UV effectiveness

[Brent]

Reading the specs on the UV units that Leader offer, I see that most of them claim 90% effectiveness, but they are not up to NSF standards.

The NSF approved models kill 99.99% of what appears to be everything.

According to the bible, North American Maple Syrup Producers Handbook
(is there one for South America ? ) the bacteria double in population every 20 minutes. Shouldn't we be using the NSF standards or is our maple flavored bacteria so susceptible to the UV that we don't need to go that far ?

Do you think Leader or anyone else tested it or did they just decide this was the price range the market would bear and they couldn't see very many at double the price?

[gmcooper]

Brent I'm not sure where the effectiveness % actually came from. From talking with one of the maple dealers years ago they were recommending pumping thru a filter then thru the uv light then into storage tank. That would be only one pass thru the UV light. To get the 99%+ rating I'm guessing they are continuosly running thru the UV light. One of the older sugarmakers I knew said everytime you pump sap to move it you will get a little darker syrup from it. Maybe not a grade but darker. Who knows for sure. For some lights the temp of the water or sap passing thru had an effect on how much was killed. One light on the market required 68-70 degree liquid for optimum performance.

[WESTVIRGINIAMAPLER]

Brent,

I should know a lot more about this after the season is over and I will post the results.

[Gary R]

Brent, the bible also says that you have to use a UV that is made for sap. It says water UV's aren't effective. I don't know anything about them , but you might want to find out the differences. Good luck.

[Brent]

Brent I'm not sure where the effectiveness % actually came from.

I saw this on a web page from one of the 3 major makers that I was looking at today, Wedeco ( Leader ), Trojan or Sterilight. The detail spec sheets that came up in the PDF showed the differences.
The $359 to $459 units were all 30 u and not NSF certified and claimed only 90%

The $800 to $1100 units were 40u and NSF certified and claimed 99 point something % kills.

It's a cinch that Leader are not offering the more expensive units at $ 550.
The real question is do we care about killing everything or only specific stuff that rots our sap, and is it killed off as effectively
as possible with the lower power units.

Of coarse Leader don't publish specs or even tell you which Wedeco model they are offering, or even that it is Wedeco.

Maybe the factory (ies) will respond to a question. I'll give it a try.

[Brent]

Brent,

I should know a lot more about this after the season is over and I will post the results.

I am really interested to see the results of your test to see if you're getting your good preservation from the chilling or the UV or do you need both.

My wife and I debating whether we should spend $500 on a freezer, that we can make some use of out of season, or a UV that will do nothing for 48 weeks a year.

[WESTVIRGINIAMAPLER]

Brent,

Look in a trading times and pick up a $ 50 freezer or one free for hauling if you are just going to use it to freeze sap in.

What I am planning on doing is take two samples of sap as follows:

1 sample raw sap from the tank on the tractor
1 sample of sap after UV

I will set them side by side and test the sugar content of them after they have been sitting for different periods of time and compare sap quality. Hopefully I can get some pictures, might even try to use glass mason jars if I can get my hands on several. What I want to see is how long the sap lasts and the difference in quality after 1 day, 2 days, 7 days, etc.

I only have a short sap hydrometer, so the readings won't be perfect, but it will show if there is any difference and how much. No ice will be introduced into either sample and due to the fact my sugarhouse is on the north side and colder inside than it is on the outside most of the time, I may bring some samples home and sit them in my garage which is part of my house, but not heated directly and fairly cool and dark during the earlier part of the season so there will be no freezing and thawing of the sap.

[jemsklein]

WESTVIRGINIAMAPLER so are you going to have 2 samples one is uv treated and one isen't and set them aside and see which one goas bad the fastest

[jemsklein]

well i just found out some thing i have a extra uv unit in my basment that i canhook up for next years sugar season when the sugar shack is finished

[maplehound]

Brandon'
Sounds like an intersting experiment. However if you have only one hydrometer and you use it for both samples as well as for testing other sap won't it contaminate the UV'ed sap and spoil the results?

[jemsklein]

Brandon'
Sounds like an intersting experiment. However if you have only one hydrometer and you use it for both samples as well as for testing other sap won't it contaminate the UV'ed sap and spoil the results?

it should not as long as you sterilize it in boiling water or a alcohol swaps

[WESTVIRGINIAMAPLER]

A good rinse off and disinfect will take care of any problems like that. I am going to try to do this at least 4 times during the season and keep the sap each time until it is gross and see what happens.

I wish I had a long stem sap hydrometer to do the testing with, but I am not going to pay $ 30 to have one shipped to me and as I am 4 hours from a dealer.

