Who can tell me the specific name of mold when food is moldy?

Mold is widely distributed in nature, and it is easy to pollute food because it can form various microspores. After food is contaminated by mold, it can not only lead to corruption and deterioration, but also some molds can produce toxins, which can cause mycotoxin poisoning in people and animals by eating by mistake.

Penicillium often grows in bread, leather, peel and clothes, with a wide variety, about 150 species. Spores are turquoise, so they are called Penicillium. The spores of Penicillium are attached to the spore stalk and arranged in a string, which is called conidia.

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(1) Salmonella food poisoning caused the most food poisoning. The main species are Salmonella typhimurium, Salmonella choleraesuis and Salmonella enteritidis. These bacteria are Gram-positive bacteria without spores and capsules, which mainly pollute fish, eggs and dairy products.

(2) Staphylococcus aureus food poisoning Staphylococcus aureus can produce exotoxin and enterotoxin. At a suitable temperature, the strain can produce a soluble protein enterotoxin with six different antigenicities of A, B, C, D, E and F. This enterotoxin has strong heat resistance, and its toxicity can only be destroyed at 2 18~248℃ for 30min. Milk and dairy products, cured meat, eggs and starchy foods are all easily contaminated by this bacteria.

(3) Conditional pathogenic bacteria Escherichia coli is an important normal flora in the intestine. Conditional pathogenic bacteria refer to serotype strains with specific antigenicity in Escherichia coli. Escherichia coli has three antigens: bacterial antigen (O), flagella antigen (H) and capsular antigen (K), and those with K antigen are more virulent than those without K antigen. K antigen can be divided into three categories: A, B and L. Conditional pathogens that can cause food poisoning include O 1 1: B 4, O 55: B5O, 26: B 6, O 157 and other serotypes.

(4) Vibrio parahaemolyticus food poisoning Vibrio parahaemolyticus is a halophilic, non-spore-producing, Gram-negative polymorphic cocci, which is mostly found in contaminated seafood and meat products, and other foods can also be contaminated when they come into contact with seafood. The cause of food poisoning is that this bacterium produces heat-resistant hemolytic toxin or enterotoxin similar to cholera toxin, or it is considered to be a mixed poisoning of toxin and infection.

(5) Clostridium botulinum food poisoning Clostridium botulinum is a gram-positive bacterium, which can form spores, has no capsule and flagella, and can produce an exotoxin botulinum toxin that is highly toxic to people and animals. It can be divided into seven serotypes: A, B, C (α, β), D, E, F and G, which have different pathogenicity to human beings. Botulinum toxin can be destroyed and unstable under high temperature, alkaline conditions and direct sunlight, but it is stable under acidic conditions. The poisoning is toxic poisoning, and the toxin acts on the cranial nucleus of the central nervous system, inhibiting the release of choline acetate and causing muscle paralysis. It is widely found in anaerobic soil, silt deposits, dust and animal manure in rivers, lakes and seas, and easily pollutes vegetables, fish, meat, beans and other foods rich in protein.

(6) Bacillus cereus food poisoning Bacillus cereus is a gram-positive bacterium that produces spores. Its poisoning is caused by a large number of live bacteria in food and enterotoxin produced by them. When the number of viable bacteria reaches (13~36 )× 10 6 /g(ml), it can cause disease. The bacterial content of (1.8 × 10 7) cells/ml (g) is often regarded as one of the indicators of food poisoning. Enterotoxins can be divided into heat-resistant and heat-labile. This kind of bacteria exists in soil, air, rotten grass, dust and so on. And the carrying rate of meat products, dairy products, vegetables and fruits is also high. It is also easy to pollute this kind of bacteria in various processing, transportation, storage and sales processes.

(8) Mold food poisoning is mainly caused by toxins produced by a few toxic molds. A strain or strain can produce several different toxins, and the same toxin can also be produced by different molds. Aspergillus and Penicillium are the main types of pollution, Caenorhabditis elegans and Mucor are the main types of meat pollution, and Aspergillus, Penicillium and Ephesus are the main types of feed pollution.

