**4.2 Fungi**

Fungi can not only produce aflatoxins but also degrade aflatoxin. Such four fungal strains *Aspergillus niger*, *Eurotium herbariorum*, a *Rhizopus* sp., and nonaflatoxin-producing *A. flavus* were able to convert AFB1 to aflatoxicol-A (AFL-A); then AFL-A was converted to aflatoxicol-B (AFL-B) by the actions of medium components or organic acids produced from the fungi. Fungi *Penicillium raistrickii* NRRL 2038 could transform AFB1 to a new compound which is similar to AFB2.

Kusumaningtyas et al. found *Rhizopus oligosporus* was able to inhibit synthesis or to degrade AFB1 when cultured together with AFB1-producing fungi *A. flavus* [43].

#### **4.3 Yeasts and lactic acid bacteria**

The mechanism of degradation AFB by yeasts and lactic acid bacteria is due to their adhesion to cell wall components. However the role of yeasts and lactic acid bacteria on AFB is controversial. A few study showed there was no effect of yeasts and lactic bacteria upon aflatoxin [44]. The results showed that high levels of aflatoxins in raw maize would not be degraded during the fermentations in the processing of the west African traditional food "kenkey." Other studies reported very efficient aflatoxin reductions after fermentation. Chu et al. [45] reported that AFB1 concentration dramatically decrease during brewing process, which suggested that *S. cerevisiae* yeasts sorb mycotoxin. AFB1 was detoxified into a nontoxic new fluorescing compound corresponding to AFB2a during yogurt-making and dairy product fermentation [46, 47]. Drinking water with *S. cerevisiae* strain showed a positive protection effect on the relative weight of the liver and histopathological and biochemical parameters when giving the diets contaminated with AFB1 [48].

Lactic acid bacteria have been previously reported to possess antimycotoxigenic activities both in vitro and in vivo. The specific strains of lactic acid bacteria will bind selected dietary aflatoxin contaminants. The ability of 12 *Lactobacillus*, 5 *Bifidobacterium*, and 3 *Lactococcus* bacteria strains to bind AFB1 was investigated by Peltonen et al. [49]. Two *Lactobacillus* amylovorus strains and one *Lactobacillus rhamnosus* strain removed more than 50% AFB1 rapidly after a 72-hour incubation period. Another two lactic acid bacteria *Lactobacillus rhamnosus* strain GG (LBGG) and *L. rhamnosus* strain LC-705 (LC705) can significantly and very quickly remove approximately 80% AFB1 from culture media in both temperature- and bacteria concentration-dependent manner [50]. Kankaanpaa et al. [51] found that the binding of AFB1 to *L. rhamnosus* GG decreased its subsequent adhesion capability to Caco-2 cells, thereupon which the bacteria may reduce the accumulation of aflatoxins in the intestine via increasing aflatoxin-bacteria complex excretion.

#### **4.4 Aflatoxin degradation by enzymes**

Some specific enzymes to degrade aflatoxins have been purified from microbial systems. Using enzyme to degrade aflatoxins have some merits, such as avoiding to change flavor or impairing the nutritional value. Motomura et al. [52] investigated the ability of degrading AFB1 in cultured supernatants from 19 fungi and purified 1 enzyme with aflatoxin degradation activity from *P. ostreatus* supernatant. The enzyme showed that AFB could make the best degradation of activity at 25°C with a pH of 4.0–5.0. The novel enzyme could cleave the lactone ring of aflatoxin. Another study showed that an intracellular enzyme, named aflatoxin-detoxifizyme, exhibited detoxification activity on aflatoxin B1 and the optimum activity for the enzyme was at 35°C with a pH of 6.8 [53]. Shcherbakova et al. [54] also proved AFB1 degradation by *Phoma glomerata* PG41 strain was stable and reproducible.

