Which of the following could cause cross contamination in a microbiology laboratory?

• A. Unsterilized equipment between samples
• B. Labeling all samples clearly
• C. Using separate gloves for each sample
• D. Disinfecting work surfaces before and after use

Answer: (A)

Verified step by step guidance

1. Understand the concept of cross contamination: it occurs when microorganisms are unintentionally transferred from one sample or surface to another, potentially leading to inaccurate results or contamination of cultures.
2. Evaluate each option by considering whether it introduces a risk of transferring microbes between samples or surfaces.
3. Recognize that 'Unsterilized equipment between samples' can carry microbes from one sample to another, directly causing cross contamination.
4. Note that 'Labeling all samples clearly' is a good laboratory practice but does not cause cross contamination because it does not involve physical transfer of microbes.
5. Understand that 'Using separate gloves for each sample' and 'Disinfecting work surfaces before and after use' are preventive measures that reduce the risk of cross contamination.