Listeria in hard-boiled eggs? How come?

A company called Michael Foods has recalled more than one million hard-boiled eggs because of possible contamination with Listeria monocytogenes.  These especially nasty bacteria grow happily at refrigerator temperatures.

Michael Foods packaged the eggs in buckets of brine at a facility in Wakefield, Nebraska.  Investigators suspect a room in the packaging plant as the most likely source of contamination.  Listeria do tend to lurk in wet crevices of packing plants.

The company’s recall notice says:

None of the eggs were sold directly by Michael Foods to retailers or consumers. However, food distributors and manufacturers who purchased the eggs could have used them in products that were sold to retail outlets or used in foodservice settings.

Think: commercially prepared egg salad sandwiches and potato salads.

If you can’t quite get how a million hard-cooked eggs could be exposed to Listeria, you have plenty of company, mine included.

Hard-boiled eggs are boiled.  They are sterile.  What could have happened?

I went to the Web to find out how eggs are processed for commercial use, and discovered the Sanovo Group.   This company produces machines that wash and peel hard-boiled eggs (check the video).

The company’s SB 20000 Egg Boiler, for example:

automatically boils, cools and peels up to 20,000 eggs/hour. It can handle both brown and white eggs [Huh?  Why would anyone expect a difference?]….The SB 20000 Egg Boiler centres the yolk on stainless steel rollers, improving the egg quality and yield. A uniform boiling of the eggs is obtained by the built-in conveyor working with up to 18 minutes boiling time.

The boiled eggs are cooled for 23 minutes in the SC 20000 Egg Cooler, improving the peeling of the eggs. Ice water is injected in the centre of the cooling drum for optimal cooling transmission to the egg.

The SP 20000 Egg Peeler gently cracks the eggshells. Using the hygienic and no-scratch peeling technique. The complete system is easily cleaned for optimal hygiene.

The contamination must have occurred after the eggs were peeled or while they were in the buckets.

To me, the mere thought of peeled, hard-cooked eggs sitting in pails of cold, Listeria-friendly salt water for who knows how long be should make anyone run for the nearest testing kit.

These egg recalls are a perfect example of the hazards of industrial-scale food production.

Support your local egg farmer and peel your own eggs!