3980 Trust Way Hayward, Ca 94545(650) 208-8482; info@rayvio.com

8/23/2019

Client: LARQ Inc.
Job Number: JIV20190805-1
Study: Antibacterial efficacy of LARQ UV-C Pitcher against aqueous heterotrophic bacteria
Method: ASTM E2315
Report Date: 8/23/2019

Experimental Summary:
The purpose of this procedure was to test the effectiveness of the UVC function in LARQs pitcher at
inhibiting the growth of, and deactivation of aqueous heterotrophic bacteria in water samples. The
testing procedure was designed after discussions between LARQ and RayVio Inc. and is based on ASTM
E2315 (“Standard Guide for Assessment of Antimicrobial Activity Using a Time-Kill Procedure”) testing
guidelines and was conducted at RayVio Inc. in Hayward, CA.
Methods and Materials:
Two nominally identical LARQ pitchers were presented for testing (marked UV and no-UV.) The
products are configured to automatically deliver a predetermined UVC dose to the bottom reservoir ofthe pitcher every 6 hours. For the following tests the UVC function was active in one pitcher (marked“UV”), while the electronics were turned off in the second pitcher (marked “no UV”.) To further ensurethat the “no UV” pitcher did not receive an unintended UVC dose, electrical tape was placed over theUVC LED emission window. 1 ml aliquots were periodically taken from each pitcher and plated on
aqueous heterotrophic media plates. The plates were incubated at 37 oC for at least 48 hours before
counting CFUs.

3980 Trust Way Hayward, Ca 94545(650) 208-8482; info@rayvio.com

8/23/2019

First test – measurement of inhibition of aqueous heterotrophic bacterial growth
In the first test 400 ml of a sterile 0.05% Luria broth solution was added to each clean pitcher. Thepitcher marked “UV” had the UVC function active and automatically delivered a UV dose every 6 hours.
For the pitcher marked “no-UV” the electronics were switched off, and it received no UV treatment.
The table and graph below show the measured bacterial concentrations in the two solutions over time.

Time (hrs)
0.0
9.0
24.0
32.5
48.0
57.0
74.0

Measured CFU/ml
Measured log10(CFU/ml) Difference inUV
no-UVUVno-UV log10(CFU/ml)
00n/an/an/a000000200.30
0.30
0770
1.89
1.89
0
1,486
0
3.17
3.17
010,789
0
4.03
4.03
049,295
0
4.69
4.69

Second test – measurement of deactivation of aqueous heterotrophic bacteria
At the conclusion of the first experiment, the contaminated Luria broth from the “no UV” pitcher wastransferred to a separate container and 300 ml of sterile water was added to it. The two pitchers were
thoroughly cleaned with detergent and water, and left to dry overnight. At the start of the second

3980 Trust Way Hayward, Ca 94545(650) 208-8482; info@rayvio.com

8/23/2019

experiment 350 ml of the contaminated Luria broth solution was transferred into each of the pitchers.
Again, one pitcher received regular UVC exposures, while the other did not. At the start of theexperiment, a UVC exposure equal to what the pitcher delivers in normal operation was initiated for theactive pitcher. After that the active pitcher automatically initiated UVC exposures every 6 hours. The
electronics were turned off in the other pitcher and it received no UVC exposures.
The table and graph below show the measured bacteria concentration in the pitchers versus the numberof UVC cycles. The difference in the two curves at zero is due to the initial UVC dose.

Number of UV Cycles
Start
Initial UVC dose
135689Measured CFU/ml
UV
no-UV
68,00068,00016,00068,0004,416
85,0001,400
112,000
75
508,429
5780,000
2850,000
0830,000

Measured log10(CFU/ml)
UV
no-UV
4.83
4.83
4.20
4.83
3.65
4.93
3.15
5.05
1.88
5.71
0.70
5.89
0.30
5.93
05.92

Difference inlog10(CFU/ml)
n/a
0.63
1.28
1.90
3.83
5.19
5.63
5.92

3980 Trust Way Hayward, Ca 94545(650) 208-8482; info@rayvio.com

8/23/2019Conclusions:This study was intended to measure the effectiveness of LARQs UVC pitcher at both inhibiting thegrowth of, and deactivation of aqueous heterotrophic bacteria. The tables and graphs show that theLARQ filter pitcher’s UV function both inhibited the growth of aqueous heterotrophic bacteria, andachieved detectable reduction of aqueous heterotrophic bacteria versus the controls.

___________________
Faisal Sudradjat
Test Manager
RayVio Inc.
fsudradjat@rayvio.com