Detoxification Treatments for Solid Foods and Feeds: History
View Latest Version
Please note this is an old version of this entry, which may differ significantly from the current revision.
Contributor:
Alaa Abou Dib
,
Jean Claude Assaf
,
André El Khoury
,
Sami El Khatib
,
Mohamed Koubaa
,
Nicolas Louka

Mycotoxins in solid foods and feeds jeopardize the public health of humans and animals and cause food security issues. The inefficacy of most preventive measures to control the production of fungi in foods and feeds during the pre-harvest and post-harvest stages incited interest in the mitigation of these mycotoxins that can be conducted by the application of various chemical, physical, and/or biological treatments. These treatments are implemented separately or through a combination of two or more treatments simultaneously or subsequently. The reduction rates of the methods differ greatly, as do their effect on the organoleptic attributes, nutritional quality, and the environment.

  • mycotoxins
  • mitigation treatments
  • decontamination rates
  • single treatments
  • physical treatments
  • chemical treatments
  • biological treatments
  • Solid foods
  • feeds

1. Chemical Treatments

Chemical decontamination is used in many industries [26]. It can be used for the destruction of mycotoxins or their neutralization [39]. Many chemical agents are used for the decontamination of solid foods and feed, such as limewater [40], organic acids [41], ozone [42], and ammonia [43]. All these treatments are discussed below in this section (Table 1).
Table 1. Chemical treatments for the reduction of mycotoxins in solid foods and feeds.
Technique Feeds/Foods Contaminants Experimental Parameters Reduction Rate Advantages/Disadvantages References
Ozonation Powdered sun-dried herbs and spices AFs Ozone concentration = 3 ppm/time 210 min Highest level of aflatoxin reduction:
93.75% for licorice
90% for peppermint		 Advantages:
Fumigation with Ozone: 3 ppm/time: 280 min— Sanitation and reduction of microbial load;
Active against a wide range of microorganisms, viruses, Gram-negative and Gram-positive bacteria, spores, and fungi;
Instability of Ozone—transformation into O2-O3 has a Gras status;
The major biologically active constituent attributed to the medical properties of the chamomile flower was increased.
Disadvantages:
Reduction of chamomile essential oil by 57.14% and peppermint by 26.67%.		 [44]
Ozonation Parboiled Rice Mycotoxins Parboiled rice grains treated with ozone Significant reduction of mycotoxins contamination, regardless of the time and period of application and the mycotoxin evaluated Advantages:
After soaking samples in ozone for 3 and 5 h:
Higher head rice yield, luminosity and hardness, decreased cooking time, percentage of defective grains, and soluble protein.		 [45]
Ozonation Aqueous medium TrichotheceneMycotoxins
(TC)		 Saturated aqueous ozone (≈25 ppm) Degradation of TC mycotoxins to materials that were not detected by UV or MS Disadvantages:
Ozone is a toxic gas, so all preparations were conducted in a fume hood.		 [46]
    At lower levels (≈0.25 ppm) of aqueous ozone Intermediate products were observed  
    Ozonation was sensitive to pH.    
    pH 4 to 6 Maximum reduction rates  
    pH 9 No reaction  
Ozonation Wheat DON ↓ initial concentrations of DON solution treated with ↑ concentrations of ozone, and ↑ times ↑ DON degradation rates Advantages:
No significant changes in the protein content, sedimentation value, pasting properties, and water absorption;
Improvement in the flour quality. Slight ↑ in dough development time and stability time;
No decrease in the quality of wheat for end-users;
Products produced from ozone-treated wheat flour (noodles) have a longer shelf life, lower darkening rate, and microbial growth;
No harmful residues, easy to use, and no waste.
Disadvantages:
Ozone treatment in solution is faster than gaseous treatment of scabbed wheat.		 [47]
      In Solution:
Processing time = 30 s; Ozone concentration = 1 mg L−1		 Degradation rate of DON = 54.2%  
      In scabbed wheat:
Processing time = 12h; Moisture content = 17%; Ozone gas concentration = 60 mg L−1		 Degradation rate of DON = 57.3%  
      Gaseous ozone Effective against DON in scabbed wheat  
      ↑ Ozone concentration and ↑ processing time ↑ Degradation rate of DON  
Ozonation Grains AFs Ozone concentration = 47,800 ppm
The average retention time = 1.8 min.
Screw Conveyor System		 Decreased Aspergillus flavus counts in a single pass through the screw conveyor: ↓ 96%;
Reduction rate of aflatoxin: 20–30%		 Advantages:
Treatments with humidified and dry ozone: similar effects on fungi and insects;
↑ residence time: ↑ insect mortality and mold reduction.
Disadvantages:
The total electricity cost for running the equipment at maximum load was USD 3.98/h based on an electricity rate of USD 0.11/kWh;
The reduction was not sufficient enough to be of commercial value;
Electricity and equipment are needed.		 [48]
Ozonation Rice Filamentous fungi An application of 0.393 kg O3 m−3 rice Different concentrations of ozone along the silo: 10−1, 10−2, and 10−3 (mol m−3) for the portions IP, CP, and SP, respectively; Advantages:
No damage to grain quality;
No significant alteration of the quality of rice, starch modifications, lipid peroxidation, protein profile, and microstructure alterations.		 [49]
        highest concentration of ozone in the inferior part of the silo at the ozone inlet = Strong fungi reduction  
Nixtamalization Maize AF and Fumonisins Soaking in a solution of:
  • 1% slaked lime ((Ca(OH)2)
  • Or 1% traditional liquid ash
 AF: up to 90% Advantages:
  • Increased Niacin content;
  • Peak Viscosity: lime-nixtamalized maize flour < ash-nixtamalized flour < non-nixtamalized maize flour;
  • Good consumer acceptability after sensorial evaluation of products;
  • Cost-effective due to better pasting properties;
  • Wood ash nixtamalization improves safety and quality.
Disadvantages:
  • Washing and drying steps are required at 60 °C for 16 h;
  • Slight reduction in fat, sugar, protein, and dietary fiber content.
  
