It has become necessary to assess how food processing methods affect qualitative qualities due to the increased consumer awareness of the health benefits of various nutrients in food. In the current study, the effects...It has become necessary to assess how food processing methods affect qualitative qualities due to the increased consumer awareness of the health benefits of various nutrients in food. In the current study, the effects of ultrasound treatment (37°C, 5 min), pasteurization (90°C, 5 min), and their combination on quality parameters, including pH, total soluble solids (TSSs), titratable acidity (TA), color values (L*, a*, b*), ascorbic acid (AA), total phenolic content (TPC), and antioxidant activity (DPPH), of pineapple juice from ripe and overripe pineapples were assessed. Color values (L*), ascorbic acid (AA), total phenolic content (TPC), and DPPH radical scavenging activity in all juice samples that were sonicated alone and in combination with pasteurization improved significantly (p and color value (a* and b*) decreased in comparison to the control. Whereas pH and acidity did not change significantly (p < 0.05). Pasteurization significantly (p , but sonicated samples significantly (p quality parameters and antioxidant activity, notably in ripe juice. Overall, pasteurization degraded these liquids but sonication, either alone or in combination with it, was advantageous for preserving their quality by retaining nutrients.展开更多
We developed a novel rapid hygrothermal pasteurization (RHP) method using saturated water vapor with a dew point of 100℃. The aim of this paper is to compare the effect of RHP treatment versus conventional sodium hyp...We developed a novel rapid hygrothermal pasteurization (RHP) method using saturated water vapor with a dew point of 100℃. The aim of this paper is to compare the effect of RHP treatment versus conventional sodium hypochlorite (NaClO) treatments on inactivation of natural mesophilic bacteria and quality attributes on fruits and vegetables. The RHP treatment was performed within a second by free-falling samples (cabbage, cucumber, carrot, bell pepper, pineapple and melon) through cylindrical processing chamber filled with steam. NaClO treatment was performed by washing samples with NaClO solution (100 mg/mL of free chlorine (pH 7), for 1 min). The RHP treatment showed a significantly higher inactivation effect than NaClO treatment on all tested samples. The RHP treatment had a slightly larger influence on color and vitamin C content than NaClO treatment in cabbage. Furthermore, the effects of treatment time and operated temperature were also determined using microbial model system. Elongation of treatment time did not significantly increase the microbial inactivation effect. Lowering of operated temperature by mixing air into steam tended to decrease the inactivation effect. From these results, RHP treatment could be used as an alternative method for decontaminating microorganisms on fruits and vegetables, except on leafy vegetable. In addition, it is suggested that microbial inactivation by RHP treatment was achieved through the initial condensation stage of water vapor on sample surface. By contrast, interfusion of air disturbed the effective condensation of water vapor.展开更多
Boiling of water, for purification, commonly practiced in the world, has many problems associated with it like danger of scalding, scaling in the vessels, removal of useful minerals and blandness of taste etc. Water c...Boiling of water, for purification, commonly practiced in the world, has many problems associated with it like danger of scalding, scaling in the vessels, removal of useful minerals and blandness of taste etc. Water can be made safe for drinking simply by heating at 65℃ for 6 minutes. A colour indicating strip was developed which changes colour from red to purple at 67℃. Use of this strip can help in pasteurizing water without the above problems and with considerable energy saving.展开更多
The Adansonia digitate L. known as Baobab is the only species present in West Africa and grows wild. All parts of the plant are used by humans. In Senegal, baobab pulp is widely consumed;it is used as raw material in ...The Adansonia digitate L. known as Baobab is the only species present in West Africa and grows wild. All parts of the plant are used by humans. In Senegal, baobab pulp is widely consumed;it is used as raw material in small and medium enterprises (SMEs) for making juices, concentrates, jams, powder. Drinks or juices from baobab are highly appreciated by consumers;however rapid fermentation can happen even after pasteurization that can shorten their shelf-life. A Doehlert experimental design was used to find a good scale of heat treatment ensuring a proper conservation of baobab juice. Results of the experimental design showed that a heat treatment of 80°C for 10 min gives a baobab juice with good sanitary quality that meets the international standards.展开更多
