Germy Meat Gives Scientists Surprising New Clues About Prehistoric Cuisine

What was the culinary experience like for our prehistoric forebears?

No one knows for sure. But a provocative new study suggests that any meat our distant ancestors scavenged would have been teeming with harmful bacteria.

What's more, the study suggests, early hominins would have had trouble avoiding food-borne illness unless they cooked the carrion or opted to consume bone marrow rather than flesh.

"Some would argue the archaeological record indicates that meat was scavenged before the earliest accepted dates of controlled fire-use, but our research suggests that cooking might be more ancient," Alex Smith, the study's lead author and a researcher in Harvard University's department of human evolutionary biology, told The Huffington Post in an email.

Most scientists agree that cooking dates back about 1.9 million years.

To take a closer look at the possible link between scavenging and cooking, the researchers measured the growth of bacteria on raw boar meat and bone marrow over a 24-hour period and how effectively roasting the meat eliminated the bacteria.

What did the researchers find?

The number of bacteria on the raw meat spiked to potentially dangerous levels within 24 hours, but roasting the meat over hot coals killed most of the bacteria. As for the bone marrow, fewer bacteria grew on it than on the meat, which suggests that it would have been somewhat safer to eat than meat.

"The accumulation of bacteria on exposed tissue and the reduction of this bacterial load via cooking were not surprising findings," Smith said in the email. "What is surprising is that two processes known to influence the biological value of food (bacterial decomposition and cooking) are often absent from discussions about hominin scavenging ecology... We hope this research brings the importance of cooking and its effects to discussions on early hominin carnivory."

A paper describing the research was published in the July 2015 edition of the Journal of Human Evolution.