    Fumonisins: up to 80% [50]
       















Nixtamalization Maize AF Traditional Nixtamalization Process-TNP Not efficient enough to eliminate aflatoxins present in contaminated maize Disadvantages:
  • This process generates a large amount of wastewater;
  • Possible reversibility in an acid medium such as the stomach.
 [51]
Nixtamalization Tortilla AFB1 Alkaline pH of the maize-dough = 10.2, Resting time = 30–40 min of resting at room temperature AFB1: 100%   [52]
Nixtamalization Maize and Sorghum FBs, DON, NIV, and ZEN The use of 5 cooking ingredients—1 g of cooking ingredient/400 mL of water at 92 °C for 40 min Advantages:
Sodium hydroxide and potassium hydroxide are good alternatives to calcium hydroxide;
Sodium hydroxide could be used in the industrial nixtamalization process.
Disadvantages:
Environmental concerns about using calcium hydroxide;
The high pH of the byproducts and wastewater when using calcium hydroxide;
Calcium chloride is not effective in reducing mycotoxins.		 [53]
      Calcium chloride as a cooking ingredient The least effect on mycotoxin reduction  
Ammoniation Groundnut press cake AFs Ammoniation at (0.5–2.0%) to feed materials/moisture content: 12–16%, at 45–55 psi, and at 80–100 °C for 20–60 min Reductions in the levels of aflatoxin of between 96% and 99% Disadvantages:
Insufficient information was available to conclude on the safety and efficacy of the proposed decontamination process;
No evidence that the proposed process is sufficient to ensure irreversibility in acid medium (GIT).		 [54]
Ammoniation Wheat kernels DON Treatment with Ammonia vapor at 90 °C for 2 h Degradation of DON >75% Advantages:
In silico evaluation estimated a decrease in toxicity and biological effects.		 [37]
      With an initial level of DON up to 2000 μg/kg Treatment efficacy is not affected
Ammoniation Corn AFs The use of aqua-ammonia Effective and inexpensive Advantages:
Effective and inexpensive, and it can be applied on the farm at low cost by sealing the grain in plastic.
Disadvantages:
Corn treated with ammonia turns dark because the sugar (altrose) is caramelized and the grain temperature increases by about 10 °F at the time of treatment;
Not an FDA-approved process and treated corn cannot be legally shipped out of state;
  • Personal safety precautions must be taken as ammonia reacts with copper, and a motor in the air stream could cause an explosion;
  • Corn treated with aqua ammonia requires drying for storage after treatment.
 [55]
         















