New Establishment of the Japanese Industrial Standards (JIS) for Portable Microbe Imaging Scopes

1. Purpose of the new JIS

The current approach to observing microbes in food factories, food preparation or processing facilities and other sites does not allow employees to bring glass products into such facilities in order to prevent the potential risks associated with broken glass fragments. Due to this rule, employees are not permitted to bring microscopes using conventionally prepared slides into the facilities. Accordingly, employees who intend to observe microbes must collect samples of target microbes at the sites and observe the samples with a microscope after adjusting and culturing them in a room separated from the facilities. As this approach takes a long time to complete , related industries have been requesting new, simpler approaches for observing microbes.

Portable microbe imaging scopes are simple instruments for inspecting microbes and do not required prepared slides or adjustment or culturing of samples. Users of the portable microbe imaging scopes are able to directly mount samples that contain water on a sample stage of the scope and immediately observe them on site. Accordingly, they are expected to be utilized in a wide variety of fields, including food processing facilities, medical-care facilities, restaurants and educational institutions.

Against this backdrop, METI established JIS B7271 (portable microbe imaging scopes) as the standards for resolution and robustness of portable microbe imaging scopes so as to secure the reliability thereof and permit users to accurately make use thereof.

Characteristics of portable microbe imaging scopes

1. No need for prepared slides
   These portable microbe imaging scopes do not require a prepared slide, the tool required for the conventional observation of microbes with a microscope.
2. No need for adjustment or culturing of samples
   The current approaches to observing samples with a microscope require taking steps of adjustment and culturing of samples. However, these portable microbe imaging scopes allow users to directly mount samples on a sample stage of the scope and immediately observe the samples on site.
3. No need for image receiving devices (alternative use of a smartphone)
   These portable microbe imaging scopes make use of smartphones with a built-in camera or the like as an alternative device for the image receiving devices of the conventional microscopes and they do not need any image receiving devices for exclusive use by the portable microbe imaging scopes.

Portable microbe imaging scope

Example of images shown by a smartphone

2. Highlights of the new JIS

The new JIS stipulates the standards for resolution and robustness of portable microbe imaging scopes. The major provisions of the JIS are as follows.

1. Target scope
   Under the JIS, potable microbe imaging scopes should be optical equipment that: permits users to omit pre-treatments of bacterium and other microbes, e.g., setting of prepared slides, and immediately observe microbes at the site; and allows users to: observe microbes by connecting observation equipment to an image receiving device; and to visually observe microbes using observation equipment alone via an eye lens.
2. Field view diameter
   Under the JIS, they should allow users to observe target microbes with a field view diameter of 0.02mm or larger and within plus or minus 5% of the field view diameter that manufacturers in certain fields have designated.
3. Resolution
   Under the JIS, they should have a resolution of 1,000LP/mm or more in total of the resolutions of five points: the center of the field view and four peripheral sections around the field view.
   Note: The resolution of 1,000LP/mm allows users to identify the gap between streaks of lines in the width of 0.5 μm arranged at the interval of 0.5μm.
4. Shock resistance
   Under the JIS, they should work in a normal manner with no structural damage and keep a good field view diameter and resolution even after they have received a peak acceleration of 100gn, which is a level of shock resistance that a portable microbe imaging scope may receive while being carried or handled.
5. Resistance against high temperature and high humidity
   Under the JIS, they should keep a good field view diameter and resolution even after being exposed for 48 hours to an environment of 40 degrees of temperature and 93% of relative humidity.

3. Expected effects

These portable microbe imaging scopes are expected to: permit users in a wide variety of industries, including foods, medical care, husbandry, agriculture and fishery, to observe microbes at the site in a simple and easy manner; and to contribute to supporting such users from the perspective of safety and hygiene management.

Note: For the full text of JIS B7271, visit the website of the Japanese Industrial Standards Committee (JISC) and retrieve the JIS by inputting the term “JIS B7271.”