One of the cooking techniques that I was introduced to in my Harvard Science and Cooking MOOC (Massive Open Online Course) was sous vide. This is a method of cooking whereby vacuum sealed food is cooked in a temperature controlled water bath. It actually works equally well with eggs that have not been vacuum sealed. I thought it would be a perfect way to pasteurize eggs.
As it turns out, eggs go from raw to hard boiled over a relatively small temperature range. At 140° to 143.6° F (60 to 62° C), the egg white will start to coagulate. At 145.4° F (63°C), the white will be set, but the yolk still runny. At 152.6°F (67°C), the yolk becomes like custard, not runny, but not hard either. The yolk will be fully cooked as a hard boiled egg at 170°F (77°C).
Since the egg whites begin to coagulate at around 140°F, one should be able use the sous vide technique to pasteurize them at a temperature below 140°F.
My brother raises chickens and I am incredibly fortunate to have a ready supply of fresh eggs. He had talked about making mayonnaise, but was concerned about the potential health risks of salmonella. I offered to experiment with pasteurizing some eggs for him using the sous vide technique.
Based on some research, it appears that the temperature at which eggs can be pasteurized is 130°F to 135°F.
I filled my polycarbonate container with hot water, and set my immersion circulator at 135°F. Because I was concerned about the eggs being moved around by the water circulation, I placed them in a metal steamer basket, and let them “sous vide” for 90 minutes.
After 90 minutes, I removed the eggs, and placed them in an ice water bath for 20 minutes.
After 20 minutes, I removed the eggs from the ice water bath and placed them on a kitchen towel to dry.
Before placing the pasteurized eggs in an egg carton to be refrigerated, I put a “P” on each one with a permanent marker.
I proudly presented 11 pasteurized eggs to my brother! The reason for 11 as opposed to the dozen that I pasteurized was that I wanted make sure that the white had not begun to coagulate. As can be seen below, the egg was still raw! However, the white was a bit cloudier than the white of an un-pasteurized egg. I had read that pasteurizing eggs does indeed cause the white to be a bit cloudy.
So there you have it – pasteurize eggs with the sous vide method at 135°F for 90 minutes!