Best Practices for Preventing Microbial Contamination During Bottling
Last updated: 6/2021
Applies to: Beverage producers looking to ensure a final package that is microbially stable. Beyond filtration, there are several other considerations that should be taken into account, including several sources of potential bottling day contamination.
Bottling is a Critical Control Point
Bottling is typically the last critical control point before wine leaves the control of the producer. It is especially important at this stage to ensure that spoilage microorganisms are completely excluded from the final product. Two major components of this effort are:
- Good pre-bottling filtration practices (see Best Practices for Successful Filtration Prior to Bottling)
- Good bottling day practices to avoid contamination (especially if sterile filtration has already been completed).
Below are some considerations to avoid potential bottling-day contaminations:
Avoid Large SO2 Additions
Refrain from making large (>20ppm) SO2 additions right before bottling. Such substantial additions can potentially shock and shrink bacteria to a size small enough to pass through the final filter when enough pressure is applied. Instead, adjust your dissolved oxygen to the lowest possible levels (<0.5ppm) to keep the SO2 as efficient as possible and remember to re-check SO2 after sparging.
Sterile Filter Gasses
Chemical and microbial contamination from compressed gases is an under-appreciated risk during bottling. Consider the sterile filtration of all gases used during bottling or sparging.
Properly Clean Bottling Equipment
Bottling lines and associated equipment should be cleaned and sanitized at shut-down and again at start-up if a pre-determined internal cleaning. An external cleaning of the filler should be conducted at start-up, shut down, and at various time in-between (e.g. scheduled breaks, production downtimes).
DESTAINEX-LF is a great option for cleaning bottling equipment. It was specifically formulated for the wine industry to remove protein, color stains, and neutralize microbial contaminants. DESTAINEX-LF is compatible with all bottling line equipment materials; it’s non-corrosive, non-tainting to wine, and is fully biodegradable. Download the DESTAINEX-LF bottling line cleaning protocol.
Use "Clean" Water for Cleaning
Make sure your bottling line is cleaned and sanitized properly and frequently with clean water. The organisms that live in water are generally not beverage-spoilage organisms; However, water is a fantastic solvent and it can contain many other notable impurities.
Some of these impurities can cause scale on equipment, which can be hiding places for biofilms. They can also interfere with the efficacy of your cleaners. One option for water filtration is the SCOTTCART™ AQUA housing and cartridge filter system comprised of a three-stage filter ending with a 0.3μ cartridge to produce a microorganism-reduced, suspended-solid-free water.
Final Package Stabilization
It is important to note that sterile filtration does not lead to package stability due to possible bottling/canning equipment or package contaminations. An increasingly popular method to ensure final package stability is Velcorin® treatment. Velcorin deactivates spoilage microorganisms including yeasts that can cause refermentation, and others that may produce unacceptable sensory attributes. Due to the unique physical properties of Velcorin, a Velcorin doser is required to atomize it into the product at the point of packaging. For more information on using Velcorin, see "Velcorin for Wine Production" or "Velcorin for Cider Production."
Filtration and sterile filtration, while they don't lead to final package stability are still highly recommended for many reasons. One being that Velcorin is less effective if the microbial load is too high.