Aflatoxin
Aflatoxins are various
Children are particularly vulnerable to aflatoxin exposure, which is linked to immune suppression, stunted growth,[6] delayed development,[7] aflatoxicosis,[8] food spoilage and liver cancer.[9] Some studies have reported an association between childhood stunting and aflatoxin exposure, although this link has not been consistently detected in all studies.[10][11] but could not be detected in all.[12][13] Furthermore, a causal relationship between childhood stunting and aflatoxin exposure has yet to be conclusively shown by epidemiological studies, though such investigations are underway.[14][15][16] Adults have a higher tolerance to exposure, but are also at risk. No animal species is known to be immune. Aflatoxins are among the most carcinogenic substances known.[17] After entering the body, aflatoxins may be metabolized by the liver to a reactive epoxide intermediate or hydroxylated to become the less harmful aflatoxin M1.
Aflatoxin poisoning most commonly results from ingestion, but the most toxic aflatoxin compound, B1, can permeate through the skin.[18]
The
The term "aflatoxin" is derived from the name of the species Aspergillus flavus, in which some of the compounds first were discovered. A new disease was identified with unknown characteristics in England during the 1950s and 1960s, which increased turkey mortality. Later, aflatoxin was recognized in 1960 in England as a causative agent of the mysterious
Major types and their metabolites
Aflatoxin B1 is considered the most toxic and is produced by both Aspergillus flavus and Aspergillus parasiticus. Aflatoxin M1 is present in the fermentation broth of Aspergillus parasiticus, but it and aflatoxin M2 are also produced when an infected liver metabolizes aflatoxin B1 and B2.
- Aflatoxin B1 and B2 (AFB), produced by A. flavus and A. parasiticus
- Aflatoxin G1 and G2 (AFG), produced by some Group II A. flavus and Aspergillus parasiticus[23]
- Aflatoxin M1 (AFM1), metabolite of aflatoxin B1 in humans and animals (exposure in nglevels may come from a mother's milk)
- Aflatoxin M2, metabolite of aflatoxin B2 in milk of cattle fed on contaminated foods[24]
- Aflatoxicol (AFL): metabolite produced by breaking down the lactone ring
- Aflatoxin Q1 (AFQ1), major metabolite of AFB1 in in vitro liver preparations of other higher vertebrates[25]
AFM, AFQ, and AFL retain the possibility to become an epoxide. Nevertheless, they appear much less capable of causing mutagenesis than the unmetabolized toxin.[26]
Contamination conditions
Aflatoxins are produced by both Aspergillus flavus and Aspergillus parasiticus, which are common forms of 'weedy' molds widespread in nature. The presence of those molds does not always indicate that harmful levels of aflatoxin are present, but does indicate a significant risk. The molds can colonize and contaminate food before harvest or during storage, especially following prolonged exposure to a high-humidity environment, or to stressful conditions such as drought. Aflatoxin contamination is increasing in crops such as maize as a result of climate change creating better conditions for these molds.[27][28]
The native habitat of Aspergillus is in soil, decaying vegetation,
A study conducted in Kenya and Mali found that the predominant practices for drying and storage of maize were inadequate in minimizing exposure to aflatoxins.[32]
Organic crops, which are not treated with fungicides, may be more susceptible to contamination with aflatoxins.[33]
Prevention
A primary means of limiting risk from aflatoxins in the food supply is
There is very limited evidence to show that agricultural and nutritional education can reduce exposure to aflatoxin in low to middle income countries.[34]
Pathology
No animal species is known to be immune to the acute toxic effects of aflatoxins. Adult humans have a high tolerance for aflatoxin exposure and rarely succumb to acute aflatoxicosis,[35] but children are particularly affected, and their exposure can lead to stunted growth and delayed development, in addition to all the symptoms mentioned below.[7]
High-level aflatoxin exposure produces an acute
Chronic, subclinical exposure does not lead to symptoms so dramatic as acute aflatoxicosis. Chronic exposure increases the risk of developing liver and gallbladder cancer,[36] as aflatoxin metabolites may intercalate into DNA and alkylate the bases through epoxide moiety. This is thought to cause mutations in the p53 gene, an important gene in preventing cell cycle progression when there are DNA mutations, or signaling apoptosis (programmed cell death). These mutations seem to affect some base pair locations more than others, for example, the third base of codon 249 of the p53 gene appears to be more susceptible to aflatoxin-mediated mutations than nearby bases.[37] As with other DNA-alkylating agents, Aflatoxin B1 can cause immune suppression, and exposure to it is associated with an increased viral load in HIV positive individuals.[38][39]
The expression of aflatoxin-related diseases is influenced by factors such as species, age, nutrition, sex, and the possibility of concurrent exposure to other toxins. The main target organ in mammals is the liver, so aflatoxicosis primarily is a hepatic disease. Conditions increasing the likelihood of aflatoxicosis in humans include limited availability of food, environmental conditions that favour mould growth on foodstuffs, and lack of regulatory systems for aflatoxin monitoring and control.[40]
A regular diet including
There is no specific antidote for aflatoxicosis. Symptomatic and supportive care tailored to the severity of the liver disease may include intravenous fluids with dextrose, active vitamin K, B vitamins, and a restricted, but high-quality protein diet with adequate carbohydrate content.
