## Metadata - Real Title:: [Welp Here We Go Again....](https://twitter.com/SarahTaber_bww/status/1474425359634419713) - Author:: [[Sarah Taber]] - Via:: - Publication-Date:: - ReadwiseID:: 12428251 - Last Highlighted:: 2021-12-24 - Imported: 2022-06-02 from twitter ## Highlights ### id261779187 > Welp here we go again. > Click through for info on both Listeria outbreaks that are happening in romaine right now! > Yes, both :_) https://t.co/MQbpF0TkOV - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425359634419713) ### id261779188 > "Why so many lettuce outbreaks" > Lettuce (and kale, chard, spinach, leafy greens in general) have a really high surface:volume ratio. > That means more space for things to live on per serving. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425361211482115) ### id261779189 > Lettuce just picks up more of whatever's in the environment than other produce. > So if you have funky conditions at the farm or food handling facility, lettuce will tell on you :_) - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425362583019523) ### id261779190 > Why do outbreaks happen so often in romaine? > It's likely just because...a lot of people eat romaine. It's kind of fulfilling the general-purpose mass-market role that iceberg did 20-30 years ago. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425363723923457) ### id261779191 > However (for any epidemiologists in the crowd who aren't, like, busy with COVID) > here's an observation, as a field auditor, on why this might keep happening in romaine in particular? > Romaine Harvest Is Weird & That Might Be Why It Keeps Having Outbreaks: A Brief Summary. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425365082873859) ### id261779192 > "Normal" harvest for produce generally comes in 2 flavors. > You either pick it, put it in pallet-sized bulk bins, & stack them on trucks. Then they go to a packing facility to get washed, cooled, put into retail bags/cartons, & get shipped out to stores. > Like so: >  - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425366542532612) ### id261779193 > Or you do "field pack." Pick it right into retail containers, like so (thanks https://t.co/WP9XXP2z6W). > This is more for fragile crops like berries. Field pack takes longer, but makes up for it in not having half the crop get smushed when you dump it out at the pack facility. >  - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425368929001474) ### id261779194 > So those are the 2 "flavors" of harvest logistics. > You can see this 2-part divide reflected in how lots of outbreak investigations look for the contamination source. It's EITHER from dirty water at the farm (irrigation/spray water) OR the packinghouse. > https://t.co/G5GCW25Oeb - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425371223285765) ### id261779195 > But.........a lot of romaine is harvested a 3rd way. > It's a hybrid between the off-site food handling facility, and field pack, methods. > Behold the harvest rig: a mobile food-handling facility that travels through the field. > Kind of a Howl's Moving Castle situation. >  - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425372871643137) ### id261779196 > To be clear: I think in principle harvest rigs are good bc the drop-off point for the crop moves with the pickers. Instead of a drop-off point at the edge of the field so pickers have to constantly be running back & forth, like you have with tomatoes or sweet potatoes. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425374675243030) ### id261779197 > That said: sanitation-wise, they can combine the worst of both packinghouse & field pack. > They pick enough volume that they need to be at packinghouse levels of hygiene control. > But they're out in the field where you don't always have good access to clean water. : / - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425377041039363) ### id261779198 > That matters bc lots of romaine harvest rigs spray the crop w water during harvest. > Why: bc it's a desert & they're out in the field. It'll be a couple hours before they can get it to a cooler, so it needs a little water to keep it from wilting. > Source: https://t.co/oF4eqDdrxN >  - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425378571698180) ### id261779199 > If you've ever perked up sad produce at home by dunking it in cold water- same principle! > As it says in the video, the water SHOULD be sanitized. E.g. it should have low levels chlorine or other antimicrobials, like treated drinking water does. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425381612621836) ### id261779200 > This is for the same reason as drinking water: not a high dose that's supposed to sterilize whatever we spray the water on (like lettuce or ourselves while taking a shower), but a small amount that's just to keep the water from going funky in the pipes. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425382732447750) ### id261779201 > If the harvest rig is run properly, then it works. > The antimicrobials keep the water clean even though the rig crew is working for hours in the hot sun. And the water keeps the lettuce from getting dehydrated. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425384104087552) ### id261779202 > However............that can be a big if. There are at least 3 potential fail points here. > 1. Dirty water- low doses of antimicrobials only KEEP clean water clean. They can't un-funk dirty water. > 2. Getting the right dosage of antimicrobial out in the field. > 3. Biofilms. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425385207095299) ### id261779203 > 1. Low doses of antimicrobials don't help, if you start with dirty water! > If you're running one of these rigs, you have to fill the tank with CLEAN, POTABLE water before each harvest session. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425386385780736) ### id261779204 > This sounds obvious. But if you've ever worked in ag you know clean potable water can actually be kinda hard to come across. > But there's lots of nonpotable water sources! Irrigation canals, impoundment ponds, lots of CA farms have off-the-books wells that never get tested, etc. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425387518238722) ### id261779205 > Harvest rigs travel all over CA & AZ. If you're running one of these and you're running all over tarnation to keep up with harvest contracts > & need to refill in a hurry > how often are YOU gonna hit the road in search of potable water? vs draw from whatever "looks good enough." - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425388562538498) ### id261779206 > So that's one area where harvest rigs can run into trouble: water sourcing. > Another is (2), getting the right dosage of antimicrobials. > If the dose is too low, they don't work. If you get it too high, it can scorch the lettuce. So you have to get it right. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425389707628573) ### id261779207 > But the tools we have available for checking antimicrobial strength in the field- test strips- can be a little hard to use. > Like yeah USING them is simple but they don't give you a lot of resolution. If your target is 30ppm but these are the strips you have, good luck lol. >  - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425391347642369) ### id261779208 > The problem usually isn't the person in the field using the strips. > It's the person who buys the strips and gets the wrong kind- wrong resolution, wrong chemical (free vs total chlorine vs peracetic acid, etc), expired, or if they just "forget" to restock. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425393197326337) ### id261779209 > One farmer client had his staff "checking chlorine levels" with test strips for BORON for SWIMMING POOLS. > When I pointed out the problem he blamed it on an intellectually disabled farmhand. > I bout punched that guy in the face but now we're straying from the point - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425394375929865) ### id261779210 > Which is that it takes a lot of organizational & technical capacity to source clean water for harvest rigs, and keep it clean. > Again: it's totally doable! You just have to, you know, DO IT. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425395495768064) ### id261779211 > 3. Last but not least, biofilms. > (thread break- to be continued) - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474425396703727628) ### id261779212 > Biofilms: Or, Why Filling Your Harvest Rig Tank With Dirty Water ONE TIME Can Haunt You For Weeks/Months. > Most bacteria don't actually like drifting around in water, plankton-style. They like to settle down. On a solid surface. Put down roots. Make community. Have some kids. (: - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474441390130089989) ### id261779213 > Anytime you have a surface that's wet much of the time > for instance, the inside surface of a water tank > bacteria will tend to form a biofilm on it. > https://t.co/UAKwXQGGUO - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474441391166087169) ### id261779214 > The tl;dr on biofilms is once they attach to a solid surface, a lot of bacteria will make gums, protective slimes, etc that make them really hard to remove. > E.g. You can't scrub them off, and a low-dose antimicrobial cannot make them go away either. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474441392323809289) ### id261779215 > The way to keep biofilms at bay is basic tank hygiene: only put clean water in there, & use the right dose of antimicrobials. > That way biofilms don't get a chance to form. The only real strategy for biofilms is prevention. Cause once they form, GOOD LUCK getting them off. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474441393355595781) ### id261779216 > Harvest rigs with biofilm in the tanks might help explain the bizarre patterns we often see in romaine outbreaks. > Usually we can trace outbreaks back to a field, irrigation water source, or packinghouse. > But some romaine outbreaks seem to have no discernible pattern. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474441394462900229) ### id261779217 > That's somewhat consistent with harvest rigs. A lot of them are contractors. So they're not tied to a farm, or even a single brand of lettuce. > This might help explain how romaine outbreaks can cut across brands that have different fields & shipping systems. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474441395578544132) ### id261779218 > Anyway, if anybody's tempted to blast off about how harvest rigs are "evil agribusiness" pls remember a lot of them may be contractors- some big, some small, and the people crewing them are waking up at 3am to be bent over in the hot sun in the middle of nowhere. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474441396669067269) ### id261779219 > The point to take out of this: not "punish harvest rigs," but "working harvest rigs is a real job with real stakes & the people doing it should be treated that way." > Not as disposable labor to act as shock absorbers for all the time & money tradeoffs in the food biz. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474441397788938241) ### id261779220 > If there are any journos or epidemiologists looking to follow up on harvest rigs, the people with the most insight on how they actually work day-to-day are the people working them. > Upton Sinclair nailed it- food problems come from labor problems. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474441398812385290) ### id261779221 > .@UFWupdates and @EquitableFood both work at the intersection of consumer safety & working conditions. > I haven't worked with romaine fields in a few years, so they would be way more up to date on the technical side & "what the life of an itinerant harvest rig is like." - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474441399827320833) ### id261779222 > @UFWupdates @EquitableFood Again I'm a few years out of that particular game so if anyone knows of farm worker orgs that deals a lot with CA/AZ lettuce or harvest rigs, pls feel free to drop them in the replies. - [View Tweet](https://twitter.com/SarahTaber_bww/status/1474442933357236225)