Ammoniation Maize AFs The effect of ammonia More destructive to aflatoxins G1 and G2 compared with aflatoxin B1 and B2   [56]
      Highest detoxification rate Aflatoxins G1 (95%)
Aflatoxin G2 (93%)
      Lowest degradation rate Aflatoxin B1 (85%)
Aflatoxin B2 (83%)
Acid Selected Nuts AFs Moisture Levels:
walnut (10 ± 3 and 16 ± 3%); pistachio (10 ± 3%); peanuts (10 ± 3%)
Citric, Lactic and propionic acid at 9%
Time: 15 min		 Reduction rate of aflatoxins: citric acid (99%); lactic acid (99.9%); propionic acid (96.07%) Advantages:
Food-grade organic acids do not affect the nuts’ quality.		 [57]
      Citric acid Considerable reduction of the 4 aflatoxins; No formation of hazardous residues  
      Lactic acid Significant reduction of AFB1 and Total Afs; Increase in AFB2 and AFG2; Lactic acid converts AFB1 into AFB2 (less toxic)  
      Propionic acid More efficient to reduce AFB1  
Acid Feeds/Foods DON 5% solutions of lactic acid and citric acid Reduction of the concentration of common trichothecene mycotoxins, especially DON and its derivate 15Ac-DON   [58]
      5% solutions of lactic acid and citric acid No or only small effects on zearalenone, fumonisins, and culmorin  
      Lactic acid treatment Decreased concentration of nivalenol    
Acid - AFB1 1 M citric acid—at Room temperature—Time: 96 h conversion of AFB1 to AFB2a >97% Advantages:
Organic acids have few detrimental effects;
Under these conditions, > 71% of AFB1 was hydrated to AFB2a and did not show any reversion to the parent compound after being transferred to a neutral solution;
Conversion of AFB1 to AFB2a in a gastric environment can be enhanced by the addition of citric acid.
Disadvantages:
Discoloration of various types of meats including beef, pork, and fish along with minor alterations in odor and taste.		 [59]
   



0.1 and 1 M citric acid—at boiling temperature—Time: 20 min







Conversion of AFB1 to AFB2a > 98%



 

