You might want to skip the fancy cheese plate at your next party, especially if you’re pregnant. Whole Foods recently recalled Vulto cheese made from raw milk after a deadly outbreak of Listeria monocytogenes. One victim is a newborn baby.
There is also a massive ongoing cheese recall because a sample of pasteurized Colby tested positive for Listeria in Tennessee. The recall includes hundreds of deli-counter cheese horns and pre-packaged cheese products sold by Sargento, Guggisberg, Sara Lee, Meijer, and more.
The recalls include pasteurized hard cheeses like Cheddar and Gouda, which are generally considered safe to eat during pregnancy. However, experts may be underestimating the risk. In one recent study, pregnant monkeys in their first trimester who ate Listeria had no symptoms, but miscarried almost immediately.
Pregnant women usually have “silent” infections, with no symptoms other than an unexplained miscarriage, premature birth, or stillbirth. Babies who survive Listeria in the womb can be born with brain damage.
The problem is that Listeria is widespread on dairy farms and it can cause udder infections (mastitis) in cows. Infected animals can look healthy and still produce milk that is contaminated with Listeria. Studies estimate that 16% of dairy cows are infected and 2% of raw milk contains Listeria worldwide. Raw milk can also contain Salmonella, E. coil, or Campylobacter without looking or smelling any different.
The other problem is that Listeria can grow in refrigerator temperatures. It thrives in cold, dark, wet nooks and crannies on food processing equipment that are difficult to clean. Once established in a facility, Listeria is nearly impossible to eradicate, and pasteurization is no guarantee of cleanliness. Too much bacteria in the milk can make pasteurization ineffective. Dirty milking equipment can spread infections throughout the herd.
Outbreaks of food poisoning resulted in the FDA banning interstate sales of raw milk in 1987, with the exception of raw milk cheeses aged for 60 days. Even so, 31 states currently allow direct sales of raw milk at farms or stores.
Pasteurized milk is not sterilized, but it is a lot safer to drink and lasts longer. Milk is heated at 161ºF for 15 seconds to kill spoilage bacteria and microorganisms that can transmit diseases to humans. Pasteurization also destroys 10-30% of heat-sensitive nutrients like vitamin C and thiamine, as well as lipase and free fatty acids.
The big disadvantage is taste. Pasteurization destroys some important nutrients and flavor-producing enzymes. There is no way to recover the flavor, which is why raw milk cheeses are considered far superior to pasteurized cheeses. In France, where raw milk cheeses make up 18% of total production, pasteurized cheese is considered almost sacrilege.
Pasteurized cheese can still be high-quality, but there is no way to replace its distinctive “plastic” flavor with the grassy, nutty, tangy, sweet, creamy taste of raw milk cheese. The signature taste and texture of raw milk is why consumers are willing to risk their health — but no amount is safe during pregnancy.