Mitsuo Kato's column
Verification of Food Safety Using HACCP
--- 4 Types of Approaches ---
Mitsuo Kato, President, Foods Design Co. Ltd.
#3 An Example of How DOX Is Used
Case of a packed lunch factory
Test objects
A packed lunch factory uses the DOX system, a 30-sample testable unit.
At this factory, about 10 thousand packed lunches are manufactured and delivered to offices/homes every day. Manufacturing starts past midnight and finished lunches are delivered by noon. As the delivery area is considerably broad, some of the deliveries leave the factory as early as 9am. On delivery, empty lunchboxes delivered on the previous day are collected. In the course of everyday deliveries, it can't be helped that there would be some lunches that will need to be brought back to the factory. These returned lunches are used for testing. Testing starts in the late afternoon. When these lunches are tested, time has elapsed since intended customers were expected to eat them around noon. That means if the returned lunches pass the DOX test, there should be no problem with lunches that have already been consumed.
Testing method
There are two ways of inspecting; one in which each side dish is inspected separately, and the other in which the mixing of all the side dishes of the day is tested. The accompanying rice is also evaluated. For example, rice, dumplings, boiled radishes, and saut?ed Szechwan pickles and beansprouts are tested one day. The total number of microorganisms and coliforms contained in them are quantified in the test (viable counts are required to be less than 100,000 and 110 per gram respectively). Test results appear on a computer screen from around 9pm to midnight. Their numeric values are written in a whiteboard hung on the wall beside a work-shoe locker, which all workers will pass when entering the factory. When the worker in charge of preparation arrives some time past midnight, the previous day's data can be seen.
Verification of manufacturing environment is accompanied
The whiteboard shows not only the testing data of the previous day's packed lunch but also that of the manufacturing environment.
Verification of the manufacturing environment is conducted by an ATP smear test. Test objects are classified into two categories. The first category is the parts which have direct contact with food, such as inside of lunchboxes, iron pots, and mixing tanks.
Parts which come into contact with food directly are very important. After washing collected lunchboxes, they are sanitized by hot-air drying at the final process and the inside of these boxes are ATP-tested. Critical parts like this are specified as OPRP in the ISO22000 (key points of the general hygiene management program that must be verified by scientific approaches). If these parts fail a scientific examination, manufacturing must be stopped until rewashing lets the parts pass the examination.
Test values for the parts specified as OPRP must be under 200 when ATP-tested. Those at this factory usually have solid results of single digits. Another category of the test objects are those randomly selected by tester's senses. They include parts such as door knobs, surfaces of working tables, or conveyer belts. ATP-test values for these parts must be under 500.
The names and figures of two of these parts which fail the test are written in the whiteboard. Handle and power switch of the steam cooker are written one day. Workers engaged in other processes will see this and they will brace themselves thinking; "Well, handles and switches are red flags." Even if the test values for such general parts go beyond the acceptable limit, it is just required to wash these parts carefully thereafter.
Grasp the trend
By watching this whiteboard, trends of both verification activities of the manufacturing environment and bacterial tests of the products can be grasped. That is to say, results of both general hygiene management and HACCP programs are displayed in a straightforward manner using the simplest numerical values. Despite the fact that DOX can deliver the test results as quickly as in 6 hours, it is still after customers' consumption of the meal for packed lunch factories. However, obtaining the previous day's result/trend is much more useful in confirming safety than receiving the test results 3 days later.
6-hours' extra time allows powerful safety verification
If manufactured products are to be shipped on the following day, they can be tested with DOX in the evening. The test results will be delivered the next morning, and, in case of any problems, the shipment can be suspended. Also as DOX can deal with up to 60 samples individually, safety verification is significantly stricter compared to commonly-used culture tests which deal with only one sample. Production can be started after multiple law materials are confirmed to be safe 6 hours later. Furthermore, three different phases of products of law materials, partly-finished products, and finished products can be tested concurrently. Thus, DOX realizes solid safety verification.
Check the accuracy once in a while
It is recommended to check the inspection accuracy of DOX once in a while. For example, send samples from the same batch every quarter to an official inspection agency as a DOX test. By comparing the results of these two tests, find out how many errors DOX has. This will make the DOX testing more reliable. Accuracy checking is required in ISO22000.
