Bacterial Contaminations in Commercial Raw Noodles, Boiled Noodles and Noodle Factories, and Shelf Life of Boiled Noodles

Abstract

Bacterial examinations were carried out on raw noodles, boiled noodles and swabbed samples of utensiles and equipments of noodle-factories in Osaka city, and as well as preservation tests on boiled noodles.
Of the raw or boiled noodle samples, 81.1% showed less than 10³ CFU/g, thus bacterial contamination was comparatively low. However, total coliforms and Staphylococcus were found in 22.2% and 5.6% of the boiled noodles, respectively.
Micrococcus was the dominant species of microflora in raw noodles, but the microflora of boiled noodles was composed of Micrococcus, Staphylococcus, as Acinetobacter, Moraxella and etc.
In the preservation test of boiled noodles, significant bacterial growth was not observed at 5°C even after 3-day-incubation, but at 20°C, the bacterial count reached 10⁸ CFU/g, after 1-day incubation. At 35°C the sample was completely putrefied with 10⁸∼10⁹ CFU/g.
The bacterial assay of swabbad samples indicated that the contamination was caused by cooling bathes and Micrococcus, Flavobacterium and Moraxella were the dominant microflora.
These findings indicate the importance of sanitary control in noodle factories, in particular cooling bathes, and low temperature control in the marketing process.