Protein hydrolysate prepared from fish and shrimp by-products were used to prepare a seasoning protein hydrolysate （SPH）. The effects of pasteurization and storage on total phenolic content （TPC）, DPPH radical sca...Protein hydrolysate prepared from fish and shrimp by-products were used to prepare a seasoning protein hydrolysate （SPH）. The effects of pasteurization and storage on total phenolic content （TPC）, DPPH radical scavenging activity, reducing power, and color of the SPH were investigated. Pasteurization at 90 ℃ for 10 minutes led to a reduction of TPC and DPPH radical scavenging activity and an increase of reducing power of solid fraction of SPH by about 30%, 99%, and 100%, respectively. Consequently it increased TPC DPPH radical scavenging activity, and reducing power of the liquid phase by about 32%, 600%, and 100%, respectively. Storage at 28, 35, or 45 ℃ for 12 weeks altered color values and increased brownness intensity （OD420）. The storage led to an apparent increase of the TPC and antioxidative activity of the product. The results indicate the possibility of producing healthy appetizers from protein hydrolysate prepared from by-products of the seafood industry.展开更多
The purpose of this study was to evaluate the sensory property and shelf life of the processed mpedli beer using aqueous leaves extract of Vernonia amygdalina(VA)and heat treatment.The white sorghum beer was made at t...The purpose of this study was to evaluate the sensory property and shelf life of the processed mpedli beer using aqueous leaves extract of Vernonia amygdalina(VA)and heat treatment.The white sorghum beer was made at the laboratory scale using home-made procedure(Control).Following filtration,the beer was blended with an aqueous leaf extract(1/10,v/v)of VA(BUB).Pasteurization(60°C/30 min)was performed on a portion of the VA blended sample(BPB).The sensory parameters and shelf life of the three samples were evaluated at room temperature during a month storage.The sensory characteristics of blended and non-supplemented mpedli beer differed significantly(p<0.05).During storage,the colour,bitterness,aroma,odour,viscosity,texture,and overall acceptability of the processed samples were improved.Bitterness(r=0.898;p<0.01)and odour(r=0.930;p<0.01)were both highly correlated with the acceptance of the processed beer.The non-supplemented samples had the highest sensory scores 48 hours after preparation,while the relevant sensory ratings in processed BUB and BPB samples were recorded from the 12th to the 21st and 27th day of storage,respectively.The findings suggest that combining pasteurization with addition of aqueous leaf extract of VA may help small-scale brewers for improving the sensory quality and extending the shelf life of mpedli.According to the findings,the use of bitter leaf could be proposed as an alternative hop in the local brewing industry and may increase incomes of producers of local sorghum beer.展开更多
Three different apple-carrot juice blends (60:40, 75:25 and 90:10, v/v) were prepared and treated with ultrasound with comparison to the conventional thermal pasteurization. Total aerobic viable count (TAC) were signi...Three different apple-carrot juice blends (60:40, 75:25 and 90:10, v/v) were prepared and treated with ultrasound with comparison to the conventional thermal pasteurization. Total aerobic viable count (TAC) were significantly lower in juice blends with lower pH (apple-carrot ratio of 90:10, v/v) than the blends with higher pH after one month storage at 4?C. TAC were similar in ultrasound-treated and thermal pasteurized juice blends. Changes of turbidity of juice during storage followed the same pattern of TAC. Other juice quality parameters such as color, pH, titratable acid, total soluble solids, antioxidant capacity and beta-carotene did not change significantly during the storage period. The results suggest that ultrasound treatment has a potential to use as an alternative non-thermal technique for traditional thermal pasteurization process for maintaining the quality of beverages prepared from fruit and vegetable juices.展开更多
