Category: Bacteriology

While a major taxonomic review in 2020 reclassified much of the genus, the core characteristics of these lactic acid producers remain consistent: are Lactobacillus Gram-positive bacteria? Yes, the overwhelming majority are, a feature central to their classification and vital role in fermented foods and human health.

Introduced in 1904 by Dutch professor Christiaan Eijkman, the Eijkman test was a pioneering method designed to detect harmful fecal contamination in water supplies. This differential test, which relies on temperature-sensitive bacterial growth, provided a significant advancement over earlier, less specific methods for evaluating water safety.

According to recent studies, certain species of *Bacillus* are indeed recognized as beneficial probiotics, a significant departure from traditional non-spore-forming strains like *Lactobacillus*. But is a Bacillus a probiotic, and how do they differ from other strains?

The ability to ferment specific carbohydrates is a key characteristic used to classify and differentiate bacteria. Recognizing what does a positive carbohydrate fermentation test look like is a fundamental skill for microbiology students and laboratory technicians, relying on clear visual cues after incubation.

Escherichia coli (E. coli) bacteria can survive and thrive in a surprisingly wide range of temperatures, from freezing to body temperature. While most strains are harmless, pathogenic types like E. coli O157:H7 can cause severe illness, making it critical to understand how temperature affects their survival and growth.