Uncertainties in the risk assessment of three mycotoxins: aflatoxin, ochratoxin, and zearalenone

Abstract

The risk assessment of mycotoxins is made up of two major components: an exposure assessment and a hazard assessment. There are many uncertainties in both of these components. This paper will briefly discuss the various aspects of the risk assessment process as it applies to mycotoxins and will then focus mainly on some of the uncertainties in the hazard assessment component of several carcinogenic mycotoxins. To arrive at an estimated "safe dose" (end point of the hazard assessment), we have previously used two major approaches: the no observed effect level (NOEL) divided by a safety factor approach and a mathematical (robust linear) extrapolation to a "virtual safe dose." Both of these approaches use only points from the no observed effect region of the dose-response curve and ignore valuable data from the response region. It is proposed to use the dose at which 50% of the animals would have developed tumors (the TD50) divided by a large safety factor of 50,000 as an additional estimate of "safe dose". For many studies, the TD50 lies within the observed response region of the dose-response curve and may have more validity. It is also suggested in certain cases that some of the uncertainties regarding the NOEL can be reduced if one uses a statistically derived no effect level (NEL).

Aflatoxin M1 in UHT milk consumed in Turkey and first assessment of its bioaccessibility using an in vitro digestion model

“…day À1 for AFM 1 based on a risk level of 10 À5 . The value of estimated AFM 1 intake through milk by this exposure assessment is 25 times lower than the TDI proposed by Kuiper-Goodman (1990). This preliminary data showed that estimated exposure to AFM 1 through milk consumption does not represent a serious toxicological risk for Turkish adults.…”

Estimate of aflatoxin M1 exposure in milk and occurrence in Brazil

“…Thus, there are not TDI for AFM 1 . Alternatively, estimates of safe intake can be determined dividing the TD 50 (the daily dose rate in mg/kg bw per day to induce tumours in half test animals that would have remained tumor-free at zero dose) by an uncertainty factor of 5000, a value equivalent to a risk level of 1:100,000 (Kuiper-Goodman, 1990). This approach can, therefore, be used for both genotoxic and non-genotoxic agents, which is especially useful when there is some uncertainty regarding the mode of action (Kuiper-Goodman, 1996).…”

Ochratoxin A in Ruminants–A Review on Its Degradation by Gut Microbes and Effects on Animals

“…Several reviews on different aspects of OTA have been published including overviews on general aspects [12,13,14,15,16], on OTA as a storage mycotoxin [17], on OTA and its mode of action [18,19,20], on carcinogenic potential of OTA [21], on general risk assessment of OTA [22] or on decontamination [23,24]. …”