FDA Warning Letters this week: A dirty glove is a dirty hand

The week goes by and new letters come out. Below I’ve selected a few of the food-oriented warning letters and discuss/explain some of the more interesting findings.

Don’t know what warning letters are? Check out this post for a brief overview of what they are and why FDA sends them out.

A dirty glove is a dirty hand

This week I’m going to do something a little different, rather than review the entire contents of one or several letters, I wanted to address some common findings that showed up in some truly awful facilities that received warning letters recently. Among a huge number of general findings of insanitary conditions like dirty equipment, rotting food, and poor general upkeep, the FDA inspectors made some pointed comments about hand contact when gloves were used.

WL# 18-ATL-01

Subject: CGMP/Manufacturing, Packing or Holding Human Food/Adulterated/Insanitary Conditions
   You failed to ensure all personnel working in direct contact with food, food contact surfaces, and food packaging materials conform to hygienic practices while on duty to the extent necessary to protect against contamination of food as required by 21 CFR Part 110.10(b). For example:
 a.  Employees failed to maintain gloves used in food handling in an intact, clean, and sanitary condition as required by 21 CFR Part 110.10(b)(5). For example, an employee in the front kitchen was observed using gloved hands to assemble sanitized production equipment. This employee stopped assembly to manipulate the hose that had been on the floor and then resumed assembling the sanitized equipment without first washing and sanitizing or changing the gloves.
b.  Employees did not wash hands thoroughly in an adequate hand-washing facility at any time their hands may have become soiled or contaminated as required by 21 CFR Part 110.10(b)(3). For example:
i.    Multiple employees were observed returning from breaks without washing their hands or washed their hands and then put on hairnets and earphones, without first re-washing their hands, before resuming production activities in the front and back kitchens and the spice room.
ii.    Throughout the inspection the front and back kitchen mixer employees were observed touching non-food contact surfaces such as shovels, buttons, equipment, buckets, cardboard boxes, waste bins, drums, kettles, and tables with gloved hands, then using the same gloved hands, without first sanitizing or changing, to handle raw ingredients and subsequently handle finished product and food contact surfaces.
iii.    A production employee was observed after a break in production to come directly from the break area into the spice room, handle non-food contact surfaces including a door handle, tables, a screw driver and then handle food production equipment such as a mixer, paddle, and a hose without first washing or sanitizing their hands.
iv.    Employees were observed entering the front kitchen production room from the spice room, handling non-food contact equipment such as a radio, boxes, and a trash can and then not washing or sanitizing their hands before performing work that included their bare hands touching the interior of “(b)(4)” finished product containers.

WL# CIN-17-510879-04

Subject: CGMP Food/Prepared, Packed or Held Under Insanitary conditions/adulterated
Employees were not observed washing their hands thoroughly in an adequate hand-washing facility before starting work, after each absence from the work station, and at any other time when the hands may have become soiled or contaminated, as required by 21 CFR 110.10(b)(3). Specifically…Employees engaged in food preparation were observed leaving the food preparation area, retrieving additional ingredients or packaging supplies, and taking phone calls. The employees were observed changing their gloves between these events, but they were not observed washing their hands prior to changing their gloves.
So what risk do the findings pose?

So….here’s the deal. Hands are obvious and effective vectors for disease. In general we tend to focus on the fecal-oral route (fingernails and cheap toilet paper kill people, wash up friends), but in a food plant, it’s important to watch where employees frequently interact with areas where they might touch “unclean” spaces and bring things back to the product, like bacteria on a dirty pallet or allergens from a snack/lunch while on break.

What’s missing here to evaluate the risk is some context. Generally employees can move from sanitary “food contact” surfaces without having to “intervene” on their hands, and some of the surfaces identified such as equipment buttons or screwdrivers could very well have been sanitized at the beginning of the shift so that clean-handed employees could use them without issue. That would be an efficient approach to startup sanitation. However, the other findings like coming back from break or handling items on the floor or obviously dirty equipment is normally out of the realm of best practice, and based on the awful sanitary state of the plants mentioned in the warning letters, it’s very likely that those surfaces/practices resulted in frequent cross-contamination. Good auditor.

What about the gloves?

This is more interesting, FDA specifically went after both manufacturers for using dirty gloved hands, because gloves aren’t magical. However, in the second warning letter above, FDA was pretty strict in that they didn’t consider the glove change adequate as an intervention. The general thought process here is that if you take off a pair of dirty gloves, your hands get dirty in the process. Therefore putting on a new pair of gloves with “dirty” hands means that your new gloves get contaminated regardless.

The “gloves or no gloves” debate typically focuses on the fact that it has been shown that glove use actually reduces hand washing compliance in healthcare and food settings, because people think the gloves make their hands cleaner. While dirty hands get washed (eew, there’s dirt on my hand), dirty gloves get worn.

The other half of the risk assessment though is based on bacterial transfer rates. And on this half, it has been shown that bacteria transfers from food to bare hands at about a 10% rate while through a glove it only transfers at a 0.01% rate. So even if you contaminated your hands while taking off an old pair of dirty gloves, only a tiny amount of those bacteria would actually make it back through a new pair of gloves. Though that doesn’t matter if you then contaminate the contact side of a new pair of gloves with your dirty hands, and it has been shown that handwashing between glove changes reduces that incidence! BUT it turns out that surgeons do this to protect themselves from getting contaminated during surgery without handwashing when changing gloves aseptically, so it’s common practice in other aseptic fields!

*pant, pant*

So…it’s complicated. But there is a potential third option, even if it isn’t generally considered in the guidance (by the way, mandatory washing between glove changes isn’t actually codified anywhere, but is enforced guidance and part of GFSI schemes).

So we’ve concluded that putting on gloves with dirty hands results in dirty gloves. Fine. But once you’ve put on a smooth, impervious, surface that can be cleaned and sanitized, you no longer have a glove, but a “food contact surface” just like a spoon! And spoons (if visibly clean) can be sanitized before returning to use.

We know that, in general, current handwashing recommendations can result in a 2-3.5 log reduction of bacteria on hands. This is the best we can realistically hope to do with current practice, and we rely on handwashing to prevent either low levels of contamination, or to simply remove visible filth that carries higher numbers of bacteria. Further transfer to food depends on transfer rates that are highly variable, and actual food safety risk depends on what’s transferred and whether it has the ability to keep proliferating.

We also know that gloves can be removed with minimal transfer per medical literature, and that only 0.01% of bacteria will make it from a “dirty” hand through the glove. So we just need to take care of those pesky bacteria on the outside of the glove. Too bad there isn’t some kind of way we could quickly treat a visibly clean food contact surface…say a 5-log reduction in like, 30 seconds to a minute…

Enter glove/hand dips. A method where in critical areas you maintain a “bath” of sanitizer prepared to manufacturers specifications that will provide a 5 log reduction of pathogens on a clean surface. By changing your gloves and sanitizing them by dipping them in your solution, you can empiracally achieve a much higher reduction in organisms on the contact surface than you would achieve by de-gloving>handwashing>re-gloving. Even better, you can do it just as quickly has a hand wash and can put these hand dips in convenient locations. Basically, you treat your hands as if they were a utensil like a spoon instead of hands.

FDA references these “hand dip” or “glove dip” stations in the Food code (2-301.16), refers to them in guidance related to nut processing, warning letters, and specifically states in a risk assessment on sprouts processors (emphasis mine):

Hand dip stations are important to sanitize clean hands and gloves.

Important language distinction here is that they said “clean gloves”, they still need to meet a visibly clean standard for the sanitizer to work, but if there is no visible contamination, you’re ready to sanitize, and a fresh pair of gloves out of the box will normally meet this standard.

Hand dip stations are also referenced in some older FSIS publications.

So, from a scientifically validated approach, glove dip stations should be as or more efficient as handwashing between glove changes. Unfortunately because of the abundance of state and FDA guidance mandating a “wash” between glove changes, different auditors may be more or less open to this procedure even if it has been properly validated/verified. However, the entire point of HACCP or HARPC is that you can establish whatever procedures work best for your plant/process that can be substantiated scientifically. Try it out, collect enough data to demonstrate that it works, and slip this blog post in your citations if it helps ;).


Fuller, Christopher, et al. ““The dirty hand in the latex glove”: a study of hand hygiene compliance when gloves are worn.” Infection Control & Hospital Epidemiology 32.12 (2011): 1194-1199.

Montville, Rebecca, Yuhuan Chen, and Donald W. Schaffner. “Glove barriers to bacterial cross-contamination between hands to food.” Journal of Food Protection 64.6 (2001): 845-849.

Robinson, Andrew L., et al. “Adequate Hand Washing and Glove Use Are Necessary To Reduce Cross-Contamination from Hands with High Bacterial Loads.” Journal of food protection 79.2 (2016): 304-308.

Jensen, Dane A., et al. “Quantifying the Effects of Water Temperature, Soap Volume, Lather Time, and Antimicrobial Soap as Variables in the Removal of Escherichia coli ATCC 11229 from Hands.” Journal of Food Protection 80.6 (2017): 1022-1031.