Fermented foods play a very important role in Cambodian health and nutrition,as well as other developing countries where food preservation methods may be limited.SIENG,a Khmer fermented soybean product,naturally conta...Fermented foods play a very important role in Cambodian health and nutrition,as well as other developing countries where food preservation methods may be limited.SIENG,a Khmer fermented soybean product,naturally contains both beneficial and pathogenic microorganisms.Traditional fermentation that relies on natural microbial flora and environmental conditions results in variable product quality and can lead to spoilage.A starter culture such as Bacillus subtilis can ensure the safety and stability of the products.The objective of this study is to control the growth of Gram positive pathogens contaminated into traditional fermented soybean(SEING)by using antimicrobial Bacillus subtilis isolated from the same kind of food.Out of 120 SIENG samples,49 B.cereus strains were isolated,and 12 of B.cereus were positively synthesized compared with the lyophilized control enterotoxin.Two of these strains(BTM8-7 and BTM8-8)produced high levels of enterotoxin.We identified five Bacillus strains with the ability to fight against indicator pathogenic microorganisms.Among the five strains,B.CeM6-2 had the highest activity level against Lactobacillus plantrum ATCC 8014 and the largest diameter.B.CeM6-2 tolerated up to 20 h at 30℃ and 22 h at 37℃.In testing the strains with PK and PK-PMSF enzymes,bacteriocin produced by the strain B.CeM6PK untreated and B.CeM6-2PK-PMSF had a significantly stronger ability to suppress all the pathogenic indicators from 0 h to 47 h compared to the B.CeM6-2PK.Moreover,CeM6-2 outperformed the Miyagino strains,as it actively produced bacteriocin that fought against all four indicator strains of Gram positive and lactic acid groups,especially against Listeria monocytogenes,Streptococcus pyrogene,Leuconostoc mesenterids and L.plantarum,from 0 h-58 h and 0 h-40 h at 35℃.CeM6-2(1%)strain had the highest ability to fight against B.cereus at 24 h and at 34 h to 44 h incubation as well.CeM6-2(10:0 mL)and CeM6-2(9:1 mL)have the strongest ability to fight against B.cereus at room temperature(48 h and 72 h).The longer incubation and time at room temperature produce the highest level of bacteriocin.Thus,bacteriocins produced by B.CeM6-2 can be used as a preservative in food processing industries to avoid food spoilage even in higher temperatures and time.展开更多
The experiment was conducted at laboratory of the faculty of Agro-industry,Royal University of Agriculture,locating in Phnom Penh city,commenced from August to October,2023.The single factor CRD(Completely Randomized ...The experiment was conducted at laboratory of the faculty of Agro-industry,Royal University of Agriculture,locating in Phnom Penh city,commenced from August to October,2023.The single factor CRD(Completely Randomized Design)was used with 6 treatments and 3 replications.While the 7 ingredients were used such as tomato,sugar,salt,onion,bell pepper,sodium benzoate and vinegar,with or without stabilizers.After processing,the sauce was kept in room temperature to observe the self-life and the variation of nutrients contain in 8 weeks.The chemical compositions in the sauce were analyzed to identify the variation during storing in the temperature room.Through the findings showed that the pH value,Total soluble solids and Color(L,A&B)of all treatments has decreased in 8th week comparing to starting point,while the Total acids increased.If comparing among the 6 treatments,after the products have produced(w0),all the chemical compositions in group T0 containing the lowest,exception of Fat and Color(L).When the self-life up to eight weeks,all the composition parameters were statistically different(except for Moisture,Ash,Dry Mass,and Fat).For identification the Bacteria presenting showed that there was no present in first day of self-life until the first week.The present of bacteria were detected from 2nd week to 8th week,excepted T0.The CFU of T0 had the lowest number of colonies,while T3 had the highest once.At the same time,we found that the number of colonies decreases with the age of storage(self-life),which means that at the beginning of growing in the second week,it had higher amount(from 2.10 to 2.69 of CFU as log);while this number decreased with the shelf life up to 8 weeks,which is between 0 to 2.35.展开更多
