An update on Herbal-Active® - a natural preservative
This email is an update on Herbal-Active®, a new natural preservative beginning to replace benzoates and sorbates in a wide range of foodstuffs and cosmetics.
Natural preservatives pose a host of challenges in developing their application potential. As with chemical preservatives, the presence or absence of organic matter, liquid phases (oil and/or water), pH, microbial loads and processing temperatures amongst many other parameters all contribute to the anti-microbial efficiency and the desired length of stability under different packaging and storage conditions all have their influences.
To fully understand if a natural preservation system will work for a specific product, direct tests are essential. No academic data or in vitro tests can replace in-product trials and shelf life evaluation.
Here are some recent findings in actual product trials:
Fresh store-bought chicken (skin on) was used as a medium and either sprayed with the Herbal-Active® solution or dipped into it. Swabs were taken from controls and treated meats immediately on treatment; after 30 minutes; and after an over-night incubation at chill temperature (4°C).
The control had a total plate count of 500-600 cfu/g; E. coli was at 75-80; and negligible colonies of Staphylococcus.
After spraying the chicken with the prepared Herbal-Active®, the total count was little changed but E coli dropped to less than 5 cfu in the samples left for 30 mins and overnight.
However, after dipping the total counts dropped dramatically reducing the E. coli from 75 – 80 cfu down to less than 5cfu/g in each case.
The porous chicken skin provides a challenging substrate to sanitize as microbes see it as a condominium accommodation matrix occupying the surface, underside and all the way through the cellular structure.
Some pork meat was left to rot in the refrigerator until highly (and unpleasantly) odorous. The tpc was 20 million cfu/g; the E. coli was 30,000/g and Staphylococci was 1000 cfu/g.
Spraying this meat dropped the tpc to 40,000, the E. coli to 20,000 (negligible) and the Staph remained the same at 1000.
However, dipping this pork yielded a dramatic reduction in tpc to 1000cfu/g and under 5 cfu/g for both, E. coli and Staph. There was no difference between the meat being just dipped or left overnight in the solution before swabbing.
These results demonstrate that dipping foods into Herbal-Active® even briefly, can significantly reduce the total plate count, E. coli and Staphylococci loads (both indicators of human contamination). The chicken meat dipped with this solution had no discernible flavor from the H-A on cooking as there was a dilution effect on the surface coat with the chicken as it was chewed.
Additional work is continuing to assess efficacy of this dip against Listeria and Salmonella.
USP PET update
Test results just in after a month of lab work – E.coli at 520,000 cfu/g were inoculated into various concentrations of Herbal-Active®, the lowest being 0.05%. In all test samples, the E. coli dropped to less than 10cfu/g after 14 days and after 28 days. This supports our previously reported NATA results of effective control of Candida albicans, P.aeruginosa and S. aureus at a minimum test level of 0.05%. Mould testing of our new formulation is continuing with encouraging initial results.
The challenge for manufacturers of pasteurized beverages is to control low numbers of yeast (and mould) cells which can grow over time affecting shelf life of bottled products. Additionally, some nutraceutical beverages and dairy drinks can have less than ideal pH levels. The approach is always to aim at a pH of 3.5 in pasteurized product and then Herbal-Active®, even down to a level of 0.01%, will provide preservation against the few yeasts remaining or reintroduced during bottling. However, it is recommended that taste test be conducted to ascertain the highest tasteless concentration for your particular product, expected to be around 0.05% for juices, for example.
The use of concentrates makes the process easier and more effective for mould protection. Herbal-Active® at 0.5% is able to reduce mould numbers significantly. Diluting this pre-treatment strength solution by 1:10 or more will render it tasteless as it adds shelf life even to cold formulated products. The degree of dilution will depend upon the flavor of the finished product and could be anywhere from 0.03% up to three times this amount for more flavoured beverages.
Another chemical group which Herbal-Active® appears likely to also replace are sulphites and sulphur dioxide since it has both anti-microbial and antioxidant properties. However, application rates in wines, for example, will be around the 0.05% level and so the effectiveness of the antioxidant effect is currently under scrutiny. It is certainly an effective preservative against fermentation at this level in wine.
Dry rubs, marinades and seasonings can easily be blended with Herbal-Active® up to 0.1% and even higher due to the dilution effect of small additions of the end seasoning as surface coats and inclusions to meats, snack foods and cheeses etc. Strongly flavored foods can also utilize Herbal-Active® at this concentration as the taste will blend with many commonly used herbs and spices. As is commonly known, herbs and spices themselves can carry high microbial loads while conventional anti-microbial methods such as steam treating or gamma irradiation or more novel methods such as volatile head space treatments can affect the quality of the flavors.
Herbal-Active® is currently being used as a means of controlling unwanted moulds on ripening cheeses (0.5 to 1% as a wash); as a natural antimicrobial in bottled marinated cheeses (at 0.05 to 0.1%); and has successfully been used in cream, yoghurts and other dairy products to enhance shelf life.
We also assist in trouble-shooting applications so please, if you have a product which needs the chemical preservatives replaced, just email or call and give us a chance of solving your challenge – naturally.
Case Study: The challenge of mixtures
Currently in test is humus which is an emulsion of 20% oil from sesame seed paste and 50% water, mostly from the cooked chickpeas. A previous formulation (less active against moulds) supplied as an emulsion and diluted to a working solution with ethanol gave the product several weeks shelf life. However, we needed more. Neither a straight water miscible nor oil miscible Herbal-Active™ in the new anti-mould mix quite did the trick individually, so currently in test is a dual application of them both. We predict that this should achieve the 3 months shelf life and even provide some antioxidant protection to the oil.
A concentration of around 1% Herbal-Active® is recommended for cosmetics and while this level will have a detectable herby note, the aromatics can easily be masked with conventional cosmetic fragrances.
To summarize, the work to date proves that Herbal-Active® is an effective natural preservative for foods, beverages and cosmetics. While it is not always a dump and stir solution, a methodology of approach is developing to apply this new natural preservative to the many products currently using benzoates and other undesirable chemical preservatives.