After spending approximately 40 weeks inside the womb, the average newborn weighs 7 1/2 pounds. Most babies weigh between 5 1/2 and 10 pounds. The average length of a newborn is 20 inches (50 centimeters), with a range of 18 to 22 inches. The average head circumference (the distance around the head) is 14 inches (35 centimeters).
Lactobacillus and Bifidobacterium are the most common probiotic bacteria. The Lactobacillus genus has 18 different bacteria strains, while the Bifidobacterium genus consists of eight strains.
Probiotics are microorganisms â typically bacteria â that are thought to be beneficial to digestion and in preventing certain illnesses. Sometimes called good or friendly bacteria, probiotics are available in supplement form and are added to foods such as yogurt.Traveling through the human digestive system, however, can be challenging for bacteria, especially when it comes to surviving the powerful acid in the stomach.ccording to U.K. food microbiologist Glenn Gibson, quoted in a 2008 story in The Sunday Times, only highly resistant bacteria such as lactobacillus and bifidobacteria can survive stomach acid. Other types of bacteria, including many probiotics, are likely to be destroyed by stomach acid.