[jemsklein]

what about ebay you could get one for like $2 i got a 3" thermometer 0-300f with 6" stem for a $1 and cost $4 more to get here

[ziggy]

I might be able to save you all some money. All of the UV lights currently on the market were tested by a major university and the amount of bacteria they kill in sap under the conditions we use them is 0 (zero), with the exception of one unit which is the unit sold by PHE and it kills 99.9%. It amazed me when I found this out. The rest of the units work under lab conditions where you can control the tempature and depth of the sap.

[mountainvan]

what university? when was it done? where were the results published? making a statement like that should be backed up with specific information.

[ziggy]

Study is not complete, but it is Cornell

[Brent]

I could not find a supplier with PHE in it with a Google search.

Got any further info where to find them ?

I would take a wild guess that this is going to relate to what I found, and that is that the 30u systems sold for sap and NOT certified by NSF (National Sanitation Foundation ) also do not have the narrow passage to give enough exposure.

I was getting close to ordering one and this has stopped me cold. I sure don't need another $500 mistake.

[ziggy]

Brent, I was not going to get in the middle of this post except that I knew there are several of you planning on spending money and I know I can't afford to waste money. It is Phil Hartman Enterprises. He was at VVS last year. I don't have his contact info but I can get it and post it tomorrow. I think his being at VVS last year is what got the study started.

[ziggy]

FYI, If you want to find out if your UV unit is working it is real easy. Collect a sample of the sap going into the unit into a steralized container and then a sample of the sap coming out of the unit and have them tested. Its is not real hard and very inexpensive. There are labs all over that can test the sap. Post your results, I would like to hear the results. Just because a study was done it does not always means the results are correct.

[Brent]

Easy ... all ya gotta do is buy the UV first.

Then as you say, there's a lot of ways to mess it up and come to the wrong conclusions.

Still can't find what unit they tested with. Most Phil Hartman hits are for the celebrity sites.

[gmcooper]

Ziggy,

Just reading thru this. Were the test done with the uv lights that are open and over the tank or were they enclosed that sap is pumped thru. I remember years ago the lights that were suspended over the tanks only killed bacteria in the top 1" or so in the tank and that was basically right under the light.
Interesting topic!
Mark

[ziggy]

The tests were done with the pass thru units. Your right they used to sell the units that sat over the tank and only worked on the top inch. What makes me believe the results as I have been told is this. If other studies proved that the units which sat over a tank of non moving sap only penetrated an inch and had a lot of time to do so. Why would the same UV light have any move effectiveness when it is working on a moving column of sap and has only a few second max to do the job. Granted there is a lot less sap to work with but still you can only get a max penetration of an inch. Just my thoughts.

[jemsklein]

well there is only like 1/2 inch that they need to penatrate

[Brent]

One of the net articles I read said something along the lines that NSF certified UV systems had only 1/4" max depth of water for the light to penetrate. They also had 25% higher ratings for the light exposure ( 30u vs 40u) and flow restrictors so the length of time the water was within the unit was controlled.

The net result was that NSF certified units killed 99.99% of everything that mattered and the less expensive systems only killed about 90 - 91%.

But the unknown is, do we care about killing the cytoplasts, and other things that I can't spell or pronounce, or just the stuff the feeds on the sugars, ... and how susceptible are they to the UV light. Could be the cheaper units will do the job. Could be the study compared the cheaper pass thru units to overhead bare bulb units.

We've got a lot of questions still.

[mountainvan]

Just got a bascom catalog. A blurp with the uv light said that uvm and cornell, francis morriclli, the uv light killed 80- 85% of bacteria.

[saphead]

A company not to far from me started using UV on cider a few years back and their system is the only one approved by " the powers that be". Cider now has to be pasturized,I don't know if this just in Ma. or nationwide.I works so well they adapted it to maple sap,it is called "Sap Steady". It is made by Orchard Equipment Supply Company,Inc.,Conway Ma. www.oescoinc.com. It has 8 germicidal uv lights inside a glass cylinder which is surrounded by another glass cylinder.The sap travels through this gap of .100" and the kill rate of everything is about as good as you can get.It is $$$ but I talked with a producer using one and he said it's like night and day as far as his RO membranes go and he makes a lot more Fancy which he needs for his candy,etc.

[WESTVIRGINIAMAPLER]

I think when Proctor originally did the study, they found that 86 to 89 percent were killed by the UV like most producers are using.

Just wait, I will have some results in about 6 weeks and we should know for sure.

