Utilization of Piper betle L. Extract for Inactivating Foodborne Bacterial Biofilms on Pitted and Smooth Stainless Steel Surfaces

Biofilms are a significant concern in the food industry. The utilization of plant-derived compounds to
inactivate biofilms on food contact surfaces has not been widely reported. Also, the increasing
negative perception of consumers against synthetic sanitizers has encouraged the hunt for natural
compounds as alternatives. Therefore, in this study we evaluated the antimicrobial activities of
ethanol extracts, acetone extracts, and essential oils (EOs) of seven culinary herbs against Salmonella
enterica serotype Typhimurium and Listeria innocua using the broth microdilution assay. Among all
tested extracts and EOs, the ethanol extract of Piper betle L. exhibited the most efficient
antimicrobial activities. To evaluate the biofilm inactivation effect, S. Typhimurium and L. innocua
biofilms on pitted and smooth stainless steel (SS) coupons were exposed to P. betle ethanol extract
(12.5 mg/ml), sodium hypochlorite (NaClO; 200 ppm), hydrogen peroxide (HP; 1100 ppm), and
benzalkonium chloride (BKC; 400 ppm) for 15 min. Results showed that, for the untreated controls,
higher sessile cell counts were observed on pitted SS versus smooth SS coupons. Overall, biofilm
inactivation efficacies of the tested sanitizers followed the trend of P. betle extract ≥ BKC > NaClO >
HP. The surface condition of SS did not affect the biofilm inactivation effect of each tested sanitizer.
The contact angle results revealed P. betle ethanol extract could increase the surface wettability of
SS coupons. This research suggests P. betle extract might be utilized as an alternative sanitizer in
food processing facilities.