Industry
Shipping fermentation cultures between Canada and the US, what customs allows
Cross-border fermentation supplies Canada US shipping means CBSA and CFIA rules, customs declarations, duty thresholds and packing that keeps live cultures viable.
What to take away
- Mailing sourdough starter, kefir grains or koji spores between Canada and the United States is legal for personal amounts, as long as the parcel is declared by name.
- No import permit is needed for a personal amount of most cultures. Kefir grains are a dairy origin product, so expect an officer to ask about the source.
- Write "Fermentation culture, dried, 50 g, value 10 CAD" instead of "food" or "sample". Vague lines are the most common reason a small parcel is held.
- Canadian postal items valued at CAD 20 or less, and gifts up to CAD 60, arrive with no duty or tax. US-bound parcels under the USD 800 de minimis do too.
- A courier handling fee of roughly CAD 10 to CAD 20 can cost more than the tax it collects.
Personal mail across the border: the direct answer
Yes. A jar of starter, a pouch of kefir grains or a sealed packet of koji spores can be posted across the border as a personal exchange. Both countries treat them as food, and small food amounts move by mail and courier daily.
Identification decides the outcome, not the law by itself. An officer has to match the declared contents against the import list. "Food" or "gift" leaves nothing to match.
The Canada Border Services Agency inspects Canadian arrivals and assesses duty and tax. US Customs and Border Protection does the same on its side. Neither releases a parcel the recipient cannot describe.
The legal footing is written down rather than assumed. In Canada, the Safe Food for Canadians Regulations set what food may be imported and how it must be labelled, and the Customs Act sets how duty and tax are assessed when a parcel arrives. Both are published on the Justice Laws Website, where a seller or an officer reads the exact wording.
On the US side, two more agencies sit alongside U.S. Customs and Border Protection. The Food and Drug Administration controls food imports, and the U.S. Department of Agriculture's Animal and Plant Health Inspection Service controls animal and plant products. Food arriving in the US for sale is expected to carry FDA prior notice, filed by the importer before the shipment lands, and kefir grains are the item most likely to draw an animal-product question under APHIS rules.
Once a personal exchange becomes a sale, the rules change. A licensed seller shipping for resale meets requirements covered in how CFIA rules shape what home fermenters in Canada can legally sell, including labelling and source documents a gift never needs.
What must go on the customs declaration
A truthful declaration does most of the work. Six lines cover it.
- Name the goods and the formdried sourdough starter, kefir grains, koji spores. Skip the words sample, food and gift.
- Give the quantity and the value in the sender's currency. A symbolic value still needs a number.
- Complete the customs form by its own name. Postal items carry a customs declaration sticker, form CN22, or CN23 when the value is higher, and a USPS parcel uses PS Form 2976. Couriers file a commercial invoice and their own entry paperwork.
- Mark the shipment as a gift or personal exchange only when that is true. A false line can void insurance and lead to seizure.
- Put a paper note inside with the contents, the sender and the purpose. It helps if the parcel is opened.
- Keep the tracking number and a photo of the packed box.
"Fermentation culture, dried, 50 g, value 10 CAD" tells an officer everything. "Food" tells them nothing and invites a hold.
Health Canada's food safety information sets out the food obligations that sit behind the declaration.
Permits, the CFIA and the kefir grains question
The Canadian Food Inspection Agency sets the food safety, plant health and animal health requirements that the border agency enforces. A mailed culture must be a permitted food, from a permitted source, with accurate labelling.
For personal amounts, an import permit is unusual. The CFIA's Automated Import Reference System (AIRS) lists requirements product by product and country by country, so a sender can check kefir grains against the United States before posting. Where a permit is required, the CFIA is the body that issues it, and the application goes through the agency before the parcel ships; the permit sets the conditions and the labelling the shipment must carry.
Kefir grains are the item that stalls. They are a live dairy culture rather than a dried spice.
Kefir grains hold a mix of yeasts and bacteria, described in the Wikipedia entry on yeast, which is why they read as a dairy product. Declare them as kefir grains of dairy origin, say whether they are dried or fresh, and name the source.
A personal amount is usually released. A resale quantity can require an import permit and can fall under Canada's dairy tariff rate quota. An unlabelled culture is an unknown at the border, and four labels decide whether a batch works at home.
Koji spores, dried starter and tempeh starter sit at the easy end. They are dry food ingredients, and the officer's only real question is what they are. Plant health screening is aimed at living plant material such as cuttings, seeds and soil, so a sealed packet of food-grade spores is not the kind of item it screens.
Raw milk, raw cheese, unpasteurised meat ferments, soil and live insects sit at the barred end. Permits exist for a few of them, and refusal is common.
If you are shipping to a business rather than a friend, read the rules a food business follows that a home cook does not before you post.
Duty, tax and the handling fee the recipient pays
Duty and tax are separate charges. Duty follows the tariff classification and the country of origin. Tax follows the value and the destination. Classification comes from the Harmonized System, the same numbered headings both countries use, which is why the description on the form has to be exact. Most dried cultures and food ingredients carry a zero rate between the two countries when the origin is documented.
Duty, tax and the handling fee
| Where the parcel lands | Value | What the recipient pays |
|---|---|---|
| Canada, postal | CAD 20 or less | No duty, no tax |
| Canada, postal gift | up to CAD 60 | No duty, no tax |
| Canada, courier low value shipment | CAD 150 or less | No duty; tax waived on the first CAD 40 of value |
| Canada, above those limits | over the limit | GST or HST plus provincial sales tax plus a carrier fee |
| United States | USD 800 or less per person per day | No duty, no tax |
The carrier fee is not a tax. Couriers charge it for clearing the parcel, typically CAD 10 to CAD 20. On a ten dollar culture it can exceed the tax, so a gift may cost more to receive than to buy. The US side works the same way: the courier charges its own clearance fee, and a commercial shipment pays a broker to file the entry with U.S. Customs and Border Protection.
Sales tax rates follow the delivery address, not the sender's location.
Packing a live culture so it arrives alive
Temperature and containment matter more than shipping speed.
- Culture in a rigid, leak proof primary container
- Absorbent layer of paper towel or cloth around it
- A second sealed bag around the first
- Rigid outer box with padding on all sides
- Frozen gel pack in warm weather, extra insulation in winter
Never seal an active ferment airtight for shipping. Fermentation produces gas and pressure, and a jar that holds pressure will leak or crack. A padded envelope is enough for dried spores. A jar of liquid needs a box.
If you keep cultures at home between shipments, storing small batch ferments explains the temperature and headspace rules a parcel only imitates.
