From: billd@informix.com (William Daul)
Newsgroups: rec.food.cooking
Subject: Re: Safe Egg Yolks
Date: 15 Aug 92 07:16:19 GMT
Organization: Informix Software, Inc.


How safe should you be with eggs today?
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From June 1991 SUNSET Magazine (copied without permission)

The culprit is salmonella. It calls for new ways of dealing with eggs

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SAFE: 140 degrees for 3 1/2 minutes
Pan-poached yolk is still semiliquid
minimum salmonella-safe temperature.
=====================================

One of nature's most effectively packaged foods, the egg, has taken a
lot of hard cracks of late. It has been pinpointed as the source of
outbreaks of salmonella poisoning and has been the subject of much
discussion in the press.

What is salmonella?  How does it get into foods? Must we avoid eggs to
avoid it? Are there ways to safeguard foods?

In a months-long research project, both in our kitchens and in an
independent research laboratory we have crackled and cooked a lot of
eggs to come up with some answers to the big question: can you still
use eggs raw or lightly cooked in your favorite dishes?

What is salmonella?

Very common and widely present, salmonella bacteria (of which there are
numerous strains) can cause food poisoning and gastrointestinal
distress. Under certain conditions-including a combination of time and
temperature-salmonella can thrive in many foods, most typically those
that contain protein-not only eggs but that contain protein-not only
eggs but also others such as fish, meat, and poultry.  The bacteria can
also multiply on less obvious foods like fruits and vegetables if they
come in contact with the bacteria and are held under conditions that
are sufficiently warm and moist.

==========================================
SAFE: center of meringue is 140 degrees
Golden meringue on lemon pie is baked for
25 to 30 minutes to reach safe temperature
==========================================

Cooking to sufficient heat levels destroys salmonella. Acid is another
way to control salmonella; see details on page 88.  If salmonella-free
solid meat, like beef steak or chicken breast, comes in contact with
the bacteria, only the surface will be contaminated. When cooked enough
to be browned and flavorful, these foods will be much hotter on the
surface than needed to kill salmonella.

==========================================
UNSAFE:  eggs stored at room temperature.
==========================================

==========================================
SAFE: acid with uncooked egg white
      Egg white with lemon juice makes a safe but thick
      mayonnaise (acid in lemon kills salmonella in 48 hours)
==========================================

Until the last few years, home cooks had little cause to worry about
the safety of well-handled eggs. But serious outbreaks of salmonella
illness in the Eastern states were traced to eggs. (So far, no
comparable incidents have occurred in the West.)

How does salmonella get into eggs?  How do you deal with it?

How eggs become contaminated is at the center of the widespread alarm.
Some salmonella found in eggs got there before the shell formed; the
current concern is that this appears to be happening more often in some
areas of the country.

Yolks are most susceptible to salmonella growth. According to current
research, egg whites have natural defenses against salmonella; they're
designed to protect the nutrient-rich yolk in which bacteria, given
opportunity, can thrive. Even though egg less vulnerable, however,
contamination is still a possibility

Avian (poultry and egg) scientists are divided how to deal with eggs.
Some recommend that eggs be totally cooked or that pasteurized eggs
(not readily available to consumers) be used. Others feel that
properly handled eggs can be enjoyed in recipes even without cooking.

Bear in mind that raw and lightly cooked eggs have never been advised
for certain people: young children; the aged; and individuals taking
medications that alter the immune system, such as treatments for
cancer.

Unfortunately, unless your kitchen is equipped with laboratory tools
(rare in homes) needed to spot salmonella, you can't tell if it is
present.

The basic rule of food safety:  proceed as if a problem exists

The following procedures-recommended by food scientists, lab-tested for
Sunset, and double-checked in our kitchens-will give trouble-free
results. The tools and techniques are simple: they have to do with
cleanliness, temperature, time, and acidity. We have used the
procedures with raw and lightly cooked eggs. You can also use them with
your own recipes.

