Which of the following is a common way cross contamination can occur in a microbiology laboratory?

• A. Using the same pipette for different samples without sterilization
• B. Storing samples at the correct temperature
• C. Labeling all samples clearly
• D. Wearing gloves while handling samples

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. Identify common laboratory practices that can lead to cross contamination, such as reusing equipment without proper sterilization, improper handling of samples, or inadequate personal protective equipment.
3. Evaluate each option given in the problem to determine if it could cause cross contamination. For example, using the same pipette for different samples without sterilization can transfer microbes between samples.
4. Recognize that practices like storing samples at the correct temperature, labeling samples clearly, and wearing gloves are preventive measures that help avoid contamination rather than cause it.
5. Conclude that the most common way cross contamination occurs among the options is by using the same pipette for different samples without sterilization, as this directly transfers microorganisms between samples.