Listeria in Cantaloupe

Today, the news is all about cantaloupe contaminated with listeria.

Update:

Since this post was originally made, there have been several news reports.  Here are links to just a few:

• US Listeria cases likely to rise through October
• Experts fear listeria may be moving into produce
• Listeria in cantaloupe: What you need to know

How Do I Know If There is Listeria in Cantaloupe?

You can’t actually tell if food is contaminated by looking at it.  In both the US and Canada, there is a government website that lists all recent food recalls.  Make sure that you are not eating anything on these lists.

• FDA Food Recalls
• Canadian Food Inspection Agency Food Recalls

What Should You Do If You Have Food Recalled Because of Listeria Contamination?

Don’t take any chances.  Throw out food that has been recalled because of Listeria contamination.

If you have eaten a contaminated product and do not have any symptoms, don’t worry. You are probably okay.  If you become ill however, you should contact your health care provider as soon as possible.  Be sure to mention your possible exposure.

What is Listeria?

Listeria monocytogenes (or just Listeria) is a type of bacteria commonly found in nature.  Named after the English scientist Joseph Lister, it can cause a serious, but rare disease called listeriosis.

Who is at Risk?

Many people and animals may be carriers of Listeria, but few will actually develop listeriosis.  The people most at risk of developing listeriosis are pregnant women, the elderly, or anybody else with a weakened immune system.

Pregnant women are about 20 times more likely to develop the disease than other healthy adults.  There is a risk of miscarriage, stillbirth or very ill baby.

Symptoms:

Mild cases of food poisoning cause by Listeriosis usually begins one day after eating the contaminated food. More serious forms of the disease can take longer to incubate, up to 90 days after exposure.

People who do develop the disease will notice the sudden onset of symptoms including:

• Vomiting
• Nausea
• Cramps
• Diarrhea
• Severe Headache
• Constipation
• Persistent Fever

In very serious cases, Listeria may be followed brain infections (meningitis encephalitis) or blood poisoning (septicemia).  Either of these can cause death.

Treatment:

Listeriosis can be treated antibotics, but early diagnosis is critical.
There is no vaccine for Listeriosis.

How Does Food Get Contaminated With Listeriosis?

Similar to E. coli contamination, plants and vegetables can become contaminated with Listeria from the soil, water and manure-based fertilizers.

Preventing Foodborne Illnesses (including Listeria):

Other posts have talked about ways to prevent foodborne illnesses.  Basically, you want to follow four rules:

1. Sanitize:
   • Before handling foods, wash your hands with soap for at least 20 seconds.
   • Ensure counter-tops and utensils are clean and sanitized.
   • Wash raw fruits and vegetables under clean running water.
2. Chill:
   • To slow bacteria growth, keep cold food below 4°C (40°F).
   • Freezing (below -18°C or 0°F) food can stop bacteria growth completely but it won’t kill the bacteria.  Only proper cooking can kill the bacteria.
3. Separate:
   • Don’t cross contaminate!  Make sure the juices from raw meat do not touch any other foods.
   • If plates or utensils are used for raw meats, they should not be used with cooked or ready to eat foods.
4. Cook:
   • Cooking meat to a safe internal temperature destroys e. coli bacteria.
   • The safe internal temperature depends on what you are cooking.  Refer to this chart.
   • You cannot judge the temperature by colour, look or feel!
   • Use a meat thermometer to check the internal temperature of your food.

If you found this post useful, or if you have any thoughts on food contamination, please leave a comment.

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Other sources: Health Canada – Listeria and Food Safety