(9) Aflatoxin poisoning Aflatoxin poisoning is a kind of metabolic mixed product with similar structure produced by Aspergillus flavus and Aspergillus parasiticus, with 17 species. Its basic structure is difuran ring and coumarin, the former is the basic toxic structure and the latter is carcinogen. Aflatoxin is very stable, heat-resistant, does not decompose below the melting point (200℃ ~300℃), has strong toxicity, mainly damages the liver, causes hepatocyte necrosis, hemorrhage and bile duct hyperplasia, and has obvious carcinogenic effect. The mold producing aflatoxin mainly pollutes grain and its products, such as peanuts, peanut oil, rice and cottonseed, and milk and salted fish are also polluted.

(10) Wheat poisoning caused by scab is a poisoning phenomenon after eating wheat food affected by scab. The main pathogens causing wheat scab are Fusarium graminearum, Fusarium moniliforme, Fusarium oxysporum and Fusarium avenae. They can produce two mycotoxins, which can cause vomiting and zearalenone with estrogen effect.

(1 1) Yellow rice poisoning (yellow rice poisoning) refers to rice that turns yellow after being polluted by the metabolites of mold, which is called yellow rice. According to the different polluted molds, yellow rice can be divided into three types, namely, yellow rice transformed by Penicillium chrysogenum and yellow-green penicillin polluted by Penicillium chrysogenum. This toxin is very toxic, which can damage the nerves and lead to death. The second is that Penicillium citrinum turns yellow into rice, which is polluted by citrinin, the toxin of Penicillium citrinum, which mainly damages the kidney and causes substantial lesions. The third kind is Penicillium islandicum turning yellow into rice, which is polluted by luteoskyrin and islanditoxin, two toxins that poison the liver produced by Penicillium islandicum.

(12) ergot poisoning This poisoning is caused by eating wheat or wheat products containing ergot. The pathogen is ergot, which can form ergotamine, ergotoxine and ergotoxine, among which ergotamine can cause food poisoning, such as nausea, vomiting, abdominal pain, diarrhea, heart failure and coma. Different from chronic symptoms.

(13) food poisoning caused by toxic metabolites of mold, such as sugarcane mildew poisoning.

(14) Anthrax pathogens can cause anthrax, abdominal pain, vomiting and hematochezia after eating the meat of animals that died of anthrax by mistake. If pathogenic bacteria enter the blood, it is easy to form systemic sepsis. Brucellosis in cattle and pigs can also cause human diseases. Mycobacterium tuberculosis is another pathogen of human and animal diseases. Cattle are prone to this disease and are often found in sick milk.

Characteristics of mold toxin production

1) The toxin production of molds is limited to a few toxic molds, and only a part of the toxic strains produce toxins.

2) The virulence of virulent strains also showed variability and variability. After several generations of culture, the virulent strain can completely lose its virulence, while the non-virulent strain can produce virulence under certain conditions. Therefore, we should always consider this issue in practical work.

3) A strain or strain can produce several different toxins, and the same mycotoxin can also be produced by several molds.

4) The toxin-producing strains need certain conditions, mainly the type of substrate, moisture, temperature, humidity and air circulation.

3.2. 1 Aspergillus

Aspergillus has developed mycelium, which is multicellular and septate. Its asexual reproduction produces conidia, the conidiophore is unbranched, and the top of conidia expands into a spherical or wooden stick shape, which is called the apical sac. One or two petioles radiate from the apical sac, and a series of conidia are attached to the top of the petiole. Conidia have different colors, such as black, brown and yellow. The sexual generation of Aspergillus produces a closed capsule containing many spherical ascospores. Aspergillus is widely distributed in nature and has a strong ability to decompose organic matter. Some Aspergillus species, such as Aspergillus Niger, are widely used in food industry. At the same time, Aspergillus is also an important food contamination mold, which can lead to food spoilage and some strains can also produce toxins. The species that can produce toxins in Aspergillus are Aspergillus flavus (Aspergillus flavus), Aspergillus ochraceus (Aspergillus versicolor), Aspergillus fumigatus, Aspergillus nidulans (Aspergillus parasitica) and so on.

