Lactococcus lactis

Lactococcus lactis suppliers and sourcing guide

Lactococcus lactis is a spherical lactic acid bacterium, formerly named Streptococcus lactis, and the main organism in mesophilic starter cultures for cheese, buttermilk and sour cream; the former subspecies cremoris is now a separate species, Lactococcus cremoris. Strains are grown by fermentation and sold frozen or freeze-dried. Dairy makers buy direct-to-vat starter blends dosed in units, and supplement brands buy single named strains at a stated CFU per gram. It is also the organism that produces nisin.

See suppliers What to ask for on the COA

Category: Probiotics, cultures and yeasts
Also known as: Streptococcus lactis · L. lactis · Lactococcus lactis subsp. lactis
Facts checked: November 2026

Forms and grades of lactococcus lactis

Suppliers sell different products under the same name. Specify the one you need.

Mesophilic starter blend
Frozen pellets or freeze-dried direct-to-vat cultures, often blended with L. cremoris and Leuconostoc, sized in units per volume of milk for cheese and cultured dairy.
Aroma (diacetylactis) strains
Citrate-fermenting strains, formerly L. lactis subsp. lactis biovar diacetylactis, used for the buttery aroma in cultured butter, sour cream and some cheeses.
Freeze-dried concentrate
Single named strain at a stated CFU per gram for supplements and fortified foods.
Bulk starter
Mother culture propagated in the plant before inoculating the vat, used by larger dairies instead of direct-to-vat sachets.

What to check on the COA

Compare each result with your own specification when the lot arrives.

Viable count (CFU/g): Plate count on M17 agar with lactose, incubated at around 30 °C, reported as CFU per gram against a minimum; some suppliers also report flow cytometry counts (ISO 19344). The count, not the weight, sets how much goes into each batch.
Identity: Species confirmed by 16S rRNA gene sequencing or a species-specific PCR, and the strain confirmed against the deposited strain by a strain-level method such as whole-genome sequencing.
Water activity: Water activity of the powder measured with a water activity meter against a low maximum, since viable counts fall faster in moister powder.
Contaminant microbiology: Enterobacteriaceae or coliforms, E. coli, Staphylococcus aureus, yeast and mold, plus absence of Salmonella and Listeria monocytogenes in a stated sample size.
Heavy metals: Lead, arsenic, cadmium and mercury by ICP-MS, mostly a reflection of the carrier and cryoprotectants in the powder.
Acidification activity: Time to reach a set pH in standard milk at a stated temperature, the culture house's measure of how fast the lot will work in the vat.

Storage, lots and expiry

Storage and shelf life

Frozen direct-to-vat pellets are kept deep-frozen at the temperature the supplier specifies (often -45 °C or colder), and freeze-dried sachets frozen or refrigerated, in sealed foil packs. Take out only what goes into the batch and do not refreeze thawed pellets or reseal partly used sachets for long. Shelf life is set by the supplier from activity and count data at the stated storage temperature.

Lots and expiry dates

Record the units or CFU, the activity test result and the culture's code for each lot, and keep the culture lot traceable to finished batches. Culture houses group strains into rotation sets to manage bacteriophage, so follow the supplier's rotation scheme and rotate stock FEFO.

Regulatory status

Facts from regulators and standards bodies, each linked to its source.

Health Canada's Probiotics monograph for natural health products lists Lactococcus lactis as a medicinal ingredient, and the licence application and label must give the strain designation.
Source: webprod.hc-sc.gc.ca (opens in a new tab)
FDA's GRAS Notice Inventory lists GRN 1088 for Lactococcus lactis strain KCTC 11865BP, notified by Cell Biotech Co. Ltd. for use in dairy products; it closed on December 15, 2023 with FDA having no questions. The notice covers that notifier's substance and intended use only.
Source: hfpappexternal.fda.gov (opens in a new tab)
The EU Novel Food Catalogue entry for Lactococcus lactis (POL-NF-09451) gives it the status not novel in food, as bacteria used as characteristic ingredients in fermented foods.
Source: ec.europa.eu (opens in a new tab)

This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.

Lactococcus lactis suppliers

Manufacturers and distributors whose own websites say they sell it.

We are checking lactococcus lactis suppliers now

Every listing is checked against the supplier’s own website before it goes live, so this list fills in over the coming weeks. The specs and COA checklist above are ready today.

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Frequently asked questions

What forms of lactococcus lactis can brands buy?

Common forms include mesophilic starter blend, aroma (diacetylactis) strains, freeze-dried concentrate and bulk starter. Ask each supplier for the specification sheet of the exact grade they quote.

What should the COA for lactococcus lactis include?

Expect viable count (CFU/g), identity, water activity, contaminant microbiology, heavy metals and acidification activity, each with its method, specification and result for that lot.

How should lactococcus lactis be stored?

What is the regulatory status of lactococcus lactis?

Health Canada's Probiotics monograph for natural health products lists Lactococcus lactis as a medicinal ingredient, and the licence application and label must give the strain designation. FDA's GRAS Notice Inventory lists GRN 1088 for Lactococcus lactis strain KCTC 11865BP, notified by Cell Biotech Co. Ltd. for use in dairy products; it closed on December 15, 2023 with FDA having no questions. The notice covers that notifier's substance and intended use only. The EU Novel Food Catalogue entry for Lactococcus lactis (POL-NF-09451) gives it the status not novel in food, as bacteria used as characteristic ingredients in fermented foods.

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