文摘Fermented foods play a very important role in Cambodian health and nutrition,as well as other developing countries where food preservation methods may be limited.SIENG,a Khmer fermented soybean product,naturally contains both beneficial and pathogenic microorganisms.Traditional fermentation that relies on natural microbial flora and environmental conditions results in variable product quality and can lead to spoilage.A starter culture such as Bacillus subtilis can ensure the safety and stability of the products.The objective of this study is to control the growth of Gram positive pathogens contaminated into traditional fermented soybean(SEING)by using antimicrobial Bacillus subtilis isolated from the same kind of food.Out of 120 SIENG samples,49 B.cereus strains were isolated,and 12 of B.cereus were positively synthesized compared with the lyophilized control enterotoxin.Two of these strains(BTM8-7 and BTM8-8)produced high levels of enterotoxin.We identified five Bacillus strains with the ability to fight against indicator pathogenic microorganisms.Among the five strains,B.CeM6-2 had the highest activity level against Lactobacillus plantrum ATCC 8014 and the largest diameter.B.CeM6-2 tolerated up to 20 h at 30℃ and 22 h at 37℃.In testing the strains with PK and PK-PMSF enzymes,bacteriocin produced by the strain B.CeM6PK untreated and B.CeM6-2PK-PMSF had a significantly stronger ability to suppress all the pathogenic indicators from 0 h to 47 h compared to the B.CeM6-2PK.Moreover,CeM6-2 outperformed the Miyagino strains,as it actively produced bacteriocin that fought against all four indicator strains of Gram positive and lactic acid groups,especially against Listeria monocytogenes,Streptococcus pyrogene,Leuconostoc mesenterids and L.plantarum,from 0 h-58 h and 0 h-40 h at 35℃.CeM6-2(1%)strain had the highest ability to fight against B.cereus at 24 h and at 34 h to 44 h incubation as well.CeM6-2(10:0 mL)and CeM6-2(9:1 mL)have the strongest ability to fight against B.cereus at room temperature(48 h and 72 h).The longer incubation and time at room temperature produce the highest level of bacteriocin.Thus,bacteriocins produced by B.CeM6-2 can be used as a preservative in food processing industries to avoid food spoilage even in higher temperatures and time.
文摘The experiment was conducted at laboratory of the faculty of Agro-industry,Royal University of Agriculture,locating in Phnom Penh city,commenced from August to October,2023.The single factor CRD(Completely Randomized Design)was used with 6 treatments and 3 replications.While the 7 ingredients were used such as tomato,sugar,salt,onion,bell pepper,sodium benzoate and vinegar,with or without stabilizers.After processing,the sauce was kept in room temperature to observe the self-life and the variation of nutrients contain in 8 weeks.The chemical compositions in the sauce were analyzed to identify the variation during storing in the temperature room.Through the findings showed that the pH value,Total soluble solids and Color(L,A&B)of all treatments has decreased in 8th week comparing to starting point,while the Total acids increased.If comparing among the 6 treatments,after the products have produced(w0),all the chemical compositions in group T0 containing the lowest,exception of Fat and Color(L).When the self-life up to eight weeks,all the composition parameters were statistically different(except for Moisture,Ash,Dry Mass,and Fat).For identification the Bacteria presenting showed that there was no present in first day of self-life until the first week.The present of bacteria were detected from 2nd week to 8th week,excepted T0.The CFU of T0 had the lowest number of colonies,while T3 had the highest once.At the same time,we found that the number of colonies decreases with the age of storage(self-life),which means that at the beginning of growing in the second week,it had higher amount(from 2.10 to 2.69 of CFU as log);while this number decreased with the shelf life up to 8 weeks,which is between 0 to 2.35.