Penicillium

Penicillium mycelium is colorless or light-colored, with many branches and septa. From hypha to conidia with diaphragm, the top branches 1~2 times. These branches are called secondary branches and peduncle bases, where many peduncles are produced and conidia are found at the top of the peduncle. This structure is called a broom. Conidia can have different colors, such as cyan, grayish green, yellowish brown and so on. And the broom body are provided with a single wheel, a symmetrical multi-wheel and an asymmetrical multi-wheel. Only a few species of Penicillium form closed shells and produce ascospores. Penicillium is widely distributed and varied, and often exists in soil, grain, fruits and vegetables. Some species have high economic value and can produce a variety of enzymes and organic acids. On the other hand, Penicillium can cause spoilage of fruits, vegetables, grains and foods, and some species and strains can also produce toxins. For example, Penicillium islandicum (P.islandicum), Penicillium citrinum (P.citrinum), Penicillium yellowish green (P.citreo-viride), Penicillium rubrum (P.rubrum), Penicillium expansum (P.expansum), Penicillium arc, Penicillium expansum, Penicillium expansum and Penicillium expansum.

Fusarium

The aerial hyphae of this genus are developed or underdeveloped, and conidia can be divided into two types: large conidia with 3~7 septa, which are produced on the short claw-like processes of hyphae or in myxomycetes and have various shapes, such as sickle shape and spindle shape. Microconidia have 1~2 septa, which are oval and oval in shape and are produced on the conidiophore. The aerial hyphae, myxospores and sclerotia can be of various colors, and the substrate can be dyed in various colors.

Fusarium includes many species, most of which are plant pathogens and can produce toxins. Such as Fusarium graminearum, Fusarium graminearum, Fusarium poa, Fusarium aseptic, Fusarium oxysporum, Fusarium moniliforme, Fusarium moniliforme, Fusarium equisetum, Fusarium australis, Fusarium pink, etc.

Alternaria

The hyphae have transverse septa, creeping growth, short conidiophore, solitary or clustered, and most of them are unbranched. The conidia at the top of conidia vary in shape and size, including mulberry, oval and oval, and conidia are vertical and horizontal.

The septum and apex are elongated into beaks and multicellular. Spores are brown, and the number is constant and connected into chains. No sexual generation was found.

Alternaria alternata is widely distributed in soil and air, some of which are plant pathogens, which can cause deterioration of fruits and vegetables and produce toxins.

Other genera

Trichophyton farinosus, Trichoderma, lettuce, Aureobasidium nigrum, etc.

3.3 Main mycotoxins

3.3. 1 aflatoxin

Aflatoxin (AFT or AT for short) is the metabolite of Aspergillus flavus and Aspergillus parasiticus. All strains of parasitic Aspergillus can produce aflatoxin, but parasitic Aspergillus is rare in China. Aspergillus flavus is a common fungus in food and feed in China. Aflatoxin has attracted much attention because of its strong carcinogenicity. However, not all Aspergillus flavus are toxin-producing strains, and even toxin-producing strains can only produce toxins under suitable environmental conditions.

3.3. Characteristics of1.1aflatoxin

The chemical structure of aflatoxin is dihydrofuran and xanthone. Up to now, more than a dozen have been isolated, such as B 1, B2, G 1, G2, B2a, G2a, M 1, M2, P 1 and so on. Among them, B 1 is the most toxic and carcinogenic, and its toxicity is 0/00 times greater than that of potassium cyanide, second only to botulinum toxin, and it is the strongest mycotoxin. Carcinogenesis is stronger than all known chemical carcinogens and 75 times stronger than dimethylnitrosamine. Aflatoxin has the characteristics of heat resistance, its cracking temperature is 280℃, its solubility in water is very low, and it can be dissolved in oil and various organic solvents.

3.3. 1.2 conditions for aflatoxin production

The temperature range of Aspergillus flavus growth and toxin production is 12~42℃, the optimum temperature for toxin production is 33℃, and the optimum Aw value is 0.93~0.98. When Aspergillus flavus grows on corn, rice and wheat with water content of 18.5%, it begins to produce aflatoxin on the third day, reaches the peak on the tenth day, and then gradually decreases. When bacteria form spores, the toxins produced by mycelium are gradually discharged into the matrix. This delay in toxin production of Aspergillus flavus means that if the grain with high moisture content is dried within two days, the moisture content of the grain will drop below 13%, and even if Aspergillus flavus is polluted, it will not produce toxin.

