Researchers in Rwanda studied 330 farming families to see if drinking raw milk could make people sick with a bacterial infection called brucellosis. They found that nearly half of families drink raw milk, and about 14% were at risk of getting sick because their milk contained harmful bacteria. Families who let their cows roam freely had much higher rates of contaminated milk compared to those who keep cows in enclosed areas. The study shows that drinking unpasteurized milk, especially from free-roaming cattle, can be dangerous and suggests people need better education about milk safety.

The Quick Take

  • What they studied: Whether drinking raw milk from cows could make farming families sick with a bacterial infection called brucellosis
  • Who participated: 330 farming families in Rwanda - 198 families who keep cows in enclosed areas and 132 families who let their cows roam freely
  • Key finding: About 14% of families were at risk of getting sick because they drank raw milk that contained harmful bacteria, with free-roaming cow families having 70 times higher risk
  • What it means for you: If you drink raw milk, especially from cows that graze freely, you may be at risk for a serious bacterial infection that can cause fever and joint pain

The Research Details

The researchers visited 330 farming families in Rwanda and asked them questions about their milk drinking habits. They also tested milk samples from each farm to see if they contained Brucella bacteria, which can make people very sick. The families were divided into two groups: those who keep their cows in fenced areas (zero grazing) and those who let their cows roam freely (open grazing). The scientists used a special lab test called ELISA to detect the bacteria in milk samples.

This type of study is important because it looks at real-world conditions where people actually live and drink milk. By comparing different farming methods and testing actual milk samples, the researchers could identify which practices put families at the highest risk.

The study included a good number of families (330) and used reliable lab tests to detect bacteria. However, it only looked at one point in time rather than following families over months or years, so we can’t be sure about long-term patterns.

What the Results Show

Nearly half of all families (49%) regularly drank raw, unpasteurized milk. About 14% of families were at high risk because they both drank raw milk AND their farm’s milk tested positive for dangerous bacteria. The difference between farming methods was striking: families with free-roaming cows had contaminated milk 35% of the time, while families with enclosed cows had contaminated milk only 0.5% of the time. Among individual family members, cattle keepers themselves were 50 times more likely to be exposed to the bacteria than other family members.

Out of all 1,589 individual people studied, about 5% were directly exposed to the harmful bacteria through raw milk consumption. The study found that the way cows are raised (free-roaming vs. enclosed) was the biggest factor determining whether milk would be contaminated.

This appears to be one of the first studies to specifically look at brucellosis risk through milk consumption in Rwandan households, so there isn’t much previous research to compare it to. However, the findings align with global research showing that raw milk can carry dangerous bacteria.

The study only looked at families at one point in time, so we don’t know if contamination levels change throughout the year. It also only studied families in Rwanda, so the results might not apply to other countries with different farming practices or climates.

The Bottom Line

Based on this research, families should avoid drinking raw milk, especially if their cows graze freely. Pasteurizing or boiling milk before drinking can kill harmful bacteria. Farmers might consider switching to enclosed grazing systems if possible.

This research is most relevant to people who raise cattle and drink raw milk, particularly in developing countries. People who buy pasteurized milk from stores are already protected from this risk.

The benefits of switching to pasteurized milk or better farming practices would be immediate, as it eliminates the risk of bacterial infection from contaminated milk.

Want to Apply This Research?

  • Track whether you consume raw or pasteurized dairy products daily, noting the source of any raw milk products
  • Switch from raw milk to pasteurized milk or boil raw milk for at least 5 minutes before consuming
  • Log any symptoms like fever, joint pain, or fatigue if you regularly consume raw dairy products, and note the timing relative to consumption

This research is specific to farming practices in Rwanda and may not apply to all regions. If you regularly consume raw milk and experience symptoms like fever or joint pain, consult with a healthcare provider. This information is for educational purposes only and should not replace professional medical advice.