Quality and safety aspects of deepfryer oils in takeaway food outlets

Takeaway food is a significant contributor to dietary fat intake in Australia. The deepfryer is an important appliance in Australian takeaway food outlets. If deepfryer oils are not managed appropriately, undesirable breakdown products accumulate. When 23 used oil samples and paired unused control oil samples from takeaway food outlets in north-eastern Australia were analysed for fatty acid profile and indicators of deterioration, oil identity and condition were found to differ greatly. Trans-fatty acid content was generally low, although one unused oil sample contained 43.8% (w/w). Two oil samples had polar compound contents above 25%, the highest being 28.7%. Peroxide values, and acid values, both singularly and in combination, correlated poorly with polar compound levels. These low correlation levels seemed unrelated to antioxidant levels in unused oil samples. Concentrations of BHA and TBHQ in unused oil samples varied from nil to 180 mg/kg (legal limit 200 mg/kg). Improved deepfryer oil management in takeaway food outlets presents many opportunities to enhance the quality and safety of takeaway food.