An investigator attempting to replicate Pasteur's swan-necked flask experiment has boiled a hay infusion for 1 hour. However, she observes growth in the flask after 1 day (even when undisturbed). What is the likely explanation for this result?

Hay infusion refers to an amalgamation that can be formed by taking samples from different sources like rivers, lakes, ponds, and others. It is one of the best procedures that can elevate the density of the bacteria cell at any specific time interval.

In the given case, even after boiling hay infusion for one hour, growth was observed in the flask after one day. It can be due to certain factors like the hay infusion may have been comprising some endospore, which is resistant to heat or may comprise some kinds of bacteria that can withstand high temperatures.

Because of which, even after heating the infusion for one hour, it did not get influenced by the heat and got the chance to grow when it got optimum temperature again at the time when the sample was left as such.