Aflatoxin pollution can occur in a variety of foods, such as grains, oilseeds, fruits, dried fruits, condiments, milk and dairy products, vegetables, meat and so on. Among them, corn, peanuts and cottonseed oil are the most vulnerable to pollution, followed by rice, wheat, barley and beans. Grains such as peanuts and corn are suitable substrates for the growth of aflatoxin-producing strains and the production of aflatoxin. Peanut and corn may be contaminated by Aspergillus flavus before harvest, which makes mature peanuts not only pollute Aspergillus flavus but also carry toxins. When the ear of corn is ripe, not only Aspergillus flavus can be isolated from the ear, but also aflatoxin can be detected.

Table 8- 1 Allowable limits of aflatoxin in food and feed in various countries

Notes on the limit of aflatoxin B 1 in national food and feed at μg/kg.

China's national health standards for corn, peanuts, peanut oil, rice, other edible oil grains, bean fermented food and baby food < 20 < 10 < 50.

All Japanese foods are fed to 002040 chickens, calves, piglets, cows, other domestic animals and poultry.

General food peanut food peanut with shell 201525b1b2g1G2 total b 1b2g 1g 2 total B 1g2 total.

French food feed 050200 sheep, goats, adult sheep, adult pigs, chickens, cows and other livestock and poultry.

German food feed 10 < 50 ~ 200 (total B 1B2G 1G2) varies with different animal species.

Aflatoxin mainly produces two kinds of toxins, B 1 and B2. Therefore, B 1 is the representative of aflatoxin content determination. Aflatoxin is highly toxic, carcinogenic and widely distributed, which poses a great threat to people and animals. Therefore, all countries have formulated the maximum allowable dose in food and feed (Table 8- 1).

From the epidemiological investigation of liver cancer, it is found that the incidence of liver cancer is also high in areas with serious aflatoxin pollution in food and high actual intake of human body.

3.3.2 Yellow rice toxin

In the 1940s, yellow rice was found in rice in Japan. This kind of rice is yellow, so it is called yellow rice because it is polluted by fungi. Fungi that can cause rice to turn yellow are mainly Penicillium species. Yellow rice toxin can be divided into three categories:

3.3.2. 1 Penicillium flavum toxin

Rice was infected with Penicillium chrysogenum, and the water content was 14.6%. Yellow rice was formed at 12~ 13℃, with yellowish spots on the rice grains, and Penicillium chrysogenum toxin (yellow-green penicillin) was also produced. This toxin is insoluble in water and loses its toxicity when heated to 270℃. It has neurotoxicity and high toxicity. Poisoning is characterized by paralysis of the central nervous system, paralysis of the heart and the whole body, and finally death due to respiratory arrest.

Penicillium citrinum toxin in 3.3.2.2

After the rice was polluted by Penicillium citrinum, it turned yellow into rice, and the rice grains were yellow-green. White rice is easy to pollute Penicillium citri to form this yellow rice. Penicillium citrinum can produce citrinin, and Lan Qing, Penicillium flavum, Penicillium expansum, Penicillium punctatum, Penicillium cinerea and Aspergillus terreus can also produce citrinin. The toxin is insoluble in water and belongs to nephrotoxicity, which can cause renal enlargement, renal tubular dilatation and epithelial cell degeneration and necrosis in experimental animals.

Penicillium toxin in 3.3.2.3 Island

The rice contaminated by Penicillium islandicum turns yellow into rice, and the rice grains are yellow-brown ulcer spots. At the same time, it contains toxins produced by Penicillium islandicum, including huangtianjing, cyclophosphamide, Penicillium islandicum and Rhododendron. The first two toxins are hepatotoxic, and acute poisoning can lead to atrophy of animal liver. Chronic poisoning leads to liver fibrosis, cirrhosis or liver tumor, which can lead to liver cancer in rats.

fusarium toxin

According to the data of the Third Conference on Food Additives and Pollutants jointly held by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO), Fusarium toxin, like aflatoxin, is considered as the most dangerous natural food pollutant. Fusarium toxin is produced by Fusarium. Fusarium is widely distributed in nature and infects many crops. There are many kinds of Fusarium, which can produce Fusarium toxin and pose a great threat to human and animal health. More than a dozen Fusarium toxins have been found, which can be divided into the following three categories according to their chemical structures, namely monoterpenes, zearalenone and crotonolide.