2. Physical Treatments

Many traditional methods, such as cleaning and sorting, are used. These methods are capable of physical separation by removing the contaminated portions from the crops and preventing the transfer of the pathogens to the non-contaminated portions. These are not able to neutralize or degrade the mycotoxins already produced in the crops; they only isolate the contaminated portions [28,66,67]. Several industrial processes require the use of conventional cooking at temperatures below 100 °C. Most mycotoxins are heat stable, and it is not possible to mitigate them by these conventional heat treatment processes [68].
The physical detoxification methods explained in this section (Table 2) include thermal treatments or invasive methods such as extrusion [68], and non-thermal treatments or non-invasive methods such as photocatalysis [69], cold plasma [70,71], electrolyzed oxidizing water [72], and irradiation [73,74]. These technologies are beneficial since they are safely used for many food matrices without causing negative effects on the nutritional and organoleptic quality of treated food. The limited scalability at the industrial level may be considered a disadvantage of many physical treatments [75].
Table 2. Physical treatments for the reduction of mycotoxins in solid foods and feeds.
Technique Feeds/Foods Contaminants Experimental Parameters Reduction Rate Advantages/Disadvantages References
Photocatalysis Wheat DON In solution: DON concentration = 10 μg/mL, time = 60 min, simulated sunlight: using NaYF4:Yb,Tm@TiO2 (6 mg/mL), pH = 8.0 Rate of DON degradation ≈ 100% Disadvantages:
Decreased efficiency caused by shielding effect.		 [69]
      3 photocatalytic degradation products were identified C15H20O8, C15H20O7, and C15H20O5  
      In wheat:1 mL of 50 μg/mL DON standard solution + 5 g wheat-soaked and naturally dried. Degradation rate at 120 min = 69.8%  
      Toxic grains + UCNPs aqueous solution/ratio 1:1  
      After 1 h of adsorption equilibrium, the wheat samples were illuminated by Xe lamp (200–2500 nm) for 5, 15, 30, 60, 90, and 120 min, respectively  
Photocatalysis Wheat DON In wheat: The dosage of photocatalyst UCNP@TiO2 was 8 mg mL−1 Time: 90 minRatio of wheat to liquid: 1:2 Degradation rate at 90 min = 72.8% Advantages:
  • Little effect on the starch content, protein content, amino acid content, and fatty acid value of wheat.
Disadvantages:
  • The gluten content and pasting properties of wheat flour decreased significantly;
  • The whiteness of wheat flour decreased, and the yellowness increased;
  • The surfaces of starch granules were damaged to varying degrees with the prolongation of illumination time;
  • The fatty acid value and wet gluten content and pasting properties of wheat decreased significantly during photocatalysis;
  • The composite is easily removed by washing = low exposure dose.
 [76]
Plasma Corn AFB1 CAP is generated by a Surface Barrier Discharge (SBD) system operating in ambient air, yielding RONS by a generation of non-equilibrium atmospheric pressure plasma in ambient air Reduction rate of AFB1 after 60 s: 96% Advantages:
  • It requires less time than UV irradiation;
  • Surface Barrier Discharge (SBD) plasma system was employed due to its practicability and scalability in the agri-food field.
 [77]
      Initial concentration of AFB1 = 35 μg/ml 100% AFB1 decontamination in less than 120 s of treatment
Plasma Oat Flour T-2
and
HT-2		 Low-pressure dielectric barrier discharge (DBD) plasma/different gases/time: 10–30 min   Disadvantages:
  • Time-dependent effect of T-2 toxin treatment for the 4 gases;
  • This treatment has similar thermal processing on mycotoxins such as cooking, roasting, and extrusion; Possible explanation-conversion of T-2 into HT-2 toxin and complex degradation pattern.
 [78]
      Exposure to nitrogen for 30 min The maximal reduction of T-2 toxin degradation (43.25%)
      Exposure to nitrogen for 30 min The maximal reduction of HT-2 toxin degradation (29.23%)
      Mean degradation rate of T-2 toxins in all experiments 25.01%
      Mean degradation rate of HT-2 toxins in all experiments 20.98%
      Oxygen and air as working gas No significant reduction of T-2 and HT-2
Plasma Maize AFB1 and FB1 Pulsed dielectric barrier discharge (DBD) jet:   Advantages:
  • Minimal impact on the organoleptic characteristics (e.g., firmness, color, pH);
  • Minimal impact on the nutritional value of the treated foods (ascorbic acid, flavonoids);
  • The low penetration depth of CAPP treatment is thought to limit degradation to a thin surface layer and so protects the majority of nutrients.
Disadvantages:
  • Its influence was shown to be dependent on the produce exposed, with losses in antioxidants or lipids reported;
