Dry pasta and noodles are extruded and dried below pasteurization temperatures, therefore pathogens may survive in the final products.
Salmonella from egg ingredients have been especially troublesome. Although levels of salmonella are reduced during processing, significant numbers survive if the original contamination is high. In Korean, Bacillus cereus was found to be the main spoilage bacteria in wet noodles.
For fresh raw and wet noodles, the moisture content or water activity level is very high and if they are not thermally processed; the microorganisms can grow very fast at proper temperature if enough oxygen is present inside the package.
Vacuuming eliminates most of the oxygen from the package and slows down the growth of microorganisms, thus extending the shelf life of the fresh noodles.
Several methods have proved to be successful in eliminating and preventing microbial contamination. These methods include irradiation, chemical fumigation, sterilizing with ethylene oxide and heat treatment.
Mixing noodles with very hot (90-100 °C) soup decreased the number of bacteria by 1/1000 as compared to that mixed with warm (60-70 °C) soup.
Bacterial contamination in noodles
