Preservatives & Antioxidants

Microbiological and oxidative shelf-life control for bakery, beverage and ready meals.

1 preservatives · 1 currently in North America stock

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How to choose

Selecting the right preservatives

Establish pH before choosing the active

Antimicrobial efficacy depends on the undissociated fraction, which shifts steeply with pH. Adding more preservative to a high-pH product will not fix an efficacy problem — you need a different compound or a reformulation that lowers pH or raises acidity.

Understand threshold behaviour

Most antimicrobials show a threshold rather than a linear dose response. Below the threshold, protection is partial and can permit adaptation; above it, extra preservative delivers little except cost. Identify the effective threshold in a challenge test rather than assuming linearity.

Match the mechanism to the failure mode

If the shelf-life failure is oxidative rather than microbiological, an antimicrobial preservative will not help. Oxidative control requires oxygen exclusion, chelators and free-radical scavengers, ideally a blend of lipophilic and hydrophilic antioxidants.

Preservation has two distinct failure modes, and they require different chemistry. Microbiological spoilage is controlled by acids, antimicrobials and reduced water activity. Oxidative spoilage is controlled by oxygen exclusion, chelation and free-radical scavengers. A product that fails on the shelf for oxidative reasons will not be fixed by adding a preservative. The most consequential variable is pH. Antimicrobial efficacy is governed almost entirely by how much of the active species is undissociated, which shifts sharply with pH. Choosing a preservative before establishing the finished product's pH is choosing blind — and it is the single most common reason a preservative trial underperforms. Dose is equally misunderstood. Antimicrobials show threshold behaviour rather than linear response. Below the threshold you get partial protection, which is worse than none because it allows surviving organisms to adapt. Above it, additional preservative often delivers nothing except cost and an unnecessary regulatory burden. Antioxidants work differently. They are consumed. An antioxidant that protects against oxidation for two weeks has been used up, and the product fails at week three. Lipophilic and hydrophilic antioxidants also protect against different oxidation pathways, which is why blended systems outperform single-ingredient ones.

Challenge testing is the only reliable dose setting

Rather than carrying a dose over from a similar product, determine the effective level by challenging the finalised formulation against the organisms that matter in your category, at your actual water activity and pH. Antimicrobial efficacy falls as water activity rises, so a level validated in a low-moisture cake will usually be more than necessary in a high-moisture filling, and occasionally not sufficient in a refrigerated ready meal.

Where a preservative is part of a hurdle approach rather than the primary control, it is worth establishing which hurdle is actually doing the work. Some combinations perform additively, some synergistically, and some antagonistically — and an antagonistic combination can make the product less stable than either component alone.