3.3.3. 1 trichosporene

Trichosporene is a kind of toxin produced by Fusarium oxysporum, Fusarium graminearum, Fusarium pyriformis, Fusarium filamentous and other Fusarium. It is the most common Fusarium toxin that causes human and animal poisoning.

Among monoterpenes, deoxynivalenol (DON) is common in grain and feed in China. DON mainly exists in wheat grains with scab, and can also infect scab in corn, rice, broad bean and other crops. The pathogen of scab is Fusarium graminearum, and its asexual stage is Fusarium graminearum. The pathogen is suitable for growth and reproduction under the climatic conditions of continuous rainfall, high humidity and low temperature. If the wheat grains are infected at the milk maturity stage, the mature wheat grains will shrink and shrink, and there will be gray and pink mildew spots; If infected later, the wheat grains are still full, but the embryos are pink. DON, also known as emetic toxin, is soluble in water and has high thermal stability. Baking temperature 2 10℃, frying temperature 140℃ or boiling can only destroy 50%.

People often have symptoms such as nausea, dizziness, abdominal pain, vomiting and general weakness within one hour after eating DON-containing scab wheat (including 250g flour containing 10% diseased wheat) by mistake. A few cases were accompanied by diarrhea, facial flushing and headache. Feeding pigs with sick wheat leads to slow weight gain, yellowish fat, yellow liver and gallbladder bleeding after slaughter. The oral emetic dose of DON to dogs was 0.65438 0 mg/kg.

Zearalenone in 3.3.3.2

Zearalenone is a female estrus toxin. Female estrus syndrome occurs when animals eat feed containing this toxin. Fusarium graminearum, Fusarium flavum, Fusarium pink, Fusarium tricuspidatum and Fusarium equisetum can all produce zearalenone.

Zearalenone is insoluble in water, but soluble in alkaline aqueous solution. A large number of zearalenone can be obtained by inoculating Fusarium graminearum on corn culture medium, culturing at 25~28℃ for two weeks and then at 65438 02℃ for eight weeks. Sometimes wheat with scab may contain both DON and zearalenone. The feed containing zearalenone only showed symptoms at 1 ~ 5 mg/kg, and showed obvious symptoms at 500mg/kg. Zearalenone can also be detected in corn.

3.3.3.3 Butenolide (butenolide)

Butyrolactone is found in natural pasture. Cattle eating poisonous pasture will lead to hoof rot. The laboratory of Kashin-Beck disease of Harbin Medical University reported that crotonolide was found in corn produced in Kashin-Beck disease areas of Heilongjiang and Shaanxi. Butenolactone is produced by Fusarium oxysporum, Fusarium oxysporum, Pseudofusarium and Fusarium pyriformis, which is easily soluble in water and easily hydrolyzed in alkaline aqueous solution.

3.3.4 Poisoning by Aspergillus versicolor toxin

Aspergillus versicolor toxin (ST) is produced by Aspergillus versicolor and Aspergillus nidulans, and its basic structure is difuranyl ring and xanthone. Among them, aspergillus versicolor toxin IVa is the most toxic and insoluble in water, which can cause liver cancer, kidney cancer, skin cancer and lung cancer in animals, and its carcinogenicity is second only to aflatoxin. Because Aspergillus versicolor and Aspergillus nidulans often pollute grain and food, and more than 80% strains produce toxins, it is very important to study the etiology of liver cancer. It is easy to pollute aspergillus versicolor toxin in brown rice. After brown rice is processed into standard two meters, the toxin content can be reduced by 90%.

3.3.5 Aspergillus fuscus toxin

Aspergillus fuscus toxin is produced by Aspergillus fuscus, Penicillium, Penicillium arc and Huang Qing-producing mold. At present, there are two kinds of brown aspergillus toxin A and brown aspergillus toxin B, which are easily soluble in alkaline solution and can cause liver, kidney and other internal organs diseases of many animals, so they are called hepatotoxin or nephrotoxin, and can also cause lung diseases.

