Raw material Boneless, skinless chicken breasts were purchased freshly from the butcher shops. Samples were prepared in average weight of 80±7 g fillets. All fillets including control and treated were packed in polypropylene trays and kept under refrigerated condition (4 °C) for 16 days.
Preparation of LPOS LPOS was made at weight ratios of 1.00; 0.35; 108.70; 1.09 and 2.17 for LPO, glucose oxidase, α-D glucose, KSCN, and KI, respectively (15.5 mg of LPO was added) (Cissé et al. 2012; Harris and KROCHTA 2005; Mohamed et al. 2013). The ingredients were dissolved in 50 mL phosphate buffer. The solution was incubated at 23±2 °C for 24 h using a water bath shaker (shaking at 160 rev min-1) to augment the antimicrobial activity of …show more content…
All samples were preserved in polyethylene trays under refrigerated condition for 16 days.
Kirby-Bauer disc diffusion test For determining of bacterial resistance to alginate-LPOS coating, disc diffusion test was conducted. In this procedure, antimicrobial activity of the coating on specific bacteria including Pseudomonas fluorescens NCTC 10038, Escherichia coli NCTC 12241 was investigated. These organism significantly can be found in in chicken meat (Molin and Ternström 1982; Montville and Matthews 1997). LPOS in concentrations of 0.5, 1, 2, 4, 6, 8 and 10% was added to solution 2. Bacterial suspensions were adjusted to 1.5×108 CFU/mL by 0.5 mcfarland solution then spreaded on the surface of Muller Hinton agar using sterile cotton swabs. Afterward, filter blank paper discs were impregnated with each of two solutions for 3 and 30 seconds, respectively and placed on the surface of the medium. The plates were incubated at 37 °C for 3-4 days. The antibacterial activity of coating was evaluated by measuring the diameter of the inhibition …show more content…
are within the main industrial and commercial indicators of chicken’s spoilage. Thus, the microbiological criteria of Pseudomonas spp. for fresh and refrigerated meat products is recommended 107 or 108 CFU/g (Mead 2004b). If Pseudomonas spp. counts reach this limit, surface slim, lipolysis of lipids and off-odours appear. Pseudomonas aeruginosa is one of the most known groups of Pseudomonas spp. Although, this organism has been recognized as indicator of bottled mineral water (Lund 1986) in Europe, but it is still important in food industry. According to our results, Pseudomonas aeruginosa counts were in range of 2.01-2.98 log CFU/g. So, in opposite of other evaluated bacterial group, this organism had the low and even negative growth rate during 16 days (Fig. 3). So that, the average population of them was 2.04, 2.27, 2.45, 2.50 and 2.54 in T-6, T-4, T-0, T-2 and T-1 samples, respectively on the last day. Also, adding of 6 and 4% LPOS to alginate coating had considerable effect on reducing of bacterial count after day 8. T-6 and T-4 fillets reduced the Pseudomonas aeruginosa by 0.58 and 0.35 log CFU/g, respectively from day 0 to 16. Presented results are in agreement with those of Shokri et al. (2015) (Shokri et al. 2015) who reported the statically difference between LPOS-treated Rainbow Trout Fillets (concentration of 1.25, 2.5, 5 and 7.5% LPOS in whey protein coating) and control batch in associated with pseudomonas spp. population. However, our
Preparation of LPOS LPOS was made at weight ratios of 1.00; 0.35; 108.70; 1.09 and 2.17 for LPO, glucose oxidase, α-D glucose, KSCN, and KI, respectively (15.5 mg of LPO was added) (Cissé et al. 2012; Harris and KROCHTA 2005; Mohamed et al. 2013). The ingredients were dissolved in 50 mL phosphate buffer. The solution was incubated at 23±2 °C for 24 h using a water bath shaker (shaking at 160 rev min-1) to augment the antimicrobial activity of …show more content…
All samples were preserved in polyethylene trays under refrigerated condition for 16 days.
Kirby-Bauer disc diffusion test For determining of bacterial resistance to alginate-LPOS coating, disc diffusion test was conducted. In this procedure, antimicrobial activity of the coating on specific bacteria including Pseudomonas fluorescens NCTC 10038, Escherichia coli NCTC 12241 was investigated. These organism significantly can be found in in chicken meat (Molin and Ternström 1982; Montville and Matthews 1997). LPOS in concentrations of 0.5, 1, 2, 4, 6, 8 and 10% was added to solution 2. Bacterial suspensions were adjusted to 1.5×108 CFU/mL by 0.5 mcfarland solution then spreaded on the surface of Muller Hinton agar using sterile cotton swabs. Afterward, filter blank paper discs were impregnated with each of two solutions for 3 and 30 seconds, respectively and placed on the surface of the medium. The plates were incubated at 37 °C for 3-4 days. The antibacterial activity of coating was evaluated by measuring the diameter of the inhibition …show more content…
are within the main industrial and commercial indicators of chicken’s spoilage. Thus, the microbiological criteria of Pseudomonas spp. for fresh and refrigerated meat products is recommended 107 or 108 CFU/g (Mead 2004b). If Pseudomonas spp. counts reach this limit, surface slim, lipolysis of lipids and off-odours appear. Pseudomonas aeruginosa is one of the most known groups of Pseudomonas spp. Although, this organism has been recognized as indicator of bottled mineral water (Lund 1986) in Europe, but it is still important in food industry. According to our results, Pseudomonas aeruginosa counts were in range of 2.01-2.98 log CFU/g. So, in opposite of other evaluated bacterial group, this organism had the low and even negative growth rate during 16 days (Fig. 3). So that, the average population of them was 2.04, 2.27, 2.45, 2.50 and 2.54 in T-6, T-4, T-0, T-2 and T-1 samples, respectively on the last day. Also, adding of 6 and 4% LPOS to alginate coating had considerable effect on reducing of bacterial count after day 8. T-6 and T-4 fillets reduced the Pseudomonas aeruginosa by 0.58 and 0.35 log CFU/g, respectively from day 0 to 16. Presented results are in agreement with those of Shokri et al. (2015) (Shokri et al. 2015) who reported the statically difference between LPOS-treated Rainbow Trout Fillets (concentration of 1.25, 2.5, 5 and 7.5% LPOS in whey protein coating) and control batch in associated with pseudomonas spp. population. However, our