Can handling pineapples have an effect on one's fingerprints? I saw this on a 'Hawaii 5-0' episode, still, there must be something to it.

Yes, according to a designer of a fingerprint-verification system designed to work with less-than-optimal prints.

"The people providing the fingerprint samples are subjected to different 'adverse' conditions; from wetness to chemical treatments. Fingerprint images are taken after conditions such as: after a shower, holding pineapples (mild acid from fruit), after washing one’s hands, etc. The characteristics of POPFNN, such as the learning, generalisation, and high computational abilities, make fingerprint verification particularly powerful when verifying authentic fingerprints subjected to external conditions and recognising spurious ones."
https://www.ncbi.nlm.nih.gov/pubmed/11341568

"Workers who cut up pineapples have their fingerprints almost completely obliterated by pressure and the keratolytic effect of bromelain (calcium oxalate crystals and citric acid were excluded as the cause)."
http://tinypineapple.com/gallery/the-pineapple-girl-honolulu

"Repeated exposure of pineapple cutters to bromelain can result in the obliteration of fingerprints."
https://www.drugs.com/npp/pineapple.html