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In the Homemade Eggnog {Non Alcoholic} eggnog recipe featured on the website Annie's Noms as part of the recipe the author makes the claim that at 70 celsius the eggs are safe to eat. As below

  1. Keep stirring and cooking gently until the candy thermometer reaches 160F/70C – this is the temperature at which the eggs are safe to consume.

So are eggs safe to consume once they reach 70 degrees celsius?

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This is a question that would be better handled by the experts at Seasoned Advice (I suspect it would be a duplicate.)

Their food safety tag description is a fantastic resource that I commonly refer to, correcting a number of myths and misconceptions. From there, we can see the answer to this question is not a simple "yes or no" - heating them once to a certain temperature doesn't render them safe.

  • Bacteria leave behind harmful protein toxins that cannot be "killed" (denatured) by cooking. The cooking times/temperatures are only effective against live organisms, not their toxic waste products. Spoiled food cannot be cooked back to safety and must be discarded.

  • Cooking is pasteurization, not sterilization. Pasteurization means killing most microbes, so as to render the food safe for human consumption. This resets the clock but does not stop it; cooked food can and will still spoil after 2 hours in the danger zone. Sterilization methods (e.g. high-pressure canning and irradiation) are the only safe methods for longer-term room-temperature storage.

Egg safety is a regional issue, with eggs being stored (in production) at different temperatures and use different Salmonella control regimes.

The US government do recommend heating eggnog until it reaches "an internal temperature of 160 °F" (71 °C) to protect against infection.

This paper shows that 40°C for 2 hr or 48°C for 30 min was not enough to eliminate Salmonella enteritidis.

This paper discusses different treatments:

The US Department of Agriculture set-up pasteurisation standards for egg products that any Salmonella species in the egg is reduced by an amount equal to at least 5 logs. At present, LWE [Liquid Whole Egg] is pasteurised at a minimum of 60 °C for 3.5 min to ensure microbiological safety. In the UK, the regulatory requirement for LWE is 64 °C for 2.5 min.

They heated egg to 55°C and 60°C for 3.5 minutes, and did not hit these targets.

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    Although, you could always just buy pasteurized eggs, and then you wouldn't have to worry about it. – n_b Dec 30 '18 at 17:35
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    @n_b: That is unsafe advice. See above "[Pasteurisation] resets the clock but does not stop it; cooked food can and will still spoil after 2 hours in the danger zone." – Oddthinking Dec 30 '18 at 18:02
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    The reason why cooked food spoils is because it is exposed to the elements during and after cooking, and bacteria can reach the food through air, contact with unclean surfaces, etc. Pasteurized eggs are done in-shell, so once all the bacteria inside the shell have been killed through the process, there is no way for new bacteria to form in the egg. The egg proteins can still break down and the egg can rot, but harmful bacteria is dead, and safe to eat. – n_b Dec 30 '18 at 18:14
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    @n_b: The answer explains: Pasteurisation is not sterilisation and bacteria leave behind harmful protein toxins. Add to that: egg shells are not impermeable. Pasteurised eggs are safer, but please don't claim that they are always safe and worry-free. – Oddthinking Dec 30 '18 at 23:50
  • @Oddthinking I think you're being a little too safe for safety's sake with that claim. A pasteurized egg is as safe to eat raw as a cooked egg is safe to eat cooked. Yes, if you crack a pasteurized egg on the counter next to your cooked egg and let it linger for a few hours you're at risk from both. The USDA specifically sets that 5 log standard because it makes a pasteurized egg safe to eat raw, and typically USDA standards are conservative because they have a broad population in mind including people with weakened immune systems. – Bryan Krause Jan 2 at 17:52

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