Goal is to get rid of any bacteria and yeasts right away, so that when they go in, CFU count is minimized. There's a secondary goal in food production typically of shelf life, which means keeping any microbes at bay by using preservatives (sorbate, natamycin, benzoate are common ones, depends on usage)
There are a few common methods to accomplish surface microbial reduction
- Acid wash. Using one or more organic acids (lactic, formic, acetic, phosphoric etc) knocks down the microbial load. If you look at new washes for salad, there have been some recent patents with novel formulations for acid rinses. With multiple acid blend, there's a synergistic effect even at low to moderate concentrations.
- Peroxide. This is perhaps most common. Peroxide wash will kill
- Chlorine dioxide. Recent favorite in some applications due to its effectiveness and comparatively low concentrations needed, along with short contact time. A bit pricier, but very effective.
- Commercial blends. There are commercial products such as peroxyacetic and proprietary blends for this exact application.
- Other. Hypochlorite, metabisulphite, etc. Generally not best for delicate herbs.
Overall, what I like is
- Lightly dehydrate raw material. High aw, high moisture are not so great for oil. If brine marinate for cheese, not as big of a deal.
- Depending on solution, neutralize if necessary. Eg, sometimes if wash too acidic, may need to rinse in a second step. Not common though, it really depends on the entire production flow and ingredients and materials used.
- Spin dry, then air/sun dry
have to choose the ingredients carefully based on maximum flavor potential. EG, can't use basil stems, and if using basil, easier to use extracted oil + dehydrated basil than fresh basil leaves. Rosemary is pretty easy, it's very cooperative.