[DS Maple]

I'm actually in the process of conducting tests involving maple sap and UV at the University of New Hampshire. One of our faculty members here happens to be a field leader in UV disinfection, having treated drinking water for over 1.6 billion people worldwide, but this is his first time dealing with maple sap.
Anyway, as many of you have mentioned, there are multiple factors that come into play in a situation like this. The two main types of machines do have pros and cons. While it can only treat the top in or two of liquid, a suspended UV light is on the other hand particularly beneficial in disinfecting the walls of the tank when it is empty. Bacteria from bad sap can certainly remain in a tank and contaminate sap of better quality.
Now to flow through systems. Obviously many different models of machines are available, ranging in the gpm that can be pumped through them. The posted gpm ratings are for water though, and are slower for maple sap. This has to do with UV transmittance and absorbance which in turn translate into UV dose. Despite its often similar appearance to water, maple sap acts very different under UV. While distilled water transmits around 100% of the UV light passed through it, my lab work currently shows that maple sap lets a maximum of around 40% of that light through. I did see (on a spectrophotometer) readings as low as 6% transmittance, but I will admit that the samples I tested came from trees this past fall and had been sitting for several weeks in a lab fridge before testing. (They still tested at around 2% sugar content though.) This spring I will resume lab tests with fresh samples and hopefully I will see a difference in transmittance, even if it is only a little difference. I briefly mentioned UV dose earlier, but neglected to mention that it is measured in millijoules/square centimeter. There are other units, but these are common for the US. Anyway, on the machines that would be used for maple, the only way to vary the UV dose is to adjust the flow becuase there is no adjustment for lamp power.
My plan for this coming spring is to determine an approximate UV dose for maple sap. I'm guessing it will be around twice that of water, given that average drinking water has a UV transmittance of around 85%.
Despite the fact that we have not yet completed all of the necessary lab work, I have installed a UV system in a sugarhouse for testing this spring. It consists of a UV reactor rated to 40 gpm that is installed in what I call a double pass system. Sap will get treated upon entering the sugarhouse and again in its route from the storage tanks to the evaporator. Testing the performance of the system is going to be rather difficult because we are a little unsure of what to look for, but we hope to see a stabilization of sugar content after the initial treatment.
That's what I've got right now. As new information becomes available I will post it. Also, I have picture of the sugarhouse system I installed and will try to post it if there is a demand.

~Scott
Environmental Research Group
UNH

[gmcooper]

DS Maple,

We'll be looking for updates and pics for sure!

I don't remember a sugarhouse at UNH when I graduated in 83'. Nice addition if you have one now!
Mark

[ziggy]

Saphead you are correct the sap steady is made by the company I have been talking about. They currently have more cost effective units on the market that work just as well.

DE glad to see more research is being done. One question, why run the sap through the UV and then in to the evaporator? once in the evaporator is will be steralized. Where I see the UV unit being used is more as a management tool. Run sap through the UV as soon as it comes out of the tubing system and then recirculate the sap back through the unit regularly to keep the bacteria counts down. This would allow us smaller producers to boil when it fit our schedule rather than when the sap runs.

I know of a large producer UV ing all of his sap as soon as it comes out of the tubing system and he can boil part of it right a way, keep the rest of the sap recirculating it regularly for 4 days then boil it and not loose any sugar content or grade of syrup

[brookledge]

I have a 12gpm unit that I pump my sap throughafter it comes out of the releaser and I also have a 3 foot long bulb that is suspended over my head tank. It is not easy to get to and I only clean it after the season is over. Before I used it the sides of the tank would be extremely slimmy now after the season the sides of the tank hardly have anything on them.
I might try what Brandon is going to do, I have a refractometer so I don't have to worry about cross contaminating the test sample by using a hydrometer. Another thing that would seem like it would happen is that if the bacteria feeds on the sugar than untreated sap should have a lower sugar content than treated sap therefore making less syrup.
DS maple keep us posted
Of course as the bulk prices of syrup are getting closer together all the time there is not such an incentive to make light syrup like there used to. A few years ago when you dropped a grade or two you lost alot of money now it is not much.
Keith

[DS Maple]

Ziggy,
I apologize for taking so long to respond. In order to answer your question we had a couple reasons for setting up the reactor the way we did. You're right that treating immediately before boiling probably won't do much in terms of the final product, but plumbing in the "double pass," as I described it, also allows for the sap to be cycled through the reactor and back into another tank by just switching a couple valves. If for some reason it has to sit for longer than expected, we can certainly treat it daily or twice daily if necessary. Also, in our particular setup the sap gets pumped from a larger storage tank in an insulated room up to another, smaller tank above the evaporator from which it gets gravity fed into the evaporator. We shut down when the large tank is empty, not when the gravity tank is empty. There is always sap sitting up there between boiling times and therefore it is kind of nice to give everything one last dose just in case. Not to mention the tank's location, being nestled right near the stack, which could result in higher than normal temperatures and therefore more microbial growth.
On similar note, for all of you out there interested in the technology, the machines designed for drinking water should perform just as well as those supposedly designed for sap. It's all about UV dose, which I'm sorry to say I have not pin-pointed at the moment, and all that really means is that the posted gpm is lower for sap than for water. The reactor we are using is a Trojan UV model F rated at 40 gpm. Right now I am guessing that pumping through at around half that rate or a little less should do the trick. Unfortunately though, the relationship between UV transmittance and UV dose is not linear but rather logarithmic, so it's not as easy as simply "half the transmittance=half the posted flow rate." Back to what I was saying before though, Trojan is one of the largest manufacturers of these units and they make many different models. I'm not sure of the exact prices because we had this one laying around, but I don't think that they are too overly expensive.

