YOU ASKED: Why do we refrigerate our eggs?

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You Asked: Is there really a “dirty secret” about almonds?

Screen Shot 2015-03-30 at 11.35.07 AMAnytime you see an article that starts off with the heading “The Truth About….,” it’s a pretty safe bet that you will not get the truth. And so it is with an article circulating about almonds. “The Truth About Almonds: Almost No One Knows This Dirty Secret.” What is the “dirty secret?” That the almonds are treated with the fumigant propylene oxide to prevent contamination by salmonella bacteria. Salmonella infection is not pleasant to say the least. But people mostly associate it with contaminated eggs, not almonds. Where do the bacteria come from? Mostly fecal matter. Easy to see how eggs can be contaminated as they are laid. But almonds? Birds and insects can spread the bacterium after contacting fecal matter, but exposure may also be indirect through contaminated irrigation water. Salmonella bacteria can survive a long time even in dry conditions and dry heat treatment is not very effective at killing them. But fumigation with propylene oxide is. The nuts are placed in a chamber with liquid propylene oxide and the pressure is then reduced to allow quick evaporation of the liquid. The vapour destroys bacteria very effectively, preventing the possibility of food poisoning. There is no secret here. And nothing dirty is going on.

So what is the alarm all about? That propylene oxide is an animal carcinogen. That does not mean it is known to cause cancer in humans. And even if a substance is a human carcinogen, dosage still matters. While “carcinogen” is a frightening term, all it means is that the substance is capable of causing cancer in some animal at some dose. But there is a threshold effect. In rats no cancer can be found at any dose less than nine milligrams per kilogram of body weight, which has been established as the No Observed Adverse Effect Level (NOAEL). In other words at that dosage there is absolutely no problem detected.

Canada does not grow almonds so there has not been an application to allow the use of propylene oxide. This is not the same as it having been banned, as some alarmists claim. However, since Canada does import almonds that may have been treated with the chemical, the Pest Management Regulatory Agency has looked at the animal data and concluded that the maximum permissible residue is 300 parts per million. That is way below the NOAEL. And how much are almond eaters actually exposed to? The only way to know is to test for residues. That’s why the Canadian Food Inspection Agency tested over a thousand samples of spices, herbs, cocoa powder and nuts, including almonds. Guess what they found? No residue at all! So there is no reason to be concerned about propylene oxide in almonds because it isn’t there. And that is the truth.

Joe Schwarcz

You Asked: Are pasteurized cheeses safe to consume?

Screen Shot 2014-12-26 at 2.45.34 PMWhile selling raw milk in Canada is illegal, the sale of cheese made from unpasteurized milk is allowed as long as the cheese has been aged at 2 degrees C or above for at least 60 days. Studies have shown that if this procedure is followed, the added salt and acids produced by the added bacterial cultures prevent harmful listeria, salmonella and E. coli bacteria from growing. The risk that remains is very small but not zero. It is the soft and semi-soft cheeses that have a better chance of retaining problematic bacteria and this is where the issue gets more complicated because these cheeses reach their peak ripening point at 20-30 days. Quebec, contrary to the rest of Canada and most U.S. states, now allows soft cheeses like Brie and Camembert made from unpasteurized milk to be sold without the 60 day requirement, citing the European example where these cheeses have always been made from raw milk with no problem.

Still, to be on the safe side, it would be prudent to avoid raw milk cheeses during pregnancy, infancy or by people with compromised immune systems. But identification of cheeses made from unpasteurized milk is difficult since labeling is not required. Many artisan cheeses will voluntarily reveal that they are made from raw milk, hoping to capture the attention of foodies who believe that the taste is superior. Whether that is true is arguable. It is interesting that people who clamor for the labeling of any food that may somehow be linked to genetic modification are silent about asking for the labeling of raw milk cheeses.

 

Dr. Joe Schwarcz

You Asked: Are pasteurized cheeses safe to consume?

pasteurized cheeseWhile selling raw milk in Canada is illegal, the sale of cheese made from unpasteurized milk is allowed as long as the cheese has been aged at 2 degrees C or above for at least 60 days. Studies have shown that if this procedure is followed, the added salt and acids produced by the added bacterial cultures prevent harmful listeria, salmonella and E. coli bacteria from growing. The risk that remains is very small but not zero. It is the soft and semi-soft cheeses that have a better chance of retaining problematic bacteria and this is where the issue gets more complicated because these cheeses reach their peak ripening point at 20-30 days. Quebec, contrary to the rest of Canada and most U.S. states, now allows soft cheeses like Brie and Camembert made from unpasteurized milk to be sold without the 60 day requirement, citing the European example where these cheeses have always been made from raw milk with no problem.

Still, to be on the safe side, it would be prudent to avoid raw milk cheeses during pregnancy, infancy or by people with compromised immune systems. But identification of cheeses made from unpasteurized milk is difficult since labeling is not required. Many artisan cheeses will voluntarily reveal that they are made from raw milk, hoping to capture the attention of foodies who believe that the taste is superior. Whether that is true is arguable. It is interesting that people who clamor for the labeling of any food that may somehow be linked to genetic modification are silent about asking for the labeling of raw milk cheeses.

Joe Schwarcz

 

Chicken requires careful handling

chickenEstimates are that some 55 million people in Canada and the U.S become ill every year from eating tainted food with more deaths attributed poultry than any other food. That of course is partly due to poultry being the most popular meat, with consumption being about 83 pounds per capita per year. Tests by Consumers Union show that virtually all chicken is contaminated by bacteria. That by itself is no great surprise. Chickens’ guts, like those of humans, are filled with all sorts of bacteria and cause no harm to the bird. But when chickens are slaughtered the bacteria can transfer to the meat. Contamination also occurs when chickens tromp through the feces that collect in their cramped quarters. Some of these bacteria have developed a resistance to antibiotics because these drugs are fed to poultry in small doses to speed up weight gain. This practice kills off susceptible bacteria and allows those with natural resistance to thrive. The use of antibiotics in animal feed needs to be curbed because tests have already shown the widespread presence of antibiotic resistant salmonella, campylobacter, E. coli, enterococcus, klebsiella pneumonia and staphylococcus aureus on at least half of chicken samples. Some salmonella strains are especially virulent. All these bacteria can spread to people and can cause infections that defy treatment. About 80% of all antibiotics produced are used in animals, a recipe for disaster.

Bacterial contamination does not mean that chicken should be shunned, but proper handling and cooking is critical. Assume that all raw chicken is contaminated. Tests show that when it comes to contamination, whether the bird is labeled organic, antibiotic-free, natural, free range or no hormones added makes no difference. “Natural” means nothing and no chickens are given hormones. From the moment you pick up a package of chicken in the store, there is risk. Just touching the plastic wrap and then touching your mouth could make you sick, although this is not likely. At the checkout counter, put chicken in a plastic bag to prevent cross-contamination. Do not wash the chicken before cooking, splashing water can spread the bacteria as far as three feet from the sink. Remember that bacteria can survive on some surfaces for days so if you handle the chicken and touch the water tap, you’ve left some bacteria there. Hand washing after handling chicken is critical and don’t use the same cutting board that was used for chicken for chopping anything else without scrupulous cleaning it first. Better to have a separate cutting board. When it comes to cooking, all bacteria are killed if the internal temperature reaches 75 Celsius which you can only be sure of with a meat thermometer. These are important precautions unless you fancy a bout of nausea, vomiting, diarrhea, stomach cramps and fever. Or worse.

 

Joe Schwarcz

Raw Eggs in Eggnog: Should we be worried?

Should we be worried about raw eggs in Eggnog?

Raw Eggs

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