This study compared fermentation, membrane and washing as three detection methods for contaminating microbes in precast plastic containers for dairy products at different storage periods and at different degrees of contamination. Filtration and washing were more effective sampling means and could provide a better understanding of microbial contamination in the plastic containers than fermentation. However, filtration was unsuitable for high-level contamination. Therefore, the washing method is more suitable for large-scale detection in industrial practice.