Mycotoxin inactivation

Hicks, J.K. et al., Aspergillus spomlation and mycotoxin production both require inactivation of the FadA G protein-dependent signaling pathway, EM BO J., 16, 4916, 1997. 

Chemical detoxification processes or decontamination will include degradation, destmction and/or inactivation of the mycotoxin. In any such process the reduction of the mycotoxin to safe levels should not result in toxic degradation products or reduce the palatability or nutritional properties of the commodities. Aflatoxin has been the subject of most studies and only a relatively small number of these offers any hope of success. There is as yet no FDA or EC fully approved method for aflatoxin detoxification in human foods. Current methods in advanced stages of approval use ammonia in the gaseous form or as an ammonium hydroxide solution at various temperatures, pressure, moisture contents and reaction time to degrade aflatoxins in various animal feedstuffs. There have been extensive studies using two processes, viz ... 

Detoxification of mycotoxins can be achieved by removal or elimination of the contaminated commodities or by the inactivation of toxins present in the commodities through various physical, chemical and biological means. For a successful detoxification procedure, the following basic criteria have been suggested [199] ... 

Inactivation of mycotoxins. When removal or elimination of mycotoxins is not possible, mycotoxins can be inactivated by (a) physical methods such as thermal inactivation, photochemical or gamma irradiation (b) chemical methods such as treatment of commodities with acids, alkalis, aldehydes, oxidizing agents, and gases like chlorine, sulfur dioxide, ozone and ammonia [201] and (c) biological methods such as fermentations or enzymatic digestions that cause the breakdown of mycotoxins [202]. 

The T-2 mycotoxins have a low molecular mass of 250-500 Da, are nonvolatile compounds produced by filamentous fiingi or molds of the genus Fusarium, and are extremely stable in the environment. Of the multiple mechanisms of actions, many are poorly understood. However, their most notable effect stems from their ability to rapidly inhibit protein and nucleic acid synthesis. Thus, they are markedly cytotoxic to rapidly dividing cells, such as in the bone marrow, G1 tract (mucosal epithelium), skin, and germ cells. This cytotoxic effect imitates the hematopoietic and lymphoid effect of radiation sickness, thus the mycotoxins are referred to as radiomimetic agents. The mycotoxins also alter ceU-membrane strucmre and function, inhibit mitochondrial respiration, and inactivate certain enzymes. Decontamination requires the use of hypochlorite solution under alkaline conditions, such as 1% sodium hypochlorite and 0.1 M NaOH with 1 h contact time (USAMRICD, 2005). 

Ozone is a strong anti-microbial agent with several potential applications in the food industry. High reactivity and spontaneous decomposition to a non-toxic product (i.e. Oxygen) make it a viable disinfectant, ensuring microbial safety of food products (Fisher et al. 2000 Kim et al. 1999 Restaino et al. 1995 Horvath et al. 1985). It is recognized as safe (GRAS). It can be used as a gas or mixed in water. It was successfully used to inactivate mycotoxins, pesticide residues. 

The trichothecene mycotoxins are nonvolatile compounds produced by molds. They are very stable and resist heat- and ultraviolet light-induced inactivation. Only after heating at 500°F for 30 minutes will the toxins inactivate. 

As a general rule, the decontamination procedure recommended for chemical warfare agents4 effectively destroys toxins. Exposure to 0.1% sodium hypochlorite solution (household bleach) for 10 minutes destroys most protein toxins. The tricho-thecene mycotoxins require more stringent measures to inactivate them, but even they can be removed from the skin (although not inactivated) simply by washing with soap and water. Soap and water, or even just water, can be very effective in removing most toxins from skin, clothing, and equipment. 

When maintained as either crystalline powders or liquid solutions, trichothecene mycotoxin compounds are stable when exposed to air, light, or both. 35 44 Moreover, these mycotoxins are not inactivated by autoclaving but require heating at 900°F for 10 minutes or 500°F for 30 minutes for complete inactivation. A 3% to 5% solution of sodium hypochlorite is an effective inactivation agent for them.44 The efficacy of this solution can be increased by the addition of small amounts of alkali. 

As soon as individuals or units suspect that they have been exposed to a mycotoxin attack, they should remove their BDUs, wash their contaminated skin with soap and water, and then rinse with water. Washing the contaminated area of the skin within 4 to 6 hours after exposure to T-2 toxin removed 80% to 98% of the toxin and prevented dermal lesions and death in experimental animals.25 Contaminated BDUs as well as wash waste from personnel decontamination should be exposed to household bleach (5% sodium hypochlorite) for 6 hours or more to inactivate any residue mycotoxin. 

The trichothecene mycotoxins are low-molecular-weight nonvolatile compounds produced by certain molds. They are not water soluble but are soluble in alcohols. They are very stable to heat and ultraviolet light but are inactivated by alkaline... 

When investigating ranoval of deoxynivalenol from solution by LAB, Franco, Garcia, Hirooka, Ono, and dos Santos (2011) reported that both viable and nonviable cells (heat inactivated by pasteurization or sterilization) led to toxin removal. However, inactivated cells bound more deoxynivalenol from solution than viable cells, with all cells inactivated by sterilization showing a significant iuCTease in binding compared to viable cells. According to the authors, this indicates that the main mechanism of detoxification was adsorption of mycotoxin by the cell components of LAB. Since the heat treatment most likely exposed cell wall components and plasma manbranes that would not be available otherwise, an increase in adsorption by those treated cells would be expected, which was confirmed by the experiment results (Franco et al., 2011). 

Ueno, Y. and Matsumoto, H. (1975). Inactivation of some thiol-enzymes by trichothecene mycotoxins for Fusarium species. Chem. Pharm. Bulletin. 23, 2439-2442. 

The fiimonisins are unique among mycotoxins because they are water-soiuUe, as well as heat-staUe and resistant to the alkali treatments used to inactivate many other common mycotoxins. 

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