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• Introduction
• Experimental Procedure
• Results and Discussion
• Conclusion
• References

Introduction

Hydrogen peroxide (H₂O₂) is a mild antiseptic for cleaning and bleaching. It is approved by the US Food and Drug Administration (FDA) for packaging and surface sterilization in the food industry. The permissible limit is <0.5 ppm hydrogen peroxide in distilled water packaged under production conditions (assay to be performed immediately after packaging).¹

There is a need to determine residual peroxide in a rapid and sensitive manner in the fast production setting as conventional peroxide determination is mainly by titrimetric or spectrophotometric methods.

Experimental Procedure

RQflex^® 20 with Reflectoquant^® Peroxide Test Kit (0.2 to 20 mg/L)

Results and Discussion

Results determined for a blank water solution, a positive control standard with 0.5 mg/L H₂O₂ and an example sample are shown in Table 1.

If the peroxide-treated containers were fully dried before the water rinsing step, no peroxide would be detectable. This residual peroxide test can be employed to optimize the disinfection spray-dry cycles so that the residual peroxide is below the safe limit before the filling process.

Notes on the measurement:

1. For rinse solutions, the peroxide concentration measured in the sample solution is used.
2. If the measurement value exceeds the measuring range (HI is shown on the display), repeat the measurement using fresh, diluted samples until a value less than 20.0 mg/L H₂O₂ is obtained.
3. For the peroxide concentration at the full container capacity, the result of the analysis is:
   Measurement value x (rinse volume/container volume)

Conclusion

The RQflex^® 20 reflectometer along with the Reflectoquant^® peroxide test (0.2-20.0 mg/L) are suitable for the determination of residual peroxide in food packaging and containers. The RQflex^® 20 is a rugged and portable hand-held device, ideal for use in production lines. The system is sensitive to peroxide levels from 0.2 mg/L and does not require additional reagents or extensive sample preparation. This is an easy yet rapid quantitative test with a total measurement time of ~20 seconds for each sample compared to conventional titrimetric or spectrophotometric methods.