Food: Pet Food
UV dye dog food   (+10)  [vote for, against]
For luminous turds

I can provide this UV fluorescent sustenance to the dog, then when looking for the Richard the thirds in the leaves at night I can use a UV torch to detect them.
-- bhumphrys, Oct 19 2018

I Highly Approve; However if you could could combine your formulary with the <link> below (hint, hint) you would sent oodles of poodle noodles up into the nighttime sky for all to enjoy. Have Your People contact My People -- we'll do lunch... Helium_20Charged_20Dog_20Food
[Grogster, Oct 20 2018]

common fluorophores
[bs0u0155, Mar 06 2019]

Turmeric could work, it contains curcumin which is a modest fluorophore. It also makes it all the way through animals.
-- bs0u0155, Oct 19 2018

<link> and Bun! [+]
-- Grogster, Oct 20 2018

I'd go for polymer-coated quantum dots - much more fluorescent, indigestible, and available in a vast number of emission wavelengths. With a handheld UV spectrophotometer, and suitable qdot combinations, you should be able to trace the offending canine.
-- MaxwellBuchanan, Oct 20 2018

Is turmeric safe for dogs?
-- nineteenthly, Oct 21 2018

Is turmeric safe for cats ?

// With a handheld UV spectrophotometer, //

... on the far end of a long stick ...
-- 8th of 7, Oct 21 2018

// Is turmeric safe for dogs? //

Probably safer than quantum dots, at least. I've heard those are quite toxic due to their smallness (a bit like carbon nanotubes and asbestos).
-- notexactly, Nov 07 2018

I have an update here:

Excited and goaded into action by [bs0u0155]'s revelation relating to turmeric, I bought a mains powered UV LED lamp. After it had arrived from China I recalled that I didn't have any lamps with ES, only bayonet, but invested in an E27-B22 converter. When it in turn arrived from China I was up and running and with the assembly installed in my inspection lamp even more eager to give the idea a test drive.

I can confirm that [bs0u0155] is correct, but slightly disappointingly under UV LED illumination turmeric powder only seemed weakly fluorescent.

I added a teaspoon per meal for a couple of days. The dog, being a sprocker spaniel, hungrily devoured the meals. I couldn't discern any consequent side-effects on the canine. I retained the following day's poop for thorough examination.

With my lamp, and with heart pounding, I illuminated whilst -quite closely- examining the turds.

Unfortunately the finding was that the sh**t was not particularly fluorescent.

Wondering whether it could be a 'skin effect' perhaps caused by an anal gland coating or some concivably complex sort of digestive processing foible, I carefully scraped the top layer from one of the jobbies to reveal fresh substrate. There was no perceptible difference. The glow was if anything dimmer than a toc-h lamp.

I waited a couple of weeks for the dog eggs to go a bit fluffy with mould, wondering whether the mould could perhaps concentrate any UV pigments into its hyphae. There wasn't any increase in the luminosity of the doggy dump.

Back to the drawing board....

I noticed that my uranium glass trinkets glowed extremely vividly under the illumination. Do you think, if it were ground down and powdered to a fine talc and buried inside a Bonio biscuit, U- glass could work in the task of making the poo stand out and contrast more against the undergrowth under UV illumination?
-- bhumphrys, Mar 04 2019

Bun for experimentation (and having the stomach to deal with dogshit...).
-- neutrinos_shadow, Mar 05 2019

Could you still taste the Turmeric flavour?
-- AusCan531, Mar 06 2019

// Is turmeric safe for dogs? //

Perhaps scorpions in a blender as an alternative?
-- AusCan531, Mar 06 2019

Try putting a bit of fluorescein in their food. It's pretty safe.
-- MaxwellBuchanan, Mar 06 2019

//[bs0u0155] is correct, but slightly disappointingly under UV LED illumination turmeric powder only seemed weakly fluorescent.//

//day's poop for thorough examination.//

Oooohh... that's going the extra mile.

So curcumin, the fluorescent component does respond to UV a little, but its main activity is in the absorbance of blue (~430nm) light to emit a greeny-orange color (550- 600nm).