First, choose and handle eggs with care.  Be sure the eggs you buy are
fresh (most cartons are dated) and have always been refrigerated below
at least 50 degrees (this is difficult to confirm). Then keep the eggs
in the refrigerator until you use them.  Salmonella grow and quickly
reach danger levels within hours when the temperature is 60 degrees or
warmer.

If you use eggs raw or lightly cooked, observe these precautions:

1. Use only eggs that have been refrigerated at all times. Do not let
   eggs stand at room temperature more than a total of 2 hours at 
   any time before consuming (Some authorities feel this is 
   overcautious and are comfortable with a total of 4 hours).

2. Serve any foods with lightly cooked eggs immediately, or chilled at
   once to serve cold. Do not let these chilled foods stand at room
   temperature long enough to warmup.

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SAFE:  scalding milk on raw eggs
For uncooked ice cream, scalding milk
heats raw eggs to safe temperature
=====================================

3. Wash hands with soap and water. Do this before handling foods and
   between foods that can cross-contaminate, like raw chicken or fish,
   then an egg.

4. Keep work areas clean. Wash with hot soapy water, then rinse when
   you change foods' like meats to salad greens-or eggs.  To avoid
   cross-contamination, keep tools and equipment clean.

5. If using whipped raw egg whites, be sure to keep foods containing
   them chilled at all times. These include fluffy desserts 
   like mousses, souffles, and bavarians. (When we tried making 
   meringues with hot sugar syrups instead of sugar, they did not 
   reach salmonella-killing temperature without becoming too sweet.)

Two salmonella killers: heat and acid

To enjoy eggs soft or lightly cooked, gentle heat is important. Two
heat-killing methods work: either cook food to 140 degrees and hold at
that temperature for 3 1/2 minutes, or cook to 160 degrees (no
holding time required).

For some mixtures, like mayonnaise or dressing for a Caesar salad, that
rely on raw egg to form an emulsion or give the dressing a clinging
quality, we have found that egg white works as effectively as whole
egg. When using raw egg whites, a few steps taken to lower their acid
level to 3.5 will ensure they're safe to consume.

To be sure foods are hot enough or acidic enough to kill salmonella,
you need some simple measuring tools.

Temperature.  An accurate quick-read thermometer is indispensable for
determining the internal temperature (in the center) of cooked foods.
Occasionally verify the thermometer's accuracy by dipping in
boiling water (212 degrees at sea level, 208.4 degrees at 2,000 feet,
203 degrees at 5,000 feet).  To avoid any possible contamination, dip
the thermometer in boiling water before using it to test eggs. Also,
the thermometer's ability to register rapidly (important with
quick-cooking eggs) is enhanced if you dip it first in hot water.

==========================================
SAFE:  custard coats spoon
       Stirred custard is past a very safe
       160 degrees when thick enough to coat spoon
==========================================

Acid.  To measure acidity, buy pH indicator strips at a scientific
supply store. A package of 100 usually costs less than $10. Choose
strips that indicate pH between 3 and 6 (the lower the number, the
greater the acidity).

To use, moisten a strip with the food, then check the color the paper
turns against color guides on the package. When pH measures 3.5 or
lower, the food's acid level is adequate, under refrigeration, to stop
growth of salmonella and then kill it within 48 hours.

Soft-cooked Eggs

Once you've seen how eggs look at a salmonella-safe temperature, you
can judge the internal temperature fairly accurately by eye. Serve
softly cooked at once; otherwise, yolks continue to firm.

Poached.  Put large eggs (at refrigerator temperature) into individual
poaching cups. Cook, covered, over simmering water until 140 degrees
in the center of the yolks, then hold at that temperature (over water
but off heat) for 3 1/2 minutes. Yolks will still be semi-liquid in
center. Eggs cooked just to 160  degrees at the center are still moist
but not liquid.

