When sampling food items how might the expected location of

When sampling food items, how might the expected location of the contamination control how your sample the food items? Give examples to illustrate your point.

Solution

Answer:

Various food hazards can cause expected location of contamination i.e. the majority of food contamination is via cross contamination either via physical, chemical or biological manner. For example, the possible food contamination is by germs located under the hair fingernails when preparing food & during packaging food. The other locations are jewelries, can cause food contamination. Therefore, in order to control food items from cross contamination, it is crucial to control via random food sample analysis for microbial presence. This contamination can be avoided by wearing hair- nets or hats to stop falling of hazardous material into the food material when it is under preparation or packaging. Regular cleaning and hygiene protocols must be performed to control the contamination. The sampling is performed to locate the exact presence of contamination using \"biological colifrom indicator methods\" as described below.

For example, “a food sample with 1,000,000 bacteria” treated with agent X in 30 seconds ---> bacterial count reduced to 10 i.e. the agent-X that kills 99.999% of bacterial cells in the food sample

Positive test for coliforms in a food sample is considered more serious. A limitation of coliform bacteria as indicators is that some of other microorganisms are more persistent than coliform but more difficult to inactive because of presence coliform bacteria may still contain viruses, which difficult to inactivate

The main purpose of using eosin-methylene blue agar medium is because it has specific toxic nature to Gram positive and useful to detect coliform Gram- negative bacteria therefore it is selective and differential medium for the identification of Gram- negative bacteria. For example, prokaryotes such as Escherichia coli often form black to metallic green colonies on EMB (eosin-methylene blue agar medium). These eosin & methylene blue are going to be useful mainly for isolation, differentiation of coliforms in water & food and fecal coliforms in water & food samples