Evaluation of Spindle system for effective detachment of microorganisms in food

Abstract

This study was undertaken to compare the effect of the improved spindle systems and stomacher for detaching microorganisms from various food samples. The spindle is an apparatus for detaching microorganisms from food surfaces which was developed in my laboratory. When processed with the spindle, food samples were barely disrupted, original shape was maintained, and the diluent was clear, facilitating further detection analysis more easily than with stomacher treatment. The portable spindle is weight-reduced device from the first generation spindle and 4-section spindle consists of 4 sample bag containers (A, B, C, and D) to economize time and effort by simultaneously processing 4 samples. The aerobic plate counts (APC) of food samples were measured following spindle and stomacher treatment. Correlations between the two methods for the spindle and stomacher were very high (R2 > 0.97). One-tenth ml of foodborne pathogens suspensions were inoculated onto surfaces of food samples and ratios of spindle-to-stomacher enumerations were close to 1 between the spindle and stomacher. One of the greatest features of the spindle is that it can treat large-size samples which exceed 200 g. Uncut whole apples, carrots, green peppers, potatoes, and tomatoes were processed by the spindle and by hand massaging by 2 min. Large-size samples were also assayed for APC and recovery of the 3 foodborne pathogens, and the difference between each section of the spindle and hand massaging was not significant (P > 0.05). The suspension generated by the spindle showed lower turbidity and total protein concentration. Also, significantly different threshold cycles were observed in Real-time PCR analysis using suspensions generated by both methods. This study demonstrated that the spindle apparatus can be an alternative device for detaching microorganisms from various types of samples, yielding a higher quality of suspensions which may be better suited for further molecular microbiological analysis and for field application.