In the shell. Put up to 6 large eggs (at refrigerator temperature) in a
2- to 3- quart pan; add cold water to cover them by about 1 inch. Bring
water to 200 degrees over high heat; remove from heat and let stand 1
minute. Remove 1 egg and plunge a thermometer into center of yolk; the
temperature should be 140 degrees (if not, check after 1 more
minute). Once yolks are 140 degrees in center, let remaining eggs stand
in water for 3 1/2 minutes longer; yolks will be semi-liquid.

To bring eggs to 160 degrees in the center, leave them in water 7
minutes after removing from heat.

Once you've achieved the results you want, you can duplicate them with
the same amount of water and 1 to 6 eggs, and skip the thermometer.

Fried.  Break refrigerated eggs into frying pan and cook over low to
medium heat, turning once; when yolks begin to firm all around but are
still semi-liquid in center, the temperature will be 140 degrees (as
shown for poached egg, page 86); keep warm in pan on lowest heat for 3
1/2 minutes. Or continue to cook to doneness desired.

Omeletes.  Omeletes (not the puffy kind) that are still shiny and
moist-looking on the surface will be, when folded or rolled over, more
than 160 degrees in the center.

Scrambled.   Test with your thermometer to make sure they are cooked to
140 degrees and held at that temperature for 3 1/2 minutes; or cook to
a firmer 160.

Ice Cream

Ice cream is often made by beating together milk, sugar, and flavoring
with uncooked eggs. A simple precaution that does not alter the quality
of the finished product is to heat the milk and sugar to 200 degrees,
then whisk this mixture into a deep metal bowl with eggs (at least 1
cup milk and 1/4 cup sugar for each 3 refrigerator temperature large
eggs). Check temperature; if 160 degrees, beat no further. If between
140 degrees and 160 degrees, set bowl in a container of 150 degrees
water and stir for 3 1/2 minutes. Chill mixture, add flavoring, and
continue as your recipe directs.

Stirred and Baked Custards

By the time either of these mixtures is hot enough to thicken, it
exceeds 160 degrees (see photograph on page 88). Serve hot or warm; or
cover, chill, and serve cold.

Hollandaise and Bearnaise Sauces

You can make cooked or uncooked versions of either sauce
salmonella-proof by heating butter to a specific temperature.

For 1 large egg or 3 large egg yolks (all refrigerator temperature) and
1 tablespoon lemon juice or vinegar (add more later, to taste), you
need 1 cup (1/2 lb.) buffer or margarine heated to 220 degrees.

Either whisk hot butter in a rapid steady stream into eggs over hot
water or very low heat, or pour into whirling eggs in a blender or food
processor. If the temperaure of the sauce is not at least 160 degrees
when all the butter is added, set container in a bowl of 150 degrees
water and stir or whisk for 3 1/2 minutes. Remove from heat, mix in
seasonings, and serve.

Zabaglione

Start with at least 4 large egg yolks plus 1/2 cup wine or fruit juice,
and sugar to taste.  By the time you have whisked the mixture over
direct heat or simmering water until it is thick enough to mound
slightly, it is usually at least 160 degrees. If not, continue to whisk
in pan in a bowl of 150 degrees water for 3 1/2 minutes.

Soft Meringue for Pie

Sugar in whipped egg whites makes meringues even less hospitable to
salmonella but does not destroy it. To be salmonella-proof, the
meringue must be baked on the pie longer and at a lower temperature
than typical, so the heat penetrates. Chill meringue pies until
served.

For an 8- to 9-inch pie, whip 4 large egg whites (at refrigerator
temperature) with 1/2 teaspoon cream of tartar on high speed, until
frothy; gradually beat in 1/4 cup sugar, whipping until whites hold
soft peaks.  Pour hot cooked pie filling (such as chocolate or lemon)
into baked pie shell. At once swirl meringue over filling, sealing to
pie shell. Bake in a 325 degrees oven until meringue is evenly
browned and temperature in meringue center is 140 degrees or above, 25
to 30 minutes. Chill (warm filling also needs to firm) and serve cold.

