Using eggs safely in homemade ice cream
Why raw yolks don’t belong in ice cream, why 71 °C is enough for safety while 82 °C is the cook’s upper limit for custard, and when to reach for pasteurised eggs.
Egg yolks turn ice cream into a thick, smooth and fragrant cream. An egg base (a custard base, in Slovakia sometimes called “French” ice cream) is one of the most popular homemade recipes. But eggs also bring a risk that is underestimated when it comes to ice cream: salmonella. Freezing doesn’t kill it, it only puts it “to sleep”. The good news is that the risk can be reliably removed with heat or by using pasteurised eggs.
Why raw eggs don’t belong in ice cream
Salmonella can be found on the shell, but according to the Czech National Institute of Public Health (Státní zdravotní ústav, SZÚ) it can also get through the shell into the egg. SZÚ also lists frozen products made with unpasteurised eggs among the high-risk foods. Washing the egg isn’t enough.
Did you know?
According to the Minnesota Department of Health, 17 outbreaks of salmonellosis with more than 500 people ill were linked to homemade ice cream in the US between 1996 and 2000. The source was raw or insufficiently cooked eggs.
Homemade ice cream is also often made for parties and for children – a group that copes less well with infections. That’s why zmrzka’s recipes don’t use raw eggs at all.
What temperature is safe
When cooking an egg base you’ll come across two numbers. It’s worth knowing that each means something different.
| Temperature | What it means | Source |
|---|---|---|
| 71 °C (160 °F) | safety minimum for an egg base, measured with a thermometer | FDA, Minnesota Department of Health |
| 70 °C for 10 minutes or 75 °C for 5 minutes | indicative Czech hygiene recommendation for heating the whole volume through | Prague Public Health Station (Hygienická stanice hl. m. Prahy; figure from a search, page not verified) |
| 82–84 °C | the cook’s limit for a custard base (crème anglaise) – the custard thickens; above it the yolks start to curdle | kitchen practice, zmrzka’s recipes |
According to SZÚ, salmonella dies after just a few minutes at 60–65 °C. The US Food and Drug Administration (FDA), however, gives as a practical rule that an egg base should reach at least 71 °C, checked with a thermometer. This reliably kills Salmonella Enteritidis too, the typical “egg” salmonella.
zmrzka’s recipes heat the custard base to 82–84 °C. Not because 71 °C isn’t enough for safety, but because at this temperature the custard thickens properly (“coats the back of a spoon”) and the ice cream is smoother. At the same time you can be sure you’ve passed the safety minimum with room to spare.
Warning
Above roughly 85 °C the yolks curdle and lumps appear in the custard. So don’t boil the mix – just heat it over a low heat, stirring constantly.
How to do it in practice
- Heat the milk (with the cream and sugar, if using) until almost boiling.
- Whisk the yolks with the sugar and, stirring constantly, pour the hot milk onto them in a thin stream.
- Return everything to the pan and stir over a low heat until the thermometer reads 82–84 °C.
- Immediately strain the custard into a bowl set in an ice bath and cool it quickly.
- Cover and leave to age in the fridge.
Tip
A kitchen thermometer costs a few euros and is the cheapest insurance there is. Drawing a line with your finger across the back of the spoon is a handy test, but it won’t measure the temperature.
Cooling quickly is just as important as heating. The Minnesota Department of Health recommends chilling the cooked base thoroughly. A warm custard left out on the worktop for a long time is an ideal environment for bacteria that get into it from the surroundings.
Pasteurised eggs and egg-free recipes
If a recipe calls for eggs that aren’t heated (some no-churn ice creams or mousses, for example), use pasteurised eggs. The FDA recommends them for all recipes in which the eggs would otherwise be raw or undercooked. In shops you’ll find them as liquid pasteurised yolks or whole eggs in cartons, and in some places as pasteurised eggs in their shells.
The other option is an egg-free recipe. Fior di latte–style gelato, sorbets, ice creams made from cream and condensed milk, or tvaroh (quark) ice creams manage perfectly well without eggs. Their creaminess comes from fat, milk solids or starch.
What else reduces the risk
- Don’t taste an undercooked base. Not even “just a little from the spoon”. Taste only once it has been heated to the right temperature.
- Use pasteurised milk and cream. Raw milk can carry pathogens (Minnesota Department of Health).
- Keep eggs in the fridge and don’t use cracked ones.
- Wash your hands after handling raw eggs and wipe down the worktop.
- Don’t leave the finished base at room temperature for long.
Warning
Take particular care with eggs in ice cream for young children, pregnant women, older people and people with weakened immunity. For them, always choose a thoroughly heated base or an egg-free recipe.
Summary
| Situation | What to do |
|---|---|
| Egg custard | heat to 82–84 °C, at least 71 °C, measure with a thermometer |
| Recipe with raw eggs | replace with pasteurised eggs |
| No thermometer | choose an egg-free recipe |
| Want to taste | only after heating, never the raw mix |
Eggs and ice cream belong together. Just give them enough heat, and then cool them down fast.
Sources
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