Preservatives - Your opinions

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This is incredibly interesting. I was asked today to research propyl paraben (and its relevance as a preservative in skin care products), and it's lead me on a merry chase. I stop in here, and see this thread. Another merry chase; preservatives, natural, synthetic, etc. I've read articles explaining the appropriate pH balances for bacterial growth (4 to 9) and thrive (5.5 to 8.5). Articles explaining the antimicrobial/antibacterial properties of essential oils, and their associated pH ranges. I've read about alcohols (ethanol is a beautiful thing, really, it's like hemp, incredibly useful!), both ethyl and fatty. Parabens, in many forms, are naturally occurring in fruits and vegetables like blackberries and cucumbers, and they are often used in multiples to cover multiple pH ranges to prevent bacteria growth across the whole pH range.

Sorry, I'm going off the chain into a pleasant level of geekery here. :shock:

What are your thoughts on grapefruit seed extracts, or other extracts/essentials that might be both antibacterial AND antifungal (ie antimicrobial)?
 
A myriad of blogs tout he information that GSE is contaminated with other anti microbial chemicals which actually gives it it's preserving properties. I'm inclined to think this might be true, but I don't believe things that people put on their blogs if I can't find the actual factual evidence behind it as bad information seems to pass around like chinese whispers. If only I could find the original study.
 
Well! <cracking my fingers and grinning!> Here are abstracts from several research papers, Saponista. The first is probably the most damning evidence about GSE.

***

The antimicrobial efficacy as well as the content of preservative agents of six commercially available grapefruit seed extracts were examined. Five of the six extracts showed a high growth inhibiting activity against the test germs Bacillus subtilis SBUG 14, Micrococcus flavus SBUG 16, Staphylococcus aureus SBUG 11, Serratia marcescens SBUG 9, Escherichia coli SBUG 17, Proteus mirabilis SBUG 47, and Candida maltosa SBUG 700. In all of the antimicrobial active grapefruit seed extracts, the preservative benzethonium chloride was detected by thin layer chromatography. Additionally, three extracts contained the preserving substances triclosan and methyl parabene.

In only one of the grapefruit seed extracts tested no preservative agent was found. However, with this extract as well as with several self-made extracts from seed and juiceless pulp of grapefruits (Citrus paradisi) no antimicrobial activity could be detected (standard serial broth dilution assay, agar diffusion test).

Thus, it is concluded that the potent as well as nearly universal antimicrobial activity being attributed to grapefruit seed extract is merely due to the synthetic preservative agents contained within. Natural products with antimicrobial activity do not appear to be present.

Source: Aspects of the antimicrobial efficacy of grapefruit seed extract and its relation to preservative substances contained. von Woedtke T1, Schlüter B, Pflegel P, Lindequist U, Jülich WD. http://www.ncbi.nlm.nih.gov/pubmed/10399191

***

Commercial grapefruit seed extracts (GSE) were extracted with chloroform. The solvent was evaporated, and the resulting solid was subsequently analyzed by high-performance liquid chromatography, electrospray ionization mass spectrometry, nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis (by proton-induced X-ray emission [PIXE] analysis).

The main constituent was identified as benzethonium chloride, a synthetic antimicrobial agent commonly used in cosmetics and other topical applications. This compound comprised 8.03% (n = 2) of the liquid GSE sample. Higher amounts of benzethonium chloride were found in powder GSE samples.

Source: Identification of benzethonium chloride in commercial grapefruit seed extracts. Takeoka G1, Dao L, Wong RY, Lundin R, Mahoney N. http://www.ncbi.nlm.nih.gov/pubmed/16159196

***

Grapefruit seed extract (GSE), derived from the seeds of grapefruit (Citrus paradisi MCAF.), is listed as a natural food additive in Japan. Products containing GSE are used as disinfectants made from only natural sources, especially after Japanese researchers found that GSE prevents the growth of norovirus.

On the other hand, recent overseas studies indicated that synthetic disinfectants, such as benzalkonium and benzethonium chlorides, were present in some commercial GSE products. To confirm the quality of commercial GSE products available in Japanese markets, we carried out comprehensive research to identify the major constituents of commercial GSE products which are used as food additives (13 products from 6 manufacturers), dietary supplements (5 products from 4 manufacturers), cosmetic materials (16 products from 10 manufacturers) and disinfectant or deodorant sprays (7 products from 7 manufacturers).

By means of NMR and LC/MS analysis, synthetic disinfectants such as benzethonium or benzalkonium salts were detected in most of the commercial GSE products.

Source: Survey of synthetic disinfectants in grapefruit seed extract and its compounded products. [Article in Japanese] Sugimoto N1, Tada A, Kuroyanagi M, Yoneda Y, Yun YS, Kunugi A, Sato K, Yamazaki T, Tanamoto K. https://www.ncbi.nlm.nih.gov/pubmed/18344660

***

More scholarly references are listed here: https://en.wikipedia.org/wiki/Grapefruit_seed_extract
 
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Commercial grapefruit seed extracts (GSE) were extracted with chloroform. The solvent was evaporated, and the resulting solid was subsequently analyzed by high-performance liquid chromatography, electrospray ionization mass spectrometry, nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis (by proton-induced X-ray emission [PIXE] analysis).

The main constituent was identified as benzethonium chloride, a synthetic antimicrobial agent commonly used in cosmetics and other topical applications. This compound comprised 8.03% (n = 2) of the liquid GSE sample. Higher amounts of benzethonium chloride were found in powder GSE samples.

1) very interesting excerpts!

2) Does the quote above suggest that the benzethonium chloride is being produced during the chloroform extraction or are they saying that the benzethonium chloride was added after the extraction? I am a bit confused here. I *think* they are saying it is formed during the extraction which is pretty amazing if it is!
 
I don't think so, Galaxy. The way I read it, the chloroform was just the solvent used to extract the b.chloride from the GSE. I don't read that there was any chem reaction w the chloroform nor that the b.chloride was added. Just a basic solvent extraction of chloroform soluble constituents in the GSE. But abstracts sometimes gloss over important details, and I don't have access to the full text to confirm. Ugh....
 
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Can you send me the link possibly? I still have access to my university email and I'd like to read this if its open to me.

Honestly, the not reacting makes more sense I was just curious from the excerpts you had here. If I *do* have access I'll try and see if I can send it to you so you can read it too.
 
Here is the full cite:
Identification of benzethonium chloride in commercial grapefruit seed extracts.
Takeoka G1, Dao L, Wong RY, Lundin R, Mahoney N.
J Agric Food Chem. 2001 Jul;49(7):3316-20

It's going to cost me $35 just to read the article. If you can access it through your university access for free, that's the way to do it.
 
These are the ones who run to sue because coffee is hot, and burns when spilled.

Can we please stop using this example as the poster child for frivolous law suits? The incident that it refers to wasn't actually a frivolous law suit at all, and the media completely misrepresented it.

Frivolous law suits are stupid, but I'd rather stick to mocking actual frivolous law suits.
 
Can we please stop using this example as the poster child for frivolous law suits? The incident that it refers to wasn't actually a frivolous law suit at all, and the media completely misrepresented it.

Frivolous law suits are stupid, but I'd rather stick to mocking actual frivolous law suits.

Sorry Flyby, if you have a better one to cite that will make the point please, by all means. . . (Yes I know the truth about the mcdonalds incident, however it is still used as an example. Most people understand the issue by citing that incident, even if the truth of the lawsuit was sustained. )
 
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