I was recently asked about castor oil, and whether there was a need to buy “detoxified” castor oil for use in soap. I’ve used castor oil in my soap for a long time because it makes marvelous creamy lather (use level 4 to 10%), but I did some checking into the toxicity issue.
According to the wikipedia, Castor Oil article, the castor seed contains ricin, a toxic protein. Heating during the oil extraction process denatures and inactivates the protein.
CastorOil.in has a huge amount of information about castor oil, including information on the extraction process which explains the different types of extraction and other processes that may be used to purify the oil.
The CDC has a page about Ricin, the toxin that is contained in the castor beans. It discusses ricin poisoning and how ricin is made, but there is absolutely no mention of ricin poisoning from castor oil – only from eating raw castor beans, or being exposed to ricin manufactured from the wast material left over from processing castor beans.
The wikipedia also has an article about ricin which says:
The aqueous phase left over from the [castor] oil extraction process is called waste mash. It would contain about 5–10% ricin by weight, but heating during the oil extraction process denatures the protein, making the resultant seed cake safe for use as animal feed.
I also found an in-depth article about the castor bean plant, The Castor Bean: A Plant Named After a Tick. It’s a pretty amazing plant! The article says,
Those who occasionally take castor oil may be assured that ricin does not occur in the pure oil.
Types of Castor Oil
Castor oil be additionally processed to remove the odor (“deodored”) or the color (“bleached”) or to remove free fatty acids.
Castor oil considered by the FDA as GRAS (generally regarded as safe) and is approved for use in foods and also for OTC drugs (laxatives and facial preparations).
“Detoxified” Castor Oil
Based on all of that, my guess is that someone using the term “detoxified” castor oil is doing as a scare tactic to sell more of their product. It could be done intentionally, or they could be confusing it with castor oil that has been additionally processed.
Castor Oil in Soap
The castor oil available to most soapmakers in usually food grade. It certainly is safe for use in soap, and probably good enough to take internally (if you need a really good laxative!). It’s a great addition to cold-process soap. I wouldn’t make soap without it!
Good Manufacturing Practices
Part of GMP is making sure that you have specifications in place for each of the ingredients you use. In the case of castor oil, you should be sure to specify whether you want the castor oil you use to be deodorized, bleached or otherwise processed (or not). Most likely, you’d also want to specify that it is “food grade”.
Another part of GMP is having approved suppliers for each ingredient.
By having both these things in place, you can be certain that the castor oil (or any other ingredient) is of the quality you expect. If you need a new supplier, you have the specifications in place to ensure that you are getting the same quality of ingredient from the new supplier that you need and expect for produce the same quality of soap as you have in the past.
[Castor Bean image from: Agriculture Source]