October 27, 2006
During validation of the method, Determination of Furan in Foods, ruggedness testing was conducted in the form of headspace (HS) oven temperature and thermal equilibration studies. These studies were conducted on foods containing relatively high levels of incurred furan (52 to 118 ng/g) and showed that comparable results were obtained between test portions equilibrated for 30 minutes in a 60 and 80°C HS oven (Nyman, P.J., Morehouse, K.M., McNeal, T.P., Perfetti, G.A., & Diachenko, G.W. (2006) J. AOAC International, 89, No. 5, in press.).
In 2006, additional ruggedness testing was performed to evaluate the effects of temperature and time on some samples containing relatively low levels of incurred furan (1 to 6 ng/g), i.e., peanut butter, infant formula, and potato chips. For the oven temperature studies, replicate test portions of these samples were equilibrated for 30 minutes in an HS oven at 35, 60, 80, and 105°C. For the thermal equilibration studies, replicates of the same samples were equilibrated for 15, 30, 45, and 60 minutes in a 60°C HS oven.
The oven temperature studies showed that from 35 to 60°C, comparable results were obtained for the three matrices. Between 60 and 80°C, furan increased by 0.5 ng/g in infant formula and peanut butter and 3 ng/g in potato chips. Between 80 and 105°C, furan formation increased dramatically in all the products, with furan levels in potato chips increasing by as much as 30 ng/g.
The thermal equilibration studies showed that longer equilibration times at 60°C did not affect the amount of furan found in peanut butter and infant formula. For potato chips, the amount of furan increased with thermal equilibration times greater than 30 minutes. This effect may be the result of the high concentration of polyunsaturated fatty acids in potato chips. The unsaturated double bonds may provide more potential for furan formation through auto-oxidation and cleavage, as reported by Becalski and Seaman with Health Canada (Becalski, A. & Seaman, S. (2005) J. AOAC International, 88, No. 1, 102-106).
In summary, recently completed method ruggedness testing showed that low level furan formation can occur in a few relatively high fat foods when test portions are equilibrated in an 80°C oven for 30 minutes. Even though the amounts of furan formed were small (less than or equal to 3 ng/g), the method oven temperature has been reduced to 60°C to avoid the potential for furan formation during analysis. These investigations are ongoing, and future research will reevaluate potential differences between the amount of furan found in other foods at 60 and 80°C. The resulting data will be published when available.