  • An enclosed environment is necessary to improve detoxification rates.
 [79]
      Spiked maize grains are placed at 12 mm beneath plasma jet—Time = 10 min  
      Concentration of AFB1 = 1.25 ng/g Degradation rate after 10 min of plasma exposure = 65%
      Concentration of FB1= 259 ng/g Degradation rate after 10 min of plasma exposure = 64%
Plasma Roasted coffee OTA Treatment with cold plasma: Imput power = 30 W/output voltage = 850 V/Helium flow = 1.5 L/min for 30 min OTA reduction rate = 50%   [80]
      Using the brine shrimp (Artemia salina) lethality assay Untreated roasted coffee = Toxic Treated roasted coffee = Slightly Toxic
Pulsed Light Red pepper powder AFB1, Total AF, OTA The highest fluence applied (9.1 J/cm2, 61 pulses, 20 s) 2.7, 3.1, and 4.1 log CFU/g reduction of yeasts, molds, and total plate counts (TPC), where initial microbial loads were 4.6, 5.5, and 6.5 log CFU/g, respectively
  • Advantages:
  • The significant and apparent increase in total phenols.
  • Disadvantages:
  • Total color difference = slight difference;
  • Proportional increase in temperature of the samples, max 59.8 °C.
 [81]
      The highest fluence applied (9.1 J/cm2, 61 pulses, 20 s) A maximum reduction of 67.2, 50.9, and 36.9% of (AFB1), (AF), and (OTA) was detected, respectively    
Pulsed Light Solid medium AFB1 and AFB2 PL at different initial concentrations of AFB1 (229.9, 30.7 and 17.8 μg/kg) and AFB2 (248.2, 32.2 and 19.5 μg/kg) and irradiation intensities (2.86, 1.60 and 0.93 W/cm2) of PL The degradation of AFB1 and AFB2 followed the second-order reaction kinetic model well (R2 > 0.97); The degradation rate was proportional to the intensities of PL irradiation and the initial concentrations of aflatoxins   [82]
Pulsed Light Rice AFB1 and AFB2 PL treatment of 0.52 J/cm2/pulse for 80 s to rough rice AFB1 reduction rate = 75% AFB2 reduction rate = 39.2% Advantages:
  • Safer working environment for those involved in post-harvest handling and milling operations.
 [83]
PL treatment of 0.52 J/cm2/pulse for 15 s to rice bran AFB1 reduction rate = 90.3%AFB2 reduction rate = 86.7%  
UV-C Irradiation Brown, black, and red rice (Moisture content = 13%) Aflatoxin (B1,B2, G1, and G2), DON, OTA, and ZEN In black and red rice–the UV-C irradiation treatment (dosage of 2.06 kJ/cm2) for 1 h Effective in fungal decontamination, photo-degradation of mycotoxins Advantages:
(dosage of 2.06 kJ/cm2) for 1 h:
◦
Release of bound phenolics in black and red rice grains;
◦
No changes in cooking and color properties.
Disadvantages:
(dosage of 6.18 kJ/cm2) for 3 h:
◦
Reduced the total content of phenolic compounds in black and red rice;
◦
Browning grains.
 [73]
  In black and red rice—the UV-C irradiation treatment (dosage of 6.18 kJ/cm2) for 3 h Increased the efficiency of fungal decontamination and reduced mycotoxins
  In brown rice, the treatment conditions need to be optimized since only the dosage of 6.18 kJ/cm2 Reduction of fungal contamination
UV-C Irradiation Maize and peanut AFB1 After ten days of incubation and irradiation treatment delivering a dose of 8370 mJ/cm2 The highest reduction of A. flavus count was 4.4 log CFU/g in maize and 3.1 log CFU/g in peanut Advantages:
  • Only minimal changes in the evaluated sensory and physical characteristics (color and texture).
 [84]
Depending on the treatment AFB1 reduction level:In maize ranged from 17 to 43% In peanut ranged from 14 to 51%
UV-C Irradiation Peanut AFB1 The darkening of the UV indicator (AgCl) Linearly proportional to the UV dosage from 0 to 120 mJ/cm2 delivered on peanuts Advantages:
  • Reducing time-consuming tasks, such as replacing manual color measurement with automatic imaging processing technology, should also be considered.
Disadvantages:
  • For scaling up the process, more parameters, such as the dimensions of peanuts, or the friction between peanuts and the chamber, should be considered;
  • The increase was not significant and the skins remaining on hollows of peanuts could protect AFB1 from being fully exposed to UV;
  • The AFB1 spiking process could also contribute to the result.
 [85]
      Rotation at 11 rpm in the cylindrical chamber Significant improvement in UV uniformity
      UV irradiation: 2.3 mW/cm2 UV-C for 2 h with rotation at 11 rpm Reduction percentage by 23.4% (from 14.3 ± 3.4% to 17.7 ± 4.5%)
      UV irradiation: 2.3 mW/cm2 UV-C for 2 h with rotation at 11 rpm Increased AFB1 degradation rate from 60.8 ± 15.3 pmol g−1h−1 to 75.0 ± 10.9 pmol g−1h−1
Gamma Irradiation Maize AF
and
OTA		 Gamma irradiation dose of 6.0 kGy Completely inhibited the growth of the two molds   [86]
    Gamma irradiation dose of 4.5 kGy Reduced the production of their mycotoxins  
    Gamma irradiation dose of 20 kGy Maximum reduction rate is as follows:
  • AFB1: 40.1%
  • AFB2: 33.3%
  • OTA: 61.1%
  