~Scott
Environmental Research Group
UNH

[Gary in NH]

I work in the water treatment industry and have some experience with uv applications. Germicidal uv lamps emit a certain amount of uv light output at a wave length of 254 nanometers. Different lamp and ballast combinations put out more or less uv intensity. Uv lamps have the greatest output when they are new and their output decreases from that point. The glass the lamps are made from will begin to "solarize" as the lamp is used. This solarization will steadily reduce the lamps uv output and transmission. It is similar to how sunglasses stop the transmission of uv a and uv b. This is the reason lamps need to be replaced every year. The lamps are usually enclosed in a quartz sleeve that serves as a barrier between the liquid and the uv lamp. Clean quartz sleeves are imperative for uv light transmission. As the sleeves get dirty the uv light can not pass through to the liquid as effectively and uv dosage decreases. When sleeves get dirty they can be cleaned with alcohol. A requirement for all uv light applications is the use of a 5-micron pre-filter. This prevents bacteria and other micro-organisms from being "hidden" or "shielded" from the uv light by particulate matter in the liquid. Uv light kills micro-organisms by destroying or damaging their cell DNA to the point that they can not reproduce or metabolize. Kill rate is determined by a combination of the strength or dosage of the uv exposure and the duration of exposure. Uv light systems for water treatment are primarily being used to kill coliform and e. coli bacteria. I personally would NEVER use a uv light for an e. coli problem. There is a reason that you will never see a uv light system rated higher than 99.9%. In regards to NSF listings. The manufacturer must submit their system for NSF approval under a particular NSF protocol or standard. It is very expensive to get this third party certification. Considering the potential number of units sold to syrup producers I would doubt that you will see a NSF certification for this. I am not aware of any NSF standard for sap treatment for a uv light but I have not researched it. In any case I see a benefit to using uv light for reducing the bacteria in raw sap. The most effective way to keep the bacteria count low would be to continuously re-circulate the sap through a flow restricted uv system with a particle pre-filter prior to the uv. If anyone is interested in getting a uv system I can get you pricing and have them drop shipped direct to you from most any manufacturer. I can also get replacement uv lamps and quartz sleeves.

Gary in NH
__________________

[Brent]

The Trojan system F that Scott referred to is available at about $600. It has a 116 watt bulb and 43" x 3 1/2" cannister. This one is NOT NSF certified and has a rating of 47 GPM and minimal monitoring.

Just for comparison the smallest NSF certified Trojan appears to be the Pro 7 which interestingly has only a 67 wat bulb and 29" x 3 1/2" cannister. But this one is rated for only 8.2 GPM and has more electronic monitoring.

It seems to me the best bang for the buck is the F model. Longer cannister for more exposure time in the chamber. Reduce the flow significantly to the same as the Pro 7 and you should give everything inside a real good dose. That would put you in the range of 500 GPH of sap treated and should keep up with almost all guys operations here.

Now is Scott could only tell us what the real effect on sap stability was, we'd now if we should have one on our systems.

[maplwrks]

Why would you want to spend all that money on something that really isn't all that effective? As I've said before, if you process your sap in a timely fashion you will make good syrup. I can think of a few items that would be better in the sugarhouse than a UV light...ie......filter press,...pan washers,...air injection,..new pan, the list can go on and on. Most producers here in Vt. through out their UV contraptions 10 yrs ago. If you've got money burning a hole in your pocket, look at streamlining your operation, leave the UV units on the shelf.

[Brent]

Well the key is, I can't process everything in a timely manner.

Last year I took off too many consecutive days from my day job. This year I hope to store a bit and boil every 3rd day or so.

But you're absolutely right, there are other great gizmos the sugar house needs.

[DS Maple]

I'm working on it, but I don't think that I will have all of the data together until the end of this coming maple season. Hopefully I will have some UV dose info within a couple weeks though.

And for the record, the person hosting our field testing likes to wait until Saturday to boil all of his sap. It's not an issue of time, but rather an issue of sales. A lot more people come by the farm stand on Saturday, and therefore a lot more people come check out the sugarhouse. A large percent of them, after receiving a small sample, do wind up purchasing syrup. In this case it really makes sense to have a UV system if for no other reason than the ability to publicize.

~Scott
Environmental Research Group
UNH