If this is an antigen test, it's probably designed to detect the spike protein since that's the prominent feature on the outside of the viral particle. All this test would do is tell you if it comes into contact with that spike protein or not. There's a threshold to any of these tests regarding the amount of spike protein needed to trigger a positive result, but if this is what I think it is, it's reasonably sensitive. The goal of the test is to catch an infection early and prompt the user to get to the doctor for a PCR test which would be diagnostic. Serology tests aren't diagnostic.
Here's where error comes into play. We have a very sensitive test and a virus that's now ubiquitous in our environment. It's aerosolized, so it's everywhere. We know the viral particle can live on surfaces for extended periods of time. The pear itself could have had actual viral particles on it when you tested it, so when you did the test, it flagged positive.
While that might seem unreasonable, consider that the PCR test is also incredibly sensitive, and easily contaminated. IIRC correctly, it was the President of Tanzania (or perhaps a different African country) who was suspicious about COVID and sent 4 samples to the CDC including swabs from a papaya and from a healthy goat. They came back positive - something easily explained by contamination.
Since you seem interested in trying some more tests, a few questions?
Were the pear and knife washed with soap and water before you cut into the pear to do your test? We'd want to avoid contamination with any surface.
Which specific brand of test are you using?
Instead of testing a weak acid (ie fruit juice), try testing something basic like a bar of soap or a solution of baking soda in water. Most of these tests are pH-sensitive which is why you have to use buffer solutions they often include with the test kit.
It's not contamination. The whole thing is a fraud. Do you know there has never been a complete live virus isolated (defined: purified. Virologists redefined that term to mean a process of poisoning cells) and characterized and proven to be the cause of a specific disease? The PCR method is not diagnostic, it just amplifies any DNA fragments you tell it to look for. Fragments being the key word. It doesn't look for a full genome. If it did, how would it detect the full genetic sequence which is encapsulated in a protein shell and twisted in a double helix?
If this is an antigen test, it's probably designed to detect the spike protein since that's the prominent feature on the outside of the viral particle. All this test would do is tell you if it comes into contact with that spike protein or not. There's a threshold to any of these tests regarding the amount of spike protein needed to trigger a positive result, but if this is what I think it is, it's reasonably sensitive. The goal of the test is to catch an infection early and prompt the user to get to the doctor for a PCR test which would be diagnostic. Serology tests aren't diagnostic.
Here's where error comes into play. We have a very sensitive test and a virus that's now ubiquitous in our environment. It's aerosolized, so it's everywhere. We know the viral particle can live on surfaces for extended periods of time. The pear itself could have had actual viral particles on it when you tested it, so when you did the test, it flagged positive.
While that might seem unreasonable, consider that the PCR test is also incredibly sensitive, and easily contaminated. IIRC correctly, it was the President of Tanzania (or perhaps a different African country) who was suspicious about COVID and sent 4 samples to the CDC including swabs from a papaya and from a healthy goat. They came back positive - something easily explained by contamination.
Since you seem interested in trying some more tests, a few questions?
It's not contamination. The whole thing is a fraud. Do you know there has never been a complete live virus isolated (defined: purified. Virologists redefined that term to mean a process of poisoning cells) and characterized and proven to be the cause of a specific disease? The PCR method is not diagnostic, it just amplifies any DNA fragments you tell it to look for. Fragments being the key word. It doesn't look for a full genome. If it did, how would it detect the full genetic sequence which is encapsulated in a protein shell and twisted in a double helix?