Fermented tigernut milk (FTM) was prepared from three different varieties (fresh yellow, big and small dry brown) of tigernut (Cyperus esculenta) obtained from Bodija market, Ibadan, Oyo state. Fifty two microbial iso...Fermented tigernut milk (FTM) was prepared from three different varieties (fresh yellow, big and small dry brown) of tigernut (Cyperus esculenta) obtained from Bodija market, Ibadan, Oyo state. Fifty two microbial isolates were obtained from FTM at different fermentation times, 32 of which were on MRS agar, 12 on nutrient agar and 8 on malt extract agar. Lactic acid bacteria were identified as Lactobacillus plantarum (LP), Lactococcus lactis (LC), Lactobacillus brevis, Lactococcus cremoris, Lactobacillus bulgaricus and Lactococcus thermophilus (LT). The non-LAB identified includes E. coli, Bacillus species and Proteus species while the yeasts include Saccharomyces cerevisiae and Candida kefyr. Lactic acid bacteria were found to predominate the total microflora of the FTM with their count ranging between 2.0 × 104 cfu/ml to 2.0 × 108 cfu/ml. Microbiological examination revealed that the FTM was safe for consumption as non-LAB counts were below the limit of acceptance which is 2.0 × 105 cfu/ml for dairy milk by Codex Alimentarius Commission. The quantity of lactic acid produced by the LAB isolates ranged between 0.86 g/l - 2.86 g/l while that of hydrogen peroxide ranged between 0.16 g/l - 0.51 g/l. Starter cultures were selected based on predominance of isolate, physiological characteristics, quantity of lactic acid and hydrogen peroxide production. The tiger nut varieties were fermented with the following starter combinations LP, LP/LC, LP/LC/LT, LP/LT while the fifth was spontaneously fermented. The nutritional, chemical and sensory properties of the starter fermented tiger nut milk were evaluated. The highest protein content (24.80%) was obtained in FTM with mixed cultures of LP/LC/LT while the least (3.00%) was obtained in spontaneously fermented milk. There was a significant difference in the FTM varieties. The highest fat content (9.40%) was obtained in spontaneously fermented tiger nut milk while the least (3.40%) was found in FTM with mixed cultures of LP/LC/LT. Fermentation decreased the pH and increased the lactic acid of the starter developed FTM, while sensory evaluation test showed that the FTM with mixed cultures of LP/LC/LT was highly acceptable. In conclusion, an excellent and acceptable FTM can be produced using treatments which comprise of pasteurization at 90°?for 15 minutes, fermentation at 45℃?for 18 hours using mixed cultures of Lactobacillus plantarum, Lactococcus lactis and Lactococcus thermophilus.展开更多
Liquid food industries use different preservation methods to extend the shelf life of products by reducing both enzymatic and microorganism activities.Emerging non-thermal pasteurization techniques are applied in orde...Liquid food industries use different preservation methods to extend the shelf life of products by reducing both enzymatic and microorganism activities.Emerging non-thermal pasteurization techniques are applied in order to avoid thermal processes maintaining the microbial safety and quality of liquid foods.Non-thermal preservation technologies used in the liquid food industry include high-pressure processing(HPP),pulsed electric field(PEF),ultraviolet light(UV-C)and ultra-sonication(US).HPP is a method to target specific organisms by applying a pressure range of 100-1,000 MPa.PEF uses short pulses of a strong electric field applied to a flowing liquid food which affects the whole cell membrane of the organism.UV-C treatment at 253.7 nm has been proven to be appropriate for maintaining liquid quality and minimal deterioration of nutrients.US is applied to liquid foods in a lower frequency range of 20-100 kHz and a higher sound intensity of 10-1,000 W/cm2 to the breakdown of cells.According to scientific literature,those methods have been applied to fruit juices like orange,apple,pear,coconut water,etc.Most of the non-thermal methods achieved the Food and Drug Administration(FDA)requirement of a 5-log reduction of microorganisms without deteriorating the sensory and nutritional attributes of fruit juices.Some of these methods have already been commercialized and others are still in a pilot scale.This study gives a comprehensive overview of published literature regarding the potential for using non-thermal pasteurization methods to extend the shelf life of different fruit juices with minimal deterioration of nutritional and sensory quality.展开更多
BACKGROUND Breast milk is the primary source of nutrition for newborns.Hospitalized babies frequently need nutritional support from Human Milk Banks.As bacterial species of the genus Enterococcus are part of the micro...BACKGROUND Breast milk is the primary source of nutrition for