Gamma Irradiation Wheat flourgrape juiceandwine OTA In wheat flour, a radiation dose of 30.5 kGy OTA reduction rate = 24% Advantages:
  • OTA was easily degraded by gamma irradiation when dissolved in water.
Disadvantages:
  • OTA is very sensitive to irradiation in water solutions but resistant in its dry form and in food matrices;
  • Dry OTA was extremely resistant to gamma radiation.
 [87]
In grape juice, a radiation dose of 30.5 kGy OTA reduction rate = 12%  
In wine, a radiation dose of 30.5 kGy OTA reduction rate = 23%  
Gamma Irradiation Sorghum OTA and AFB1 Gamma irradiation dose of 3 kGy Sufficient to eliminate 90% of the natural fungal load of sorghum   [88]
    At a radiation dose of 10 kGy The maximum reduction rate of AFB1 = 59%  
    At a radiation dose of 10 kGy The maximum reduction rate of OTA = 32%  
Extrusion Whole grain triticale flour DON, 3- and 15-AcDON, HT-2, TEN, AME Optimal parameters of co-rotating twin-screw extruder for lowering the concentration of each investigated mycotoxins in naturally contaminated flour were: SS = 650 rpm, FR = 30 kg/h, MC = 20 g/100 g Reduction rate of mycotoxins: DON: 9.5%; 3-AcDON: 27.8%; 15-AcDON: 28.4%; HT-2: 60.5%; TEN: 12.3%; AME: 85.7%   [89]
Extrusion Cornmeal AF: B1, B2, G1, G2 Extrusion in the absence of high-amylose cornstarch A reduction in aflatoxins level: (B1: 83.7%, B2: 80.5%, G1: 74.7%, and G2: 87.1%) Disadvantages:
  • The bioaccessibility indicates that:
    ◦
    Part of aflatoxins reduction observed after the extrusion may be caused by their interactions with food matrix macromolecules;
    ◦
    Once the digestion is completed, part of these toxins becomes available for absorption in the small intestine.
 [90]
     




