Confectioneries are sweet, shelf-stable products with low water activity (aw), below 0.85. There are two kinds of confectionery: sugar confectionery and chocolate confectionery.

Their low aw makes confectioneries resistant to bacterial growth (see Konkel, 2001, 2015); however, bacterial survival in these products, e.g. Salmonella, is possible. Spoilage is due to the growth of osmophilic/xerophilic yeasts and molds unless the aw is below 0.61.

Sugar confectioneries include hard candies, toffee, caramel, fondants, creams, and pastes. Hard candies and toffee do not spoil due to their low aw. The rest of the products may spoil by osmophilic/xerophilic yeasts and molds.

Chocolate confectioneries are manufactured with cocoa and chocolate. Due to their low water activity (aw), they are spoiled by osmophilic/xerophilic yeasts and molds. Yeasts are the main cause of spoilage. Zygosaccharommyces rouxii and less frequently, Brettanomyces/Dekkera have been identified as cause of spoilage. These group of yeasts and molds can grow down to a aw of 0.61.


Spoilage of Confectionery Products

They can be spoiled by xerophilic yeasts and molds with yeasts being their principal cause of spoilage.


Fat blooms and sugar blooms on chocolate are physical defects that are frequently misdiagnosed as mold growth. Fat bloom is associated with improper temperature control. Sugar bloom is similar to fat bloom but it not greasy.

Although bacteria cannot grow in most confectioneries, pathogens are likely to survive in the product for several months after manufacturing. There have been reported several cases of salmonellosis caused by the contamination of chocolate products. Low levels (below 10^3) of Staphylococcus aureus or Bacillus cereus may be present but do not seem to indicate any health hazard at these levels.

For all processing plants of confectionery, raw materials, product formulation, thermal processing and the environment are control points. Proper cleaning and sanitation procedures must be used. Special care should be given to the control of xerophilic yeasts and molds in the environment avoiding confectionery residues on the equipment that can harbor these microorganisms.

Recommended tests

Aerobic plate count.
Total coliform and E. coli.
Osmophilic/xerophilic yeasts and molds.

Additional tests



Adapted from

Konkel, P. J. 2015. Confectionery Products, chapter 56, p. 555. In F. P. Downes and K. Ito (eds.), Compendium of Methods for the Microbiological Examination of Foods. American Public Health Association, Washington, DC.