A preliminary study on the presence of biofilms on food contact surfaces in selected Sri Lankan fish & shrimp processing factories: setbacks in current cleaning process

Abstract

Biofilms are a matrix of microorganisms which are adhered to and colonized a surface. When formed, they are very difficult to remove and act as a source of contamination in fish and shrimp processing environments. This study was undertaken to investigate the presence of biofilms, their bacterial composition on food contact surfaces in selected fish and shrimp processing factories as there are no records available on this aspect in Sri Lanka. Swabs were taken from selected food contact surfaces in two fish processing factories and two shrimp processing factories 6-8 h after the day's major cleaning operation. Biofilm formation was quantified by Aerobic Plate Count (APC) and Escherichia coli counts. Bacteria present on the biofilms were also identified to their generic or species level.Surface adhered bacteria in surveyed fish processing plants had different levels of APCs [in Colony forming units (CFU)]: on deheading and lolling tables 103 cfu/cm2; filleting boards 103 cfu/cm2; trimming boards 104 cfu/cm2; knives 106 cfu/knife; gloves 105 cfu/glove; storage boxes (plastic) 105 cfu/cm2; small cutting boards 106 cfu/cm2; water buckets 106 cfu/bucket. E. coli were found only on some of the food contact surfaces viz. knives (5.0 cfu/knife); storage boxes and filleting boards (