Extrusion in the presence of high-amylose cornstarch










Higher aflatoxins reductions were observed: (B1-89.9%, B2-88.6%, G1-75.0%, and G2-89.9%)





Electrolyzed Water Wheat grains DON For AcidEW Advantages:
  • Both pH 5.5 AcidEW and pH 9.5 AlkEW did not change the basic properties of wheat, including whiteness, moisture content, crude protein content, and wet gluten content;
  • No remarkable change in isolated starch morphology;
  • AcidEW can improve the farinograph property of wheat flours with higher stability time and FQN and a lower degree of softening;
  • AcidEW is a promising way for large-scale wheat milling operations to eliminate DON and mycological contaminations in wheat grains.
 [91]
pH 5.5 Optimal pH for DON elimination
pH 2.5 Optimal pH for fungal reduction
For AlkEW
pH 9.5 Optimal pH for DON elimination







pH from 8.5 to 12.5






Strong elimination activity on fungi
Electron Beam Red pepper powder OTA Treatment at 6 kGy
  • Reduction of yeast count by 3 log CFU/g
  • Reduction of mold count by 4.4 log CFU/g
 Advantages:
  • Retention of more than 85% of total phenols, carotenoids, and antioxidants activity;
  • No detrimental effect on the physicochemical quantities of the red pepper powder.
Disadvantages:
  • Slight color differences.
 [92]
Treatment at 10 kGy for 23 s
  • Reduction of total plate counts by 4.5 log CFU/g
  
Treatment at 30 kGy
  • Reduction rate of OTA: 25%
  
Milling Maize Mycotoxins Grain cleaning
  • Reduction of fungal metabolites by 1.2–2 times
 Advantages:
  • Flaking grits is the healthier milling product of maize with the lowest mycotoxins content.
Disadvantages:
  • Highest mycotoxins content in animal feed products threatening animal health;
  • Redistribution of mycotoxins in maize fractions after milling;
  • Most mycotoxins are concentrated in the germ.
 [93]









Milling Maize B-series fumonisins (FBs) Grain cleaning
  • Reduction rates of FBs: 42%
 Advantages:
  • Higher reduction rates of FBs are achieved by tempering degermination;
  • The separation of horny endosperm from the fine fractions is better in the tempering process;
  • Higher reduction rates are achieved in the highest-sized flaking grits.
Disadvantages:
  • The germ and animal feed flours contain a higher amount of FBs than other milling products.
 [94]
Dry-degermination process of uncleaned kernels Reduction rates:
  • Maize flour: 50%
  • Break meal: 83%
  • Pearl meal: 87%
  
Tempering degermination Process of uncleaned kernels Reduction rates:
  • Small grits: 78%
  • Medium grits: 88%
  • Flaking grits: 94%
 

