**3. Chemical treatment to degradation of aflatoxins**

The use of chemical additives upon the contaminated foods has been one popular method, especially the additives themselves would be used in the foods.

#### **3.1 Ammonia decontamination treatment**

Ammonization of maize, rice, barley, peanuts, and cottonseeds to alter the toxic and carcinogenic effects of aflatoxin contamination has been intensely researched by the scientists from government agencies and universities in the world. Several studies have shown that aflatoxin B1 levels were reduced effectively and permanently by 1 hour ammonia treatment. Treatment with either NH4OH at high temperature or gaseous NH3 can effectively reduce aflatoxin B1 content sometimes reaching above 99%. But at lower temperature, for example, at 25°C, AF1B level could not be reduced very well. Their study revealed that the moisture level of the product and holding temperature were the crucial factors to have influence upon the efficacy of aflatoxin decontamination [26–29]. The degradation of AFB1 is ammonization of aflatoxin (AFD1), which has been shown to be far less mutagenic than AFB1.

#### **3.2 Hydrochloric acid (HCl) treatment**

Aly and Hathout [30] investigated the effect of hydrochloric acid on AFB1 degradation in contaminated corn gluten under different HCl concentrations. The effect of AFB1 degradation by HCl is in a temperature-, HCl concentration-, and time-dependent manner. During the wet milling process, treating with 1 mol/L HCl at 100°C resulted in degradation of AFB1 by 27.6% after 4 hours and reached to 42.5% after 8 hours. When concentration of HCl increased, the degradation of AFB1 increased, and it will completely degrade AFB in the presence of 5 mol/L HCl after 4 hour at 110°C.

#### **3.3 Lactic acid and citric acid treatment**

Previous studies have shown that some organic acids have detoxification ability in treatment of aflatoxin-contaminated foods [31]. Mendez-Albores et al. showed that citric acid and lactic acid have efficiency upon aflatoxin degradation. When the acid concentration increased, the amount of B-aflatoxins decreased, and citric acid has more notable effect upon AFB degradation. Lee et al. also found the reduction rates of AFB1 in 1.0 N citric acid and lactic acid treatment for 18 hour could reach 94.1 and 92.7%, respectively [11].

#### **3.4 Ozonation treatment**

Ozonation is another commonly used chemical control method. Ozonolysis at a concentration 6–90 mg/L is effective to degrade AFB1 in short-time treatment. As short as 15 min, all molds were inactivated, and *Aspergillus parasiticus* and *Aspergillus flavus* were isolated from dried figs, while AFB1 was degraded in

**181**

**4.2 Fungi**

*Decontamination of Aflatoxin B1*

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

**4. Biological treatment to degrade aflatoxins**

other non-biological degradation methods.

tion of AFB1 in the food and feed process.

**4.1 Soil bacteria**

time-dependent manner in dried figs [32]. Aflatoxins in the peanuts at moisture content of 5% (w/w) were sensitive to ozone and easily degraded when treated with 6.0 mg/l of ozone for half hour at room temperature. The detoxification rates of the total aflatoxins and aflatoxin B1 (AFB1) were 65.8% and 65.9%, respectively [33]. Another study also showed that 89.4% AFB1 in the peanuts was decomposed by ozone with a concentration at 50 mg/L, flow rate 5 L/min for 60 hours [34].

Using microorganisms or enzymes for biodegradation of aflatoxins is one of the well-known strategies to decrease the level of aflatoxins in the foods or feed products. The methods of biologically based interventions are being actively studied because they are efficient, specific, and environmentally friendly as compared with

Many bacteria in the soil are able to degrade aflatoxins. *Flavobacterium aurantiacum* NRRL B-184, a kind of bacteria from the soils and water, showed that it can detoxify aflatoxins in high efficiency. The study from Ciegler et al. [35] showed that *F. aurantiacum* NRRL B-184 removed aflatoxin irreversibly from contaminated milk, oil, peanut butter, peanuts, and corns and partially removed from soybeans. The aflatoxins are not only removed away by *F. aurantiacum* NRRL B-184 but also failed to form any new toxic products. The bacteria was also reported that AFM1 could be removed by it from milk [35]. During monitoring the roles of such metal ions as Cu2+, Mn2+, Zn2+, and other chemical materials on AFB1 degradation by the bacteria, they could increase AFB1 degradation by 10–15% [36–38], suggesting enzymatic system was involved in aflatoxin B1 degradation by *F. aurantiacum*. Except *F. aurantiacum*, other microorganisms, for example, *Nocardia asteroides* and *Corynebacterium rubrum*, are able to detoxify aflatoxin [5, 39]. *Mycobacterium fluoranthenivorans* sp. nov. DSM44556, as a single carbon source from soil of a former coal gas plant, could reduce AFB1 concentration to amounts of 70–80% of the initial concentration within 36–48 hours, and no AFB1 could be detected in 72 hours [40, 41], while the cell-free extracts of *M. fluoranthenivorans* sp. nov. DSM44556 degraded AFB1 more than 90% the initial amount of AFB1 at high temperature within 4 hours and fully degraded in 8 hours [41]. Teniola et al. showed that *N. corynebacterioides* DSM20 151 could degrade more than 90% of AF1B after 24 hours treated in cell-free extracts. Alberts et al. [42] examined that AFB1 was biodegraded by *Rhodococcus erythropolis* in liquid cultures. AFB1 was dramatically degraded to 32% of initial concentration by extracellular extracts from *R. erythropolis* liquid cultures. Thus *F. aurantiacum*, *M. fluoranthenivorans*, and *N. corynebacterioides* could be a potential and promising application because of their potent efficient degrada-

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.

#### *Decontamination of Aflatoxin B1 DOI: http://dx.doi.org/10.5772/intechopen.88774*

time-dependent manner in dried figs [32]. Aflatoxins in the peanuts at moisture content of 5% (w/w) were sensitive to ozone and easily degraded when treated with 6.0 mg/l of ozone for half hour at room temperature. The detoxification rates of the total aflatoxins and aflatoxin B1 (AFB1) were 65.8% and 65.9%, respectively [33]. Another study also showed that 89.4% AFB1 in the peanuts was decomposed by ozone with a concentration at 50 mg/L, flow rate 5 L/min for 60 hours [34].
