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

#9 Visible Cleanliness, Invisible Cleanliness


Professor Emeritus at Hokkaido University

Advisor at Japan Food Research Laboratories

Biography of Dr. Isshiki


Human beings eat living organisms except for salt and some food additives.  Living organisms sometimes contain ingredients unfavorable for mankind or transmit pathogens and harmful substances.  Many food-poisoning incidents are caused by microorganisms, and some microorganisms decay foods.  In order to prevent food poisoning or decay, it is important to “know both yourself (the eater) and your enemy (food-poisoning or putrefactive bacteria).”  We should understand the properties of the bacteria and establish measures considering how and by whom the food will be consumed.


 As shown in Figure1 and 2, code of conduct for food handlers is claimed to be 5S (Sort, Systematic arrangement, Shine, Standardize, Sustain).  Under this code, food handlers are required to be independent and self-disciplined, and to eliminate all the unreasonableness, inconsistency and waste.  5S can be described as follows. 


 1) Sort: Discriminate necessary items from unnecessary ones, and dispose of the latter.

 2) Systematic arrangement: Arrange all the necessary items so they can be easily selected for use.

3) Shine:  Clean your workplace completely.

4) Standardize:  Maintain your workplace appropriate for food-handling by carrying out a thorough Sort, Systematic arrangement and Shine and furthermore cleansing and/or sterilization.

5) Sustain:  Keep yourself healthy, mind your manners, observe the rules and disciplines of your workplace, and cause anyone no trouble.


This 5S counts for a lot in achieving “visible cleanliness” under food hygiene control.  Some food factories add and put importance on 2S, Scouring and Sterilization, and total 7S is determined as their code of conduct.  It is essential to maintain “invisible cleanliness”, hygiene control based on 5S, at workplace and home.  That is to say, both “visible cleanliness” and “invisible cleanliness” need to be maintained and preserved in pursuing hygiene control. 


“Visible cleanliness” is comparatively easy to be understood, but maintaining and preserving it at workplace or home is difficult in reality.  On the other hand, “invisible cleanliness” deals with “invisible” microorganisms I mentioned earlier in my column #1.  For example, “visible cleanliness” requires continuous pre-operation hand-washing, whereas “invisible cleanliness” calls for evaluations on microbiological effectiveness of the hand-washing.  It can be evaluated by “invisible indicators” such as viable count or amount of ATP and some countermeasures will be taken according to the results.


In order to make microbial control of “invisible cleanliness” more effective, basic knowledge of microorganisms are needed.  Microorganisms are striving to survive even under harsh environment.  Their way of life might be more valiant than that of humans in a sense.  Microorganisms are too small to be seen by the naked eye.  It is important to take into account the “invisible cleanliness” too in conducting 5S. 




Epidemiological studies have revealed that less than 100 severely pathogenic microorganisms, such as O157 or norovirus, can cause a disease if put in human mouth.  “Invisible cleanliness” cannot be maintained without appreciation for food together with measures against invisible microorganisms.  Human beings need to take in invisible vitamins included in foods.  Consideration of how and by whom the food at hand will be consumed, i.e. Vitamin I (love), is indispensable in conducting food hygiene control.


5S is effective also in reducing the disposal loss of food.  In Japan, no less than 5 to 8 million tons of food is disposed of annually.  If 5S is neglected, I believe the loss will show further increase.  At the moment, one person out of nine is suffering from hunger on the planet.  Let us carry out thorough 5S in order to be of any help to these starving people.  The non-scientific “food-safety” folly of “let us discard it just in case” will lead to a waste of next generation’s precious food.


References (all in Japanese)


Japan Food Industry Center: Hygiene and Quality Control Practice Manual for HACCP Framework Reinforcement (2014)


(一財)食品産業センター、「HACCP基盤強化のための 衛生・品質管理実践マニュアル」(2014年版)


FAO: World hunger falls, but… (November 14, 2014)

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