3. Biological Treatments

Biocontrol showed high efficiency in the prevention of AFs formation in the pre-harvest stage when non-aflatoxigenic biological control strains are inoculated in the fields and competed with aflatoxinenic strains of Aspergillus for nutrients and place and causing their exclusion [110,111]. The studies discussed in this section aimed to mitigate the already formed mycotoxins in feeds and foods by biological treatments and not to prevent their formation in crops (Table 3).
Most studies about the mitigation of mycotoxins by biological means focused on the treatment of liquid food or milk [32,33,112], assessing the effect of yeast, bacteria, or their enzymes on the mycotoxins in buffers or solutions [30,113,114]. Biological detoxification could be the result of binding the targets by adsorption mechanisms or by degradation. This detoxification of mycotoxins can be conducted using microorganisms (bacteria, biofilm, or yeast) or their metabolites and enzymes [115]. In this section, we screen various studies using biological control strategies to mitigate the mycotoxins in solid food and feeds (Table 3).
ZEN-detoxifying bacillus strains were used to detoxify highly contaminated maize with an initial concentration of 5 mg kg−1 of ZEN. The degradation of ZEN is related directly to the esterase activity, which has been found in all tested strains, with the maximum activity in B1 and B2 strains. The highest ZEN degradation rate was attained in B2 strains, reaching 56%. B2 strains showed their efficiency in the detoxification of other mycotoxins with different rates—AFB1: 3.8%, DON: 25%, FB1: 39.5%, T2 toxin: 9.5%. The presence of ZEN enhanced the fermentation process of the contaminated maize compared to the non-contaminated grains [116].
CotA laccase is found in the endospore coat of Bacillus. It protects spores from UV light and hydrogen peroxide and has an oxidizing capacity. CotA laccase was immobilized onto chitosan microspheres and used to degrade ZEN in artificially contaminated cornmeal samples. The free CotA laccase form achieved a degradation rate of 70%, while the immobilized form was faster and more effective, achieving a higher degradation rate reaching 90%. The most important advantage is the reuse of the immobilized enzyme. Guo et al., showed that the degradation rate decreased to 54% following multiple uses of the immobilized CotA laccase in the third cycle, reaching only 21% in the fifth one [117]. Lactic acid bacteria (LAB) were used to mitigate mycotoxins in wheat-based products. The Pediococcus acidilactici LUHS29 strain achieved the highest reduction rates of mycotoxins when used alone in sourdough fermentation for 48 h. It removed 15-AcDON, AOH, D3G, toxins H-2 and HT-2, completely removed ENNB1, and reduced the DON by 44–69%. The combined fermentation using this LAB with Lactobacillus Plantarum LUHS135 strain showed great efficiency and increased the reduction rate of DON to 79–100% [118]. In a study conducted by Alberts et al., enzymatic detoxification was examined using Fumonisin Esterase FumD to degrade FB in maize. This enzyme can hydrolyze and remove the tricarballylic acid groups when added to maize during the conditioning step (for 250 min) during the dry milling process. The use of 40 U/kg of FumD in maize resulted in a 99% degradation of FBT in total hominy feed but did not accomplish any degradation of FBT in super maize meal [119].
The fungal growth and/or the mycotoxin production was controlled in bread using specific yeast strains and achieving reduction rates varying between 16.4 and 33.4% for DON, 18.5 and 36.2% for NIV, and 14.3 and 35.4% for ZEA [120]. The heat treatment of peanut samples at 100 °C for 15 min before solid-state fermentation by Zygosaccharomyces rouxii showed great efficiency in the mitigation of AFB1, and the reduction rate reached 97.52% [121].
Treatment Feeds/Foods Contaminants Experimental Parameters Reduction Rates Advantages References
Bacteria: ZEN-detoxifying Bacillus (ZDB) strains Maize ZEN The highest level of ZEN degradation B2 strain-reduction rate = 56%
  • Esterase activity is demonstrated in all strains;
  • The stronger esterase activity: B1 and B2 strains;
 [116]
    B2 strain detoxifies other mycotoxins Reduction rates:
AFB1: 3.8%;
DON: 25%;
FB1: 39.5%;
T2 toxin: 9.5%
  • Fermentation of ZEN-contaminated maize by B2 strain compared to ZEN-free maize: Better fermentation characteristics: (lactic acid > 110 mmol·L−1; acetic acid < 20 mmol·L−1; pH < 4.5).
Bacteria: Bacillus licheniformis
spore CotA laccaseapplication of immobilized laccase in contaminated corn meal		 Corn meal ZEN Treatment with immobilized CotA laccase onto chitosan microspheres for 12-h Degradation rate: 90%
  • Immobilized CotA laccase is much faster and more effective than free CotA laccase in degrading ZEN;
  • Immobilization has higher thermal stability over free CotA laccase, maintaining about 87% of its initial activity after heat treatment at 80 °C for 30 min;
  • Reusability: Immobilized CotA laccase could be recovered from corn meal solution and repeatedly used.
 [117]
    Treatment with free CotA laccase for 12-h Degradation rate: 70%
    Reuse of immobilized enzymes for 5 cycles Decreased degradation rate on each after each cycle:
Cycle 1: 90%;
Cycle 2: 77%;
Cycle 3: 54%;
Cycle 4: 30%;
Cycle 5: 21%
Bacteria—Fermentation: Lactic acid bacteria Wheat-based products DON 15
-AcDON
AOH
D3G,
toxins H-2 and HT-2:
Enniatin
ENNB1		 Pediococcus acidilactici LUHS29 strain The strongest mycotoxins decontamination effect
  • Pediococcus acidilactici LUHS29 strain has the strongest mycotoxins decontamination effect;
  • Combined fermentation showed more efficiency and complete elimination of DON.
 [118]
  Prolonged fermentation at 35 °C for 48 h with Pediococcus acidilactici LUHS29 strain DON: 44–69%
15-AcDON, AOH, D3G, toxins H-2 and HT-2: Removal
Enniatin: 5–70%
ENNB1: complete removal
  Combined fermentation (Lactic acid bacteria 7 (JCM 1149) and Pediococcus acidilactici LUHS29 (DSM 20284)) Complete elimination or effective reduction of DON: 79–100%
Enzyme Maize FB FB degradation during dry milling of maize  
  • Highest enzyme concentration: 32 U/100 g maize: Complete conversion into HFB1;
  • Cost-effectiveness of upscaling the FumD FB dry milling method to an industrial level requiring up to 40,000 U FumD/ton maize, will depend on the safety benefits of consuming the milling products as well as the commercial value of the total hominy feed lacking FBT.
 [119]
Fumonisin esterase FumD     Enzyme concentration: 40 U/kg Reduction rates FBT:
  • 99% in total hominy feed;
  • 48% in semolina;
  • 7% in special maize meal
  • No reduction in super maize meal.
Yeast Wheat grains and bread Fusarium
Mycotoxins:
DON, NIV
ZEN		 Bread prepared by baking with the addition of an inoculum of the test yeast Reduction rates:
DON: 16.4% to 33.4%;
NIV:18.5% to 36.2%;
ZEA: 14.3% to 35.4%
  • The biocontrol yeasts strains may arrest fungal growth, reduce mycotoxin production, or both.
 [120]
Yeast Peanut meal AFB1 Peanut samples are heated at 40, 60, 80, 100, or 110 °C for 10 min   [121]
      The residual rates after heat treatment at the following temperature for 10 min: (T:% of residual AFB1 80 °C: 61.08%; 100 °C: 63.46%; 110 °C: 49.63%  
      The residual rates after fermentation by Z. rouxii: (Temperature: % of residual AFB1) (40 °C:32.73%)-(60 °C:20.85%)-(80 °C:16.18%)-(100 °C:5.13%)-(110 °C:5.10%)
      100 °C The optimal temperature achieved the highest reduction rate
      Peanut samples are heated at 100 °C for 5, 10, 15, or 20 min
      The residual rates after heating at 100 °C for different times: (time: % of residual AFB1) (5 min: 21.06%)-(10 min: 5.13%)-(15 min: 2.48%)-(20 min: 2.44%)
      15 min The optimal time
      Optimal treatment (100 °C -15 min): Residual % of AFB1: 2.48%
 

This entry is adapted from the peer-reviewed paper 10.3390/foods11203304

© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license; additional terms may apply. By using this site, you agree to the Terms and Conditions and Privacy Policy.
This entry is offline, you can click here to edit this entry!
Video Production Service
Feedback