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Is detergent required to wash cutting boards?

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.

Sample

Cutting board after cutting raw pork (after removing pork)

Pretreatment

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.

Reaction composition
  μL Remarks (final concentration)
Enzyme: KAPA 3G Plant (2.5 U/μL) 0.8 2U/reaction
Buffer (×2) 8 x1
Primer F: beef/pork/chicken (100 μM each) 0.06/
0.06/
0.1
400/
400/
600nM
Primer R: beef/pork/chicken (100 μM each) 0.13/
0.14/
0.1
800/
900/
600nM
Probe: beef/pork/chicken (100 μM each) 0.03 each 200nM each
MgCl2(25mM) 0.8 1.25mM
Sample 1  
PCR grade water 4.7  

Reaction sample total 16μL

Program
Process Temperature Time  
Initial denaturation 95℃ 15sec  
Annealing/extension 60℃ 30sec 50cycle
Denaturation 95℃ 4sec

 

Results

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
  Tm
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