#### **4.5 Cold plasma technology to remove AFB1**

In the past cold plasma is used for sterilization of sensitive materials. Lately, much attention has been paid to cold plasma as a new microbial decontamination technology in the food industry. It has the advantages of high efficiency and short treatment time, no residue, and low impact on the quality of treated food products [55, 56]. Recently the degradation of mycotoxins by cold plasma was studied.

**183**

*Decontamination of Aflatoxin B1*

12 min [60, 61].

respectively [63].

gastrointestinal tract [68].

*DOI: http://dx.doi.org/10.5772/intechopen.88774*

**5. Sorbent additives for degradation of AFB1**

effective method to reduce AFB1 toxicity in the foods.

**6. Other methods to degrade of AFB1**

and from 24.0 to 63.8% at pH 6.0.

It was reported that AFB1 could be successfully removed by 5 s of treatment with microwave-induced argon plasma [57]. Nitrogen gas plasma could efficiently bw degraded to 10% of initial concentration within a 15-min treatment [58]. Lowtemperature radio-frequency plasma degraded 88% of AFB1 within 10 min [59]. High-voltage atmospheric cold plasma (HVACP) is a novel nonthermal decontamination technology that has the potential to be used in the food industry. HVACP treatment of aflatoxin has been shown to degrade 70% of the total aflatoxin in

There is one approach to solve AFB1 contamination is the addition of sorbents

in the foods. This process is not the same as the degradation process, because it does not involve destroying or reducing the amount of AFB1 in the foods or feeds. They act as binding agents to prevent AFB1 absorbed from intestinal tract after ingestion. Chlorophyllin added to the contaminated feeds could reduce AFB1-DNA adduct by 37% in rainbow trout which led to a 77% reduction of tumor incidence [62]. Another study observed that chlorophyllin exhibited the reduction of AFB1-DNA adducts, boasting the reduction of AFB1-album adducts by 65% and urinary AFM1 by 90% in rats; chlorophyll also reduces AFB1-DNA adducts, AFB1-album adducts, and urinary AFM1 levels by 55, 51, and 92%,

Clay works similarly to chlorophyll and chlorophyllin. By addition of the clay into the animal feeds, AFM1 level in milk is reduced accordingly with the decrease of AFB1 absorption rate [64]. And no overt toxicities were observed after SD rats were fed with NovaSil clay (NS) for more than half year [65]. For human beings, NS was performed for clinical study, and the side effect were reported in 99.5% of the persons as compared to the control group. After 3 months, the level of AFB1 albumin adduct was significantly decreased in both low-dose group and high-dose group. The level of AFM1 in urine samples decreased 58% in the high-dose group in 3 months. And there was no liver and kidney function or hematological parameter change reported [66, 67]. From these studies, NS diet can be regarded as a safe and

In addition, different types of mineral clays have been tested for their capabilities to bind AF in animal feeds. These absorbents, such as activated carbon (charcoal), zeolite, and saponite-rich bentonite, reduced AFB1 absorption in the

Recently, some inexpensive, new promising methods on top of conventional methods for decontamination of food and raw materials have been developed. In the beer or wine factories, some fermentation residues were observed to have the ability of degradation of AFB. A group in Italy have shown that biosorption of mycotoxins onto grape pomace may be a reasonably low-cost decontamination method. The theoretical maximum adsorption capacities (mmol/kg dried pomace) were calculated at pH 7 and 37°C; around 1 hour of contact, that pomace could adsorb almost half of initial AFB1 concentration, but it seems the adsorption rate was kept stable within pH ranges [69]. Similarly, Bovo et al. [70] also found AFB adsorption by beer fermentation residue (BFR) ranged from 45.5 to 69.4% at pH 3.0 *Aflatoxin B1 Occurrence, Detection and Toxicological Effects*

**4.3 Yeasts and lactic acid bacteria**

Kusumaningtyas et al. found *Rhizopus oligosporus* was able to inhibit synthesis or to degrade AFB1 when cultured together with AFB1-producing fungi *A. flavus* [43].