So, you'll get WAY more emission brightness with a 395 or 455nm LED, they do flashlights with these wavelengths...Some advertised as being dog-pee detecting, we're developing a whole dog waste visualization system here.

The reason fluorescence is popularly associated with UV, is because we can't see the UV excitation light, only the visible light that comes back from the fluorescent object. That's usually combined with a darkened room to increase the eye's sensitivity. When using blue light, you can see it, and your iris closes and you lose the sensitivity needed for detecting the emission. So we need a strategy to selectively see the emitted light without being blinded by the excitation light.

One way is to manipulate the orientation of illumination vs observation. You want to minimize the amount of light going from the excitation source into your eye, so illuminate from the top/side or even better directly away, which suits the flashlight turd-hunt scenario.

For better selectivity, you want some glasses that block the excitation light, even better, glasses that block everything outside the greeny-orange. These exist for a few $ as far as I can tell.

That's the rig dialed in, let's have a look at enhancing the signal. First off, turmeric is mostly not curcumin. It's about 2-6%, the rest is mixed carbohydrate and planty type stuff. So, you can extract the curcumin with a hydrophobic solvent, alcohol works. Grind, add ethanol, shake for a while, filter and then you can evaporate off the solvent for a significant ~20 fold enrichment. I can't find specifics, but there's no evidence of toxicity in dogs (no data, but mentioned in a curcumin rat study) and there's studies giving 5% of the total food weight in turmeric in mice, rats, pigs and monkeys. No acute effects.

There's other fluorescent foods, canola, olive oil <link> and quinine. Although you'd imagine the oils would be absorbed and the quinine is both absorbed and pharmaceutically active.

//Try putting a bit of fluorescein in their food. It's pretty safe.//

It's absorbed pretty well, they use oral fluorescein for angiograms and the like. It's then excreted in urine, which is useful if anyone tries to poison you with antifreeze. 1, you may notice the fluorescent drink. 2 You may also notice the fluorescent pee. Rhodamine, another fluorophore, distributes quite messily, some in hair/tissues, some fecal, and some in urine.
-- bs0u0155, Mar 06 2019

//olive oil// As far as I can see from the picture, olive oil seems to emit in the black part of the spectrum.
-- MaxwellBuchanan, Mar 06 2019

Maybe they confused olive oil and engine oil...
-- neutrinos_shadow, Mar 07 2019

// they use oral fluorescein for angiograms and the like. It's then excreted in urine, which is useful if anyone tries to poison you with antifreeze. //

What if they poison you with antifreeze that doesn't have fluorescein?

An alternative approach to making dog poop fluorescent: Genetically engineer bacteria that prefer to eat dog poop and are fluorescent. Feed them to your dog to get them into the gut flora, or spray them on the ground where your dog poops.
-- notexactly, Mar 07 2019

//Genetically engineer bacteria that prefer to eat dog poop and are fluorescent.//

The likelihood that you can make a bug that's consistently more successful than any of the ones already there is quite low. Even if you took an example already present, then adding the extra load of the fluorescent protein would make it lose to its wild type relatives.
-- bs0u0155, Mar 07 2019

[bs0u0155] Calling you shirley, wouldn't something in the simple surface protein expression be better than going for a flashy but crippling, heavy metabolic pathway.
-- wjt, Mar 08 2019

That's okay as long as you're replenishing said bacteria regularly.
-- notexactly, Mar 08 2019

Perhaps you’re looking at the problem backwards. Simply sprinkle fluorescent powder around your yard beforehand then look for the black holes deposited upon it by your dog?
-- AusCan531, Mar 08 2019

Now _that_, [AusCan], is exactly the sort of lateral thinking that can get a man sectioned.

Another option would be to buy a bunch of fluorescent plastic beads and mix them with the food. They'll go right through, and a few of them will end up on the surface (of the poop, not of the dog). If you're feeling really frugal you could probably even re-use them.
-- MaxwellBuchanan, Mar 08 2019

random, halfbakery