An Hwang
- U.S. Department of Agriculture, Agricultural Research Service, Residue Chemistry and Predictive Microbiology Research Unit, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA
| | - Qing-Li Dong
- Institute of Food Science and Engineering, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093, People's Republic of China
| | - Shi-Guo Chen
- Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China
| | - Xing-Qian Ye
- Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Fuli Institute of Food Science, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China
| | - Dong-Hong Liu
- Department of Food Science and Nutrition, Zhejiang Key Laboratory for Agro-Food Processing, Synergetic Innovation Center of Food Safety and Nutrition, Northeast Agricultural University, Harbin 150030, People's Republic of China; Fuli Institute of Food Science, Zhejiang University, Hangzhou, Zhejiang 310058, People's Republic of China.
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Tango CN, Hong SS, Wang J, Oh DH. Assessment of Enterotoxin Production and Cross-Contamination of Staphylococcus aureus between Food Processing Materials and Ready-To-Eat Cooked Fish Paste. J Food Sci 2015; 80:M2911-6. [PMID: 26556562 DOI: 10.1111/1750-3841.13143] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 10/05/2015] [Indexed: 10/22/2022]
Abstract
This study evaluated Staphylococcus aureus growth and subsequent staphylococcal enterotoxin A production in tryptone soy broth and on ready-to-eat cooked fish paste at 12 to 37 °C, as well as cross-contamination between stainless steel, polyethylene, and latex glove at room temperature. A model was developed using Barany and Roberts's growth model, which satisfactorily described the suitable growth of S. aureus with R(2)-adj from 0.94 to 0.99. Except at 12 °C, S. aureus cells in TSB presented a lag time lower (14.64 to 1.65 h), grew faster (0.08 to 0.31 log CFU/h) and produced SEA at lower cell density levels (5.65 to 6.44 log CFU/mL) compare to those inoculated on cooked fish paste with data of 16.920 to 1.985 h, 0.02 to 0.23 log CFU/h, and 6.19 to 7.11 log CFU/g, respectively. Staphylococcal enterotoxin type A (SEA) visual immunoassay test showed that primary SEA detection varied considerably among different storage temperature degrees and media. For example, it occurred only during exponential phase at 30 and 37 °C in TSB, but in cooked fish paste it took place at late exponential phase of S. aureus growth at 20 and 25 °C. The SEA detection test was negative on presence of S. aureus on cooked fish paste stored at 12 and 15 °C, although cell density reached level of 6.12 log CFU/g at 15 °C. Cross-contamination expressed as transfer rate of S. aureus from polyethylene surface to cooked fish paste surface was slower than that observed with steel surface to cooked fish paste under same conditions. These results provide helpful information for controlling S. aureus growth, SEA production and cross-contamination during processing of cooked fish paste.
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Affiliation(s)
- Charles Nkufi Tango
- Dept. of Food Science and Biotechnology, College of Biotechnology and Bioscience, Kangwon National Univ, Hyoja 2 dong, Chunchon, 200-701, Republic of Korea
| | - Sung-Sam Hong
- Korea Inst. Food Safety Management Accreditation, Bomun-ro 246, Jung-gu, Daejeon, 301-722, Korea
| | - Jun Wang
- College of Food Science and Engineering, Qingdao Agricultural Univ, No. 700, Changcheng Road, Chengyang, Qingdao, 266109, China
| | - Deog-Hwan Oh
- Dept. of Food Science and Biotechnology, College of Biotechnology and Bioscience, Kangwon National Univ, Hyoja 2 dong, Chunchon, 200-701, Republic of Korea
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Antibacterial and technological properties of Lactococcus lactis ssp. lactis KJ660075 strain selected for its inhibitory power against Staphylococcus aureus for cheese quality improving. Journal of Food Science and Technology 2015. [DOI: 10.1007/s13197-015-1845-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Friedman M, Rasooly R. Review of the inhibition of biological activities of food-related selected toxins by natural compounds. Toxins (Basel) 2013; 5:743-75. [PMID: 23612750 PMCID: PMC3705290 DOI: 10.3390/toxins5040743] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 04/05/2013] [Accepted: 04/16/2013] [Indexed: 11/17/2022] Open
Abstract
There is a need to develop food-compatible conditions to alter the structures of fungal, bacterial, and plant toxins, thus transforming toxins to nontoxic molecules. The term 'chemical genetics' has been used to describe this approach. This overview attempts to survey and consolidate the widely scattered literature on the inhibition by natural compounds and plant extracts of the biological (toxicological) activity of the following food-related toxins: aflatoxin B1, fumonisins, and ochratoxin A produced by fungi; cholera toxin produced by Vibrio cholerae bacteria; Shiga toxins produced by E. coli bacteria; staphylococcal enterotoxins produced by Staphylococcus aureus bacteria; ricin produced by seeds of the castor plant Ricinus communis; and the glycoalkaloid α-chaconine synthesized in potato tubers and leaves. The reduction of biological activity has been achieved by one or more of the following approaches: inhibition of the release of the toxin into the environment, especially food; an alteration of the structural integrity of the toxin molecules; changes in the optimum microenvironment, especially pH, for toxin activity; and protection against adverse effects of the toxins in cells, animals, and humans (chemoprevention). The results show that food-compatible and safe compounds with anti-toxin properties can be used to reduce the toxic potential of these toxins. Practical applications and research needs are suggested that may further facilitate reducing the toxic burden of the diet. Researchers are challenged to (a) apply the available methods without adversely affecting the nutritional quality, safety, and sensory attributes of animal feed and human food and (b) educate food producers and processors and the public about available approaches to mitigating the undesirable effects of natural toxins that may present in the diet.
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Affiliation(s)
- Mendel Friedman
- Produce Safety and Microbiology Research Unit, Agricultural Research Service, USDA, Albany, CA 94710, USA
| | - Reuven Rasooly
- Foodborne Contaminants Research Unit, Agricultural Research Service, USDA, Albany, CA 94710, USA; E-Mail:
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