Acidified Egg White

Mix 1 large egg white with 2 tablespoons lemon juice. Check pH; it
should be 3.5.  If not, add more lemon juice, 1 tablespoon at a time,
checking with each addition until pH is 3.5. Cover airtight and
refrigerate at least 48 hours or up to 4 days (on longer standing, the
egg begins to solidify); use as directed, following.

Acidified Egg White Mayonnaise

Put 1 acidified egg white (directions precede) in a blender, food
processor, or deep bowl of an electric mixer. Add 2 tablespoons water
and 2 teaspoons Dijon mustard. Whirling or beating at high speed, add
1 cup salad oil or olive oil in a slow stream until mixture starts to
thicken, then add faster, incorporating smoothly.  Add more lemon juice
and salt to taste.  Serve or cover and chill up to 4 days.  Makes about
11/2 cups.

Per tablespoon: 98 cal.; 0.2 g protein; 11 g fat,
0.2 g carbo.; 18 mg sodium; 0 mg chol.

Acidified Caesar Salad Dressing

In a blender, food processor, or deep bowl of an electric mixer, whirl
or beat 1 acidified egg white (directions precede) with 2 tablespoons
lemon juice, 1/2 cup olive oil or salad oil, 2 teaspoons
Worcestershire, and 1/2 teaspoon freshly ground pepper. Finely chop 6
to 8 drained canned anchovy fillets and add to dressing. Makes about
1/4 cup.  In a large salad bowl, put 8 to 9 cups rinsed and crisped
bite-size pieces romaine lettuce. Pour dressing over salad; as you
mix, sprinkle greens with 2 to 4 tablespoons freshly grated parmesan
cheese.  Makes 7 or 8 servings.

Per serving: 80 cal.; 2.3 g protein; 7.2 g fat; 2.1 g
carbo.; 137 mg sodium; 1.7 mg chol.

====================================================
====================================================
Testing for egg safety

To determine how to cook eggs to salmonella-safe temperatures, or to
acidify egg whites to cat uncooked, Sunset food editors did extensive
research over many months, converted what they learned to workable
kitchen procedures, and then had the results checked by leading
authorities and an independent food laboratory.

In our kitchens, we could evaluate processes that used heat to kill
salmonella. Sunset food editor Karyn Lipman (at right) cooked hundreds
of eggs by a number of methods, each time checking the internal
temperature of the egg or food containing eggs.

Thermometers were frequently checked for accuracy; to do the same, see
temperature section, page 88.

For whole eggs, she found the texture of the just-cooked yolk to be an
accurate way to gauge its internal temperature, even without a
thermometer.

Enlisting the help of a laboratory

To test how effectively acid killed salmonella, we needed scientific
help.  Authorities assured us that salmonella bacteria don't grow in an
acid medium, and that the acid also probably killed them under
controlled temperatures.  But they did not know whether this was true
when acid was at low enough levels to be palatable.

We focused on testing ratios of lemon juice and egg white that would
work well to make the flavorful mayonnaise and the Caesar dressing
(above). Then we contracted with an independent laboratory to run tests
on egg white and lemon juice mixtures with these proportions.

In the lab, some mixtures were left salmonella-free; the rest were
inoculated with varying amounts (some very large) of the bacteria. Also
tested were egg whites without lemon juice, plain and
salmonella-inoculated. Mixtures were refrigerated. Samples taken at 1,
4, 24, and 48 hours were cultured. Salmonella in the acid mixtures
began to decline significantly and were less than detectable after 48
hours.

At home, to be assured that you have a safe amount of acid, you can use
testing paper (page 88).

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 William Daul             Advanced Support      INFORMIX SOFTWARE INC.
 4100 Bohannon Dr.        (415) 926-6488 - wk
 Menlo Park, CA. 94025    uunet!infmx!billd  or  billd@informix.com