Carrots, Carcinogens and Social Media Myths

If you peruse our blog of scientific studies you will see there are plenty of things to be concerned about where U.S. food is concerned.  Carrots soaked in carcinogenic herbicide is not one of them.  Yet, according to a popular video currently circulating social media, that is a reality consumers need to be concerned about.  The social media post warns consumers that baby-cut carrots are “soaked in” bleach and a cancer-“aggravating” chemical (chlorpropham, aka trade name, “Bud Nip”) to extend shelf life (source).

These claims about carrots are inaccurate.  But if you eat potatoes from the U.S., you may want to read on…

Here are some fun facts on carrots, the antimicrobial treatment permitted for carrots in the U.S., and potatoes and the herbicide chlorpropham

 

.

bunch of carrots

.

First off, what are “baby carrots”, exactly?  According to industry experts that produce them, “baby cut”* carrots are specific varieties of carrots that are harvested earlier than traditional carrots.

.

*“Cut and peeled carrots, more commonly known as baby carrots, are made from specific varieties grown particularly for baby production. The carrots used in baby carrot production are long, slender carrots that are sweeter, more tender and have a slenderer core than traditional table carrots – and harvested significantly younger than table carrots.”

-Dana Brennan,VP, Grimmway Farms, the largest carrot producer in the United States (Source)

.

orange carrots

.

How are carrots cleaned and disinfected in the U.S.?  Baby-cut carrots and whole carrots are not soaked in bleach in the U.S.  Rather, carrots (including baby carrots) undergo an antimicrobial rinse in water containing chlorine…industry levels are reportedly similar to the chlorine amount present in most U.S. tap water.  To be specific, chlorinated water is used to clean all carrots, but no other chemicals are added or used in processing the produce.**

.

**Though not currently used on carrots, in 2015 the USDA approved an antimicrobial wash for produce (both non-organic and organic) called, “First Step+ 10” which is a combination of lactic acid, fruit acids, and hydrogen peroxide for use as a produce rinse for commercial food distributors.  The ingredients are all classified as Generally Recognized as Safe (GRAS) by the U.S. Food and Drug Administration (FDA). The wash has also been approved for use in Canada; is U.S. Department of Agriculture (USDA) certified organic; is biodegradable; and does not affect the taste, texture, smell, or appearance of produce. 

.

close up photography of orange carrots

.

Is the herbicide chlorpropham used on carrots of any kind?  Chlorpropham (aka trade name, “Bud Nip”) is not used on carrot crops nor on stored carrots in the United States.  In fact, the chemical is no longer authorized as an herbicide for crops in the United States.***

However, chlorpropham is still applied to certain potato varieties in the United States to inhibit sprouting and extend storage life (source). (Chlorpropham has also been used on spinach, peanuts, tomatoes, stone fruits and other vegetables, not to mention, the herbicide’s role in maintaining weed-free golf courses.)

***Chlorpropham (CIPC) was registered in the U.S. as an herbicide back in 1962, and was previously widely used on certain types of commercial pre-harvest crops (including spinach, carrots and onions) to prevent weeds in the field.  But with newer, more effective herbicides on the market, most of those previous crop uses for chlorpropham had ceased by 1990.  The current use of chlorpropham in the U.S. is for sprout control on post-harvest, stored potatoes and spinach  (sources: U.S. Environmental Protection Agency’s 1996 re-registration fact sheet; US EPA Pesticide Fact Sheet).

.

photo of pile of potatoes

.

♦ Chlorpropham use on potatoes in the U.S.: When used on stored potatoes, chlorpropham is delivered as an aerosol “fog” that coats the potatoes (and sticks to everything in the area, including the storage containers, walls and floors), and can help them last in cool conditions for as long as nine months without sprouting (source).  The U.S. Environmental Protection Agency (EPA) rules requires that it regulate how much chlorpropham residue is allowed to remain in potatoes. The Agency has reassessed the human dietary exposure tolerance on post-harvest potatoes and determined that the tolerance value should be lowered from 50 ppm to 30 ppm (source)****

By comparison, back in 2020 the European Union banned all uses of chlorpropham (CIPC) on crops or food products (source), [Article 46 of Regulation (EC) No. 1107/2009; Implementing Regulation (EU) 2019/989].

