Final answer:
Tests show whether pathogens are present in a potentially time-temperature abused food sample by identifying bacterial growth and specific biochemical reactions. If pathogens are present, the food may be unsafe for consumption due to the risk of rapid bacterial multiplication at unsafe storage temperatures.
Step-by-step explanation:
When checking if food has been time-temperature abused during shipment, a test can show whether or not pathogens were present in the food sample. The presence of pathogens indicates that the food might have been stored at unsafe temperatures allowing for bacterial growth. Tests involve a pre-enrichment culture of the food samples, followed by plating on selective and differential media. These tests can identify the growth of bacteria, where a color change may occur to indicate specific bacterial pathogens. If such growth or biochemical reactions are observed, further tests are conducted to assess the contamination with precision. For a more conclusive determination, additional tests help to confirm the identity of the pathogens, which are based on bacterial phenotypes. In certain cases, laboratory methods can also include serological techniques to identify toxins that can cause symptoms even in the absence of living bacteria. Foods that have been kept at a temperature range between 4 and 60 degrees Celsius (40 and 140 degrees Fahrenheit) for more than two hours are considered time-temperature abused, as this allows rapid multiplication of microorganisms, making the food unsafe. If a particular food item is associated with the occurrence of foodborne disease, it can usually be identified through a case-control study, where those who have fallen ill are compared with those who have not after consuming food from the same source. The onset of symptoms and the results from tests on food samples can be critical in diagnosing a specific foodborne illness.