Series: Brief measurement
Is detergent required to wash cutting boards?
You use a cutting board when you cook. Some people simply wipe it or quickly rinse it with water because they do not want to use detergent during cooking. Although the cutting board seems clean after doing so, food sometimes remains on it. We checked the actual condition using a mobile PCR device.
Cutting board after cutting raw pork (after removing pork)
We rubbed a 30 mm square area using a cotton swab in the following state. (1) Pork has been removed. (2) Rinsed with water. (3) Cleaned using detergent and dried. The cotton swabs were soaked in 0.1 g of purified water for extraction, centrifugation was performed at 10,000 rotations* for 5 minutes, and the solution near the center was diluted 10 fold. The obtained solutions were used as samples to be measured.
|μL||Remarks (final concentration)|
|Enzyme: KAPA 3G Plant (2.5 U/μL)||0.8||2U/reaction|
|Primer F: beef/pork/chicken (100 μM each)||0.06/
|Primer R: beef/pork/chicken (100 μM each)||0.13/
|Probe: beef/pork/chicken (100 μM each)||0.03 each||200nM each|
|PCR grade water||4.7|
Reaction sample total 16μL
The indicator for pork increased in samples other than the sample of washing with detergent. This indicates that cutting boards need to be washed with detergent. Real-time PCR amplification curves observed in the measurement are shown in the figure below. The result indicates that the cleanliness (how meat pieces are removed) of cooking utensils can be measured using real-time PCR.
Measurement was performed using a multiplex of beef, pork and chicken.
*1 Primer/probe sequence
|Cow-Primer F 5′-CCCGATTCTTCGCTTTCCAT-3′ (20mer)||66.8|
|Cow-Primer R 5’-CTACGTCTGAGGAAATTCCTGTTG-3′ (24mer)||65.4|
|Cow-probe 5’FAM-CATCATAGCAATTGCCATAGTCCAC-BHQ1-3’ (25mer)||72.9|
|Pig-Primer F 5′-CTTGCAAATCCTAACAGGCCTG-3′ (22mer)||66.2|
|Pig-Primer R 5′-CGTTTGCATGTAGATAGCGAATAAC-3′ (25mer)||65.0|
|Pig-probe 5’ROX-AACAGCTTTCTCATCAGTTACACACAT-BHQ2-3′ (27mer)||70.2|
|Chicken-Primer F 5′-TCTGGGCTTAACTCTCATACTCACC-3′ (25mer)||65.6|
|Chicken-Primer R 5′-GGTTACTAGTGGGTTTGCTGGG-3′ (22mer)||65.6|
|Chicken-probe 5’Cy5-CATTCCTAACACTAGCCCTATTCTCC-3’BHQ3 (26mer)||70.3|
Made by Nihon Gene Research Laboratories Inc. Tm values are calculated using the nearest neighbor method. However, the calculation method of Nihon Gene Research Laboratories was used for the probes. Reference paper:Tanabe et al., A Real-Time Quantitative PCR Detection Method for Pork, Chicken, Beef, Mutton, Horseflesh in Foods. Biosci. Biotechnol. Biochem., 2007, 71(12), 3131-3135