The mechanism of degradation AFB by yeasts and lactic acid bacteria is due to their adhesion to cell wall components. However the role of yeasts and lactic acid bacteria on AFB is controversial. A few study showed there was no effect of yeasts and lactic bacteria upon aflatoxin [44]. The results showed that high levels of aflatoxins in raw maize would not be degraded during the fermentations in the processing of the west African traditional food "kenkey." Other studies reported very efficient aflatoxin reductions after fermentation. Chu et al. [45] reported that AFB1 concentration dramatically decrease during brewing process, which suggested that *S. cerevisiae* yeasts sorb mycotoxin. AFB1 was detoxified into a nontoxic new fluorescing compound corresponding to AFB2a during yogurt-making and dairy product fermentation [46, 47]. Drinking water with *S. cerevisiae* strain showed a positive protection effect on the relative weight of the liver and histopathological and biochemical parameters when giving the diets contaminated with AFB1 [48]. Lactic acid bacteria have been previously reported to possess antimycotoxigenic activities both in vitro and in vivo. The specific strains of lactic acid bacteria will bind selected dietary aflatoxin contaminants. The ability of 12 *Lactobacillus*, 5 *Bifidobacterium*, and 3 *Lactococcus* bacteria strains to bind AFB1 was investigated by Peltonen et al. [49]. Two *Lactobacillus* amylovorus strains and one *Lactobacillus rhamnosus* strain removed more than 50% AFB1 rapidly after a 72-hour incubation period. Another two lactic acid bacteria *Lactobacillus rhamnosus* strain GG (LBGG) and *L. rhamnosus* strain LC-705 (LC705) can significantly and very quickly remove approximately 80% AFB1 from culture media in both temperature- and bacteria concentration-dependent manner [50]. Kankaanpaa et al. [51] found that the binding of AFB1 to *L. rhamnosus* GG decreased its subsequent adhesion capability to Caco-2 cells, thereupon which the bacteria may reduce the accumulation of aflatox-

ins in the intestine via increasing aflatoxin-bacteria complex excretion.

Some specific enzymes to degrade aflatoxins have been purified from microbial systems. Using enzyme to degrade aflatoxins have some merits, such as avoiding to change flavor or impairing the nutritional value. Motomura et al. [52] investigated the ability of degrading AFB1 in cultured supernatants from 19 fungi and purified 1 enzyme with aflatoxin degradation activity from *P. ostreatus* supernatant. The enzyme showed that AFB could make the best degradation of activity at 25°C with a pH of 4.0–5.0. The novel enzyme could cleave the lactone ring of aflatoxin. Another study showed that an intracellular enzyme, named aflatoxin-detoxifizyme, exhibited detoxification activity on aflatoxin B1 and the optimum activity for the enzyme was at 35°C with a pH of 6.8 [53]. Shcherbakova et al. [54] also proved AFB1 degradation by *Phoma glomerata* PG41 strain was stable and reproducible.

In the past cold plasma is used for sterilization of sensitive materials. Lately, much attention has been paid to cold plasma as a new microbial decontamination technology in the food industry. It has the advantages of high efficiency and short treatment time, no residue, and low impact on the quality of treated food products [55, 56]. Recently the degradation of mycotoxins by cold plasma was studied.

**4.4 Aflatoxin degradation by enzymes**

**4.5 Cold plasma technology to remove AFB1**

**182**

It was reported that AFB1 could be successfully removed by 5 s of treatment with microwave-induced argon plasma [57]. Nitrogen gas plasma could efficiently bw degraded to 10% of initial concentration within a 15-min treatment [58]. Lowtemperature radio-frequency plasma degraded 88% of AFB1 within 10 min [59]. High-voltage atmospheric cold plasma (HVACP) is a novel nonthermal decontamination technology that has the potential to be used in the food industry. HVACP treatment of aflatoxin has been shown to degrade 70% of the total aflatoxin in 12 min [60, 61].
