DOX system (DOX-60F/DOX-30F) rapidly evaluates the total number of microorganisms, coliforms and Escherichia coli

#25 Infection and Food Poisoning


Professor Emeritus at Hokkaido University

Advisor at Japan Food Research Laboratories

Biography of Dr. Isshiki



Diseases passed from one person to another are collectively called infections.

Infections, which were called “epidemics” due to its predisposition, spread in a short time to sicken and sometimes even kill many people without proper countermeasures.  Especially infectious diseases with a high mortality rate need strict measures.  Patients can be isolated as needed, but excessive isolations might lead to human rights violations.  Therefore, Act on Prevention of Infectious Diseases and Medical Care for Patients Suffering Infectious Diseases (Infectious Disease Law in short) specifies proper prevention and countermeasures against infections.


1) Spread of infections

How are infections transmitted and extended?  Let us see a case of Norovirus outbreak (Table 1).




Existence of Norovirus as a pathogenic microorganism starts the process.  This virus grows in the intestine of a carrier and then passes on to other people.  Once it develops, vomiting and/or diarrhea will occur and Norovirus will be carried out of the body.  Even carriers without symptoms (people in this group are called healthy carriers) pass Norovirus out of their bodies. 


Eliminated Norovirus floats in the air accompanied by diarrhea stool or vomitus.  If someone happens to be there, the virus enters the person’s body through the mouth and nose and begins to grow if it reaches to the intestine.  A faucet, doorknob, or food also transmits virus to humans.  If an infected person has no immunity to Norovirus, he/she will experience an onset.  Infected people will transmit Norovirus as carriers.  Thus infection will occur and spread from human to human.  


As shown in Table 1, an investigation in the United States, infection route of Norovirus is of great variety.  The number of food-borne Norovirus infection cases was 904, and that of non food-borne ones was 2590.  Food should be regarded as one of the prominent infection routes.


2) Classification of infections

Infectious Disease Law classifies infections into Category 1 to 5 as shown in Tables 2 and 3.




Ebola hemorrhagic fever, which became epidemic in West Africa in recent years, is classified into the most hazardous group of Category 1.  Infections of Category 1 are extremely dangerous with high infectivity and mortality rate.  Tuberculosis and severe acute respiratory syndrome (SARS) are in Category 2 which consists of infections that are highly infectious but less dangerous than those of Category 1.  Infected patients of Category 1 will be hospitalized in principle, and those of Category 2 will be hospitalized on an as-needed basis.  Category 3 is mainly composed of diseases caused by food poisoning such as enterohemorrhagic Escherichia coli infection.  Therefore, infected patients of Category 3 will be restricted to engage in certain jobs such as food manufacturing.  Infections of Category 4 are transmitted via animals or goods.  Animals of infectious source can be exterminated and transportation of infectious goods can be restricted.  Infections of Category 5 do not need to be imposed a restriction, but authorities will conduct the infection surveillance and publish the information in order to prevent the spread of infection.  Norovirus infection is comprised in infectious gastroenteritis of Category 5.




When infection-causing viruses/microorganisms are transmitted by food, the case will be registered as a food poisoning incident as well.  Therefore, the doctor that made a diagnosis is obliged to report to a public health center.  Enterohemorrhagic Escherichia coli infection, represented by O157, needs to be reported as a Category 3 infection as shown in Table 2 without any exception. 


According to the infectious disease surveillance by Ministry of Health, Labour and Welfare, the number of people who are reported by doctors as infected individuals is around 4,000 annually.  On the contrary, only about 300 people are reported to and registered by the Ministry as patients of enterohemorrhagic Escherichia coli infection each year.  I think the investigative method should be improved to precisely understand the occurrence of food poisoning.



1) Kitazato, Hara, Nakamura. Virus/Microorganisms Guide. Gijutsu-Hyohron (2016)

2) Watanabe. Trends and Response to Infectious Diseases in the World. Modern Media, 61, 313-323 (2015)

2) Watanabe. Trends and Response to Infectious Diseases in the World. Modern Media, 61, 313-323 (2015)

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