In other animals
In dogs, aflatoxin has potential to lead to liver disease. Low levels of aflatoxin exposure require continuous consumption for several weeks to months in order for signs of liver dysfunction to appear.[42] Some articles have suggested the toxic level in dog food is 100–300 ppb and requires continuous exposure or consumption for a few weeks to months to develop aflatoxicosis.[43] No information is available to suggest that recovered dogs will later succumb to an aflatoxin-induced disease.
Turkeys are extremely susceptible to aflatoxicosis. Recent studies have revealed that this is due to the efficient
Some studies on pregnant hamsters showed a significant relationship between exposure of aflatoxin B1 (4 mg/kg, single dose) and the appearance of developmental anomalies in their offspring.[46]
In 2005, Diamond Pet Foods discovered aflatoxin in a product manufactured at their facility in Gaston, South Carolina.[47][48] In 23 states, Diamond voluntarily recalled 19 products formulated with corn and manufactured in the Gaston facility. Testing of more than 2,700 finished product samples conducted by laboratories confirmed that only two date codes of two adult dog formulas had the potential to be toxic.[49]
In December 2020 and January 2021, Midwestern Pet Foods recalled dog food that contained fatal levels of aflatoxin.[50] As many as 70 dogs had died from aflatoxin poisoning by January 12, 2021.[51]
Detection in humans
There are two principal techniques that have been used most often to detect levels of aflatoxin in humans.
The first method is measuring the AFB1-guanine adduct in the urine of subjects. The presence of this breakdown product indicates exposure to aflatoxin B1 during the past 24 hours. This technique measures only recent exposure, however. Due to the half-life of this metabolite, the level of AFB1-guanine measured may vary from day to day, based on diet, it is not ideal for assessing long-term exposure.
Another technique that has been used is a measurement of the AFB1-albumin adduct level in the blood serum. This approach provides a more integrated measure of exposure over several weeks or months.
List of outbreaks
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International sources of commercial
- 1960 Outbreak of Turkey ‘X’ disease in England and Aflatoxin discovery
- 1961 Identified Aspergillus flavus associated with toxicity of groundnuts
- 1962 Studies conducted on physicochemical properties of aflatoxins, Aflatoxin B and G identified in TLC analysis, and Isolation and synthesis of crystalline aflatoxins.
- 1963 Aflatoxin B2, G1, and G2 were identified and chemically characterized as Difurocoumarin derivatives
- 1965 FDA approved the first regulation on aflatoxins 30 μg/kg
- 1966 Milk toxins were designated as AFM1 and AFM2 and AFM1 was detected in Milk, Urine, Kidney, and liver
- 1973 Poland: 10 died following the opening of the tomb of Casimir IV Jagiellon, which contained aflatoxin-producing molds.[57]
- 2004 Kenya: acute outbreak of aflatoxicosis resulting from ingestion of contaminated maize, 125 confirmed deaths. [58]
- February–March 2013: Romania, Serbia, Croatia imported into western Europe – 2013 aflatoxin contamination.
- February 2013: Iowa contamination.[59]
- 2014 (ongoing): Nepal and Bangladesh, neonatal exposures, found in umbilical cord blood.[60]
- 2019 Kenya: five brands of maize flour recalled due to contamination.[61]
- 2021 USA: Contamination of pet food manufactured by Midwestern Pet Food, causing the deaths of at least 70 dogs.[62]
- 2021 Sri Lanka: contaminated coconut oil released for public consumption by local government.[63]
- 2024 South Africa: The National Consumer Commission recalled various peanut butter brands due to contamination
See also
- Aflatoxin total synthesis
- 2013 aflatoxin contamination
- Mycotoxins in animal feed
- Nixtamalization
- Sterigmatocystin, a related toxin
- Other ways in which aspergillus can cause disease in mammals:
Resources
- ISBN 978-1-80356-884-3, retrieved 2024-04-02
- ISBN 978-1-80356-884-3, retrieved 2024-04-02
- ^ https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/molds-food-are-they-dangerous
- ^ ISBN 978-1-898486-52-7.