The suitable substrates for Aspergillus fuscus to produce toxin are corn, rice and wheat. The suitable temperature for toxin production is 20~30℃, and the Aw value is 0.997~0.953. Sometimes, Aspergillus fuscus A can be detected in grains and feed.

Penicillin toxin

Penicillin is mainly produced by Penicillium expansum, which is soluble in water and ethanol, unstable in alkaline solution and easy to be destroyed. The feed contaminated by Penicillium expansum can cause cattle poisoning, and the toxicity of Penicillium expansum toxin to mice is severe edema. Penicillium expansum produces a lot of toxins on wheat straw.

Penicillium expansum is an important mold in apple storage, which can rot apples. The apple juice produced by this rotten apple will contain Penicillium toxin. If apple juice is made of rotten apples with a rotten degree of 50%, the penicillin toxin can reach 20 ~ 40μ g/L.

Penicillic acid

Penicillic acid is produced by many kinds of molds, such as Penicillium papaya, Penicillium arc and Aspergillus fuscus. Very soluble in hot water and ethanol. Rats were injected subcutaneously with 1.0mg penicillic acid twice a week. After 64~67 weeks, fibroma appeared in the injection area, which proved that it had mutagenic effect on mice.

Penicillic acid was detected in corn, barley, beans, wheat, sorghum, rice and apples. Penicillic acid is formed below 20℃, so mildew of food stored at low temperature may pollute penicillic acid.

Alternaria toxin

Alternaria alternata is one of the common molds in grains, fruits and vegetables, which can cause spoilage of many fruits and vegetables. Alternaria alternata A variety of toxins are produced, mainly including four kinds: Alternaria phenol (AOH), Alternaria phenol methyl ether (AME), Alternaria alkene (ALT) and Alternaria acid (TeA). AOH and AME have teratogenic and mutagenic effects. Oral administration of 50~398mg/kg sodium tea salt to mice or rats can lead to gastrointestinal bleeding and death. The toxin produced by Alternaria alternata is very low in nature, and generally does not cause acute poisoning of human beings or animals, but its chronic toxicity is worthy of attention after long-term consumption. Tea was found in tomatoes and ketchup.

Human mycotoxin poisoning

Generally speaking, toxin-producing mold strains mainly grow on grain, fermented food and forage grass, but few directly produce toxins on animal foods such as meat, eggs and milk. Animals eat a lot of toxic forage grass, which will also cause various poisoning symptoms or remain in animal tissues and organs and milk, resulting in toxic animal food, and people will still cause mycotoxin poisoning after eating it.

Mycotoxin poisoning is related to people's eating habits, food types and living environment conditions, so mycotoxin poisoning often shows obvious local and seasonal characteristics, and some even have the characteristics of endemic diseases. For example, aflatoxin poisoning, yellow rice poisoning and scab wheat poisoning all have this characteristic. Furthermore, the clinical manifestations of mycotoxin poisoning are complex, ranging from acute poisoning caused by eating a small amount of food containing mycotoxin for a long time to chronic poisoning, and some will also induce canceration, deformity and mutation of genetic material in the body.

Food contaminated by mold, especially food contaminated by mycotoxin, is very harmful to human beings. As far as the world is concerned, it not only causes huge economic losses, but also causes serious diseases and even a large number of deaths. Not eating moldy and mycotoxin-containing foods can greatly reduce the incidence of cancer and avoid the occurrence of cancer.

Microorganisms on agricultural products

Microorganisms are abundant in various agricultural products, especially grain. According to its source, it can be divided into primary microbial flora and secondary microbial flora. Protozoan flora is formed by the long-term relationship between microorganisms and plants. They feed on the secretion of seeds, which is closely related to the life span and metabolic intensity of plants. Secondary microbial flora refers to those microorganisms that exist in soil and air and infect grains through various ways. Among the microorganisms in grain, mold is particularly harmful, which can produce 150 kinds of mycotoxins harmful to people and animals.