Case Study:Identification of Microbial Distribution and Contamination Source by PDCA Cycle at a Boiled Noodles Factory

• Published in: Food Hygiene and Safety Science (Shokuhin Eiseigaku Zasshi) Vol. 62; no. 3; pp. 79 - 84
• Main Authors: Ohyagi, Noboru, Morita, Takayuki, Sugita-Konishi, Yoshiko
• Format: Journal Article
• Language: Japanese
• Published: Tokyo Japanese Society for Food Hygiene and Safety 25.06.2021; Japan Science and Technology Agency
• Subjects: airborne environmental bacteria; Bacteria; Biological contamination; boiled noodle; Contamination; Cooling; Cooling water; HACCP; Hygiene; Manufacturing industry; Microbial contamination; Microorganisms; Moisture content; Noodles; PDCA cycle; Perishable foods; Rinsing; rinsing and cooling process; Sterilization; Water activity; Water content; Water flow; Water pollution; Water tanks
• ISSN: 0015-6426; 1882-1006
• DOI: 10.3358/shokueishi.62.79

Boiled noodles are considered to be one of the most perishable foods due to their high moisture content and high water activity. Thus, the hygiene control measures based on HACCP manuals has been recommended in the noodle manufacturing industry. However, there were several cases in which post-packaged products manufactured at the Boiled noodles factory of small-to-medium size company detected a viable cell count higher than their voluntary standards. To identify the source of microbial contamination, an investigation based on the Plan-Do-Check-Act (PDCA) cycle was conducted. The results showed that the bacteria causing the contamination were environmental bacteria. Secondary contamination occurred during the cooling process after sterilization. Airborne environmental bacteria and oxygen may have been introduced into the rinsing and cooling water tank by the strong water flow during the rinsing and cooling process, inducing growth of microorganisms in the cooling water and contaminating the final product. This is a new finding, as such occurrence was not listed in the HACCP manual and should be contributed to plan HACCP system.