Evaluation of ultraviolet radiation to control microorganisms adhering to low-density polyethylene films

Abstract

Efficiency of ultraviolet (UV) radiation in reducing the cell number of Staphylococcus aureus ATCC 25923 and Escherichia coli K-12 adhered to low-density polyethylene (LDPE) films was evaluated. The microorganisms were let to adhere to the surface of LPDE bags for 12h at 18ºC, and then submitted to UV radiation at an intensity 196 µW.cm -2 , 254nm, for 2 seconds. Staphylococcus aureus was less resistant to UV radiation than E. coli, and the efficiency increased with the increase of the concentration of microbial suspension. After 1500 hours of use the UV radiation intensity of the lamp was reduced from 288 to 78 µW.cm -2 , and the higher decrease occurred in the first 100 hours of use. Also, the efficiency of the UV radiation decreased after 1500 hours of use. The number of mesophilic aerobes on the surface of LDPE films was reduced by 90% after irradiation with 137 µW.cm -2 for 2 seconds. Atomic force microscopy revealed cracks and crevices and protuberances on the LDPE surface, a topography that can protect the cells from UV radiation, reducing the efficiency of the process. The results showed that UV radiation can be a useful technique for reducing the microbiota adhered to LDPE films.

The adherence of Pseudomonas fluorescens to marble, granite, synthetic polymers, and stainless steel

“…Similar to our results, the ability of a number of microorganisms to adhere to different surfaces has been investigated in several studies (AKUTSU, 2001;BERESFORD et al, 2001;DI MARTINO et al, 2003;FLINT et al, 2001;HJELM et al, 2001;LEREBOUR et al, 2004;MASSON et al, 2002;MOREIRA, 2002;PARIZZI et al, 2003;POMPERMAYER;SILVA et al, 2003;TYRER et al, 2004;WONG et al, 2002;ZAQUES et al, 2000). We found differences in the adherence of P. fluorescens depending on the surface and contact time (p < 0.05).…”

“…There are also some types of polyvinyl chloride (PVC), polyurethane, and silicone, which are bottom face-coated with cloth and have been used as conveyors in several food industries such as fruits and vegetables processors, meat and poultry, bakery, confectionery, and pasta processing, which should be more carefully studied with regards to microbial adherence (LELIEVELD et al, 2005). Microbial adhesion has been evaluated in a large number of food processing contact surfaces including stainless steel, glass, rubber, formic, polypropylene, and polycarbonate ( SILVA, et al, 2003;ZAQUEUS et al, 2000). Teflon and cast iron can support microbial growth if a thin layer of food residue is present conditioning the surface to allow bacterial growth (JULLIEN et al, 2002;WONG et al, 2002).…”

“…It has long been recognized that equipment and utensil surfaces can help microorganisms adhere, grow, and become a source of spoilage and pathogenic microorganisms (BEECH, 2004;MIDELET;O'TOOLE et al;STOODLEY et al, 2002). Pseudomonas aeruginosa (PARSEK;GREENBERG, 2000;HEYDOM et al, 2002;SAUER et al, 2002), Pseudomonas fluorescens ( MASSON et al, 2002;ROSSONI;TYRER et al, 2004;VALCARCE et al, 2002), and Shewanella putrefaciens (HJELM et al, 2002) are members of the spoilage bacteria.…”

Chemical and Microbiological Aspects of the Interaction Between Food and Food Packages

“…Available reported data suggest that the adhesion of micro-organisms to food packages affects many factors, such as superficial electric charges and pH values [22]. Moreover, the interaction between foods in close contact with packages and inner surfaces affects the degree of microbial adhesion [23].…”

Microbiological contamination of surfaces in fish industry

“…Microorganism contamination of equipment and utensils is a risk factor in the food industry, therefore the choice of material they are made of must be based on their mechanical and anti-corrosive properties and on the ease of hygienization (Silva et al, 2003;Fuster-Valls et al ., 2008). Some studies have reported high incidence of microorganisms in equipment and utensils in foodprocessing areas caused by failures in employing correct hygienization techniques, which results in serious public health or economic issues (Temelli et al, 2006;Oliveira et al, 2008, Kahraman et al, 2010.…”