- .
- S2CID 19262759.
- ^ ISBN 978-0-8247-2303-3.
- ^ "Aflatoxicosis". 30 September 2014.
- .
- S2CID 23510545.
- PMID 17576701.
- PMID 28212415.
- PMID 29544138.
- PMID 26602301.
- PMID 30588341.
- PMID 26634701.
- ISBN 978-0-691-07016-2.
- PMID 22749975.
- ^ "Guidance for Industry: Action Levels for Poisonous or Deleterious Substances in Human Food and Animal Feed". Food and Drug Administration. August 2000. Retrieved November 14, 2020.
- JSTOR 1587768.
- ISBN 978-1-80356-884-3, retrieved 2024-04-02
- ^ J. Varga, J.C. Frisvad, R.A. Samson: "Two new aflatoxin producing species, and an overview of Aspergillus section Flavi", Stud Mycol. 2011 Jun 30; 69(1): 57–80. doi: 10.3114/sim.2011.69.05
- PMID 11273679. Archived from the originalon 2021-01-26. Retrieved 2018-12-29.
- ^ Aflatoxin M2 product page from Fermentek
- ISBN 978-0-8493-4904-1.
- PMID 9705898.
- .
- PMID 27066906.
- ^ "Risk of aflatoxin contamination increases with hot and dry growing conditions | Integrated Crop Management". crops.extension.iastate.edu. Retrieved 2021-06-13.
- ^ "Storing nuts at a low temperature (refrigeration) reduces aflatoxin levels and mold and yeast counts for 3–6 months | News | Postharvest – Fruits, Vegetables and Ornamentals". www.postharvest.biz. Retrieved 2021-06-13.
- .
- CIMMYT, the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Directorate of Groundnut Research and other organizations. It sought to provide evidence of the cost-effectiveness of aflatoxin risk-reduction strategies along maize and groundnut value chainsin Africa, and to understand what prevented adoption of these control strategies.
- PMID 23766719.
- PMID 32270495.
- ^ PMID 15531656.
- PMID 26010638.
- PMID 8397412.
- PMID 31534557.
- ^ "Common food fungus can accelerate onset of AIDS". digitaljournal.com. September 1, 2013.
- ISBN 978-1-904455-53-0.
- PMID 16762476.
- PMID 12619837.
- PMID 3444619.
- PMID 20707407.
- PMID 21616088.
- ISBN 9780323148498.
- ^ FDA Inspection Report-Diamond Gaston SC Plant 12/21/2005-1/19/2006.
- ^ 2005 Recall, FDA
- ^ AKC Standard Article Contaminated Diamond Pet Food Products and 'Best By' Dates Narrowed Akcstandard.com Archived July 7, 2011, at the Wayback Machine
- ^ Medicine, Center for Veterinary (2021-01-12). "FDA Alert: Certain Lots of Sportmix Pet Food Recalled for Potentially Fatal Levels of Aflatoxin". FDA.
- ^ Tyko, Kelly. "Dog food recall expands: More than 70 dogs have died and 80 pets sick after eating Sportsmix pet food". USA TODAY. Retrieved 2021-01-13.
- ISBN 978-1-80356-884-3, retrieved 2024-04-10
- PMID 20629398.
- ^ PMID 19338351.
- ^ PMID 20235534.
- .
- ^ Staff (19 May 2014). "Gdy otwarto grób królewski, zaczęła działać klątwa Jagiellończyka" [When the royal tomb was opened, the Jagiellon curse began its work]. Gazeta Krakowska. Retrieved 18 January 2023.
- PMID 17308181.
- ^ "Dog food recall underscores toxic danger in drought-hit U.S. corn". Reuters. February 25, 2013.
- ^ "Aflatoxin threat in Nepal, Bangladesh". SciDev.Net South Asia. 2014-12-17. Archived from the original on 2016-03-03. Retrieved 2016-10-17.
- ^ Mutahi B (2019-11-15). "How safe is Kenya's staple food?". Retrieved 2019-11-15.
- ^ "US pet food recalled after 70 dogs die and others fall sick". BBC News. 2021-01-14. Retrieved 2021-01-14.
- ^ "Coconut oil stocks containing aflatoxins in market". themorning.lk. 2021-03-26. Retrieved 2021-03-26.