The detection of food soils on stainless steel using energy dispersive X-ray and Fourier transform infrared spectroscopy

Abstract

Organic soiling is a major issue in the food processing industries, causing a range of biofouling and microbiological problems. Energy dispersive X-ray (EDX) and Fourier transform infra red spectroscopy (FT-IR) were used to quantify and determine the biochemical groups of food soils on stainless steel surfaces. EDX quantified organic material on surfaces where oily based residues predominated, but was limited in its usefulness since other food soils were difficult to detect. FT-IR provided spectral ‘fingerprints’ for each of the soils tested. Key soiling components were associated with specific peaks, viz. oils at 3025 cm⁻¹–3011 cm⁻¹, proteins at 1698 cm⁻¹–1636 cm⁻¹ and carbohydrates at 1658 cm⁻¹–1596 cm⁻¹, 783 cm⁻¹–742 cm⁻¹. High concentrations of some soils (10%) were needed for detection by both EDX and FT-IR. The two techniques may be of use for quantifying and identifying specific recalcitrant soils on surfaces to improve cleaning and hygiene regimes.

Keywords:

• FT-IR
• EDX
• conditioning film
• food
• biofouling
• detection

Acknowledgements

The authors would like thank Dr Christopher Liauw (School of Engineering, Manchester Metropolitan University) for his help with the FT-IR work. The authors would like to thank partners of Work Package 11 (Hygienic Processing Systems) for their advice and supply of their methodologies for preparation of complex soils. The research performed has been part of the project FOOD-CT-2005-007081 (PathogenCombat) supported by the European Commission through the Sixth Framework Programme for Research and Development.