**** The EPA has assessed the dietary risk posed by chlorpropham. When risk was estimated based on tolerance level residues of 30 ppm on potatoes, the Anticipated Residue Concentration (ARC) for the overall U.S. population represents 42% of the Reference Dose (RfD). The RfD is the amount believed not to cause adverse effects if consumed daily over a 70-year lifetime. Any exposure level less than 100% of the RfD is considered to be an acceptable dietary risk. The most highly exposed subgroup, children 1 to 6 years of age, has an ARC which represents 85% of the RfD. Therefore, the EPA maintains that chronic dietary risk is minimal (source).

.

a variety of cancer awareness ribbons

.

Is chlorpropham (CIPC) carcinogenic?  Not officially–at least not according to the U.S. government.  Chlorpropham has been evaluated for carcinogenic activity in both the rat and mouse. No treatment-related cancer effects were observed in the study using mice, and the only treatment-related effects in the rat occurred at a dose considered excessive by the U.S. Environmental Protection Agency (EPA). A developmental study with rabbits resulted in increased embryo resorptions and post-implantation loss. A reproductive rat study affected growth and histopathological changes in the spleen, bone marrow, liver, and kidney. Chlorpropham tested positive in two out of four mutagenicity studies (source).

The EPA ultimately classified chlorpropham in Group E (evidence of non-carcinogenicity for humans) under the Agency’s cancer classification guidelines.  This decision was made despite the EPA recognizing that…

“Although chlorpropham is classified as a group E chemical (evidence of non-carcinogenicity for humans) according to the Agency’s cancer classification guidelines, one of its metabolites, 3-chloroaniline, is structurally similar to a known carcinogen, 4-chloroaniline. There are no cancer data available on 3-chloroaniline. However, the Agency believes it is appropriate to use the cancer potency (Q ) from 4-chloroaniline to gauge any potential risk from 3-chloroaniline. Based on the structure of the compounds, the Agency believes that 3-chloroaniline is probably, at most, equally as potent and not likely to be more potent than 4-chloroaniline.

Two risk scenarios were used by the EPA in the dietary cancer risk assessment. One scenario would be more typical of the nationwide risk to chlorpropham as this chemical is currently used. This scenario assumes that the average public is exposed to 3-chloroaniline solely through residues on stored potatoes.  (The EPA believes the cancer dietary risk from spinach is likely to be small compared to potatoes because of its lower consumption and lower residues.)  The cancer risk assessment from the typical nationwide scenario resulted in a risk estimate of 3 x 10 (-6 power) .  This risk estimate exceeds the 1 x 10 (-6 power) estimate of individual excess lifetime cancer risk generally considered to be negligible.  However, for the reasons noted below, the Agency believes these numbers likely represent an overestimation of risk:

1-Based on a study by Amdur, et al (1991), 3-chloroaniline would not be expected to be more potent than 4-chloroaniline.
2-Rat metabolism studies detected 3-chloroaniline but no 4-chloroaniline.
3-An oncogenicity study of chlorpropham in rats did produce an increase in testicular Leydig cell adenomas. These benign tumors were only observed at one excessive dose level (higher than the maximum tolerated dose). Yet none of the tumor types which have been observed in 4-chloroaniline data were present in the chlorpropham studies (i.e, the 3-chloroaniline that was present in the test was not observed having a similar mode-of-action effect).”

The EPA’s regulatory conclusion: The Agency has determined that the nationwide use of chlorpropham on stored potatoes to inhibit sprouting as currently registered will not cause unreasonable risk to humans or the environment and this use is eligible for reregistration.

It should be noted that citing lack of sufficient evidence, to date chlorpropham has not been classified as a human carcinogen by the World Health Organization (WHO) or The International Agency for Research on Cancer (IARC).

.

question mark on chalk board

.

So are U.S. potatoes coated with chlorpropham safe to eat?  You say, ‘poTAtoes’. I say, ‘poTOTtoes’.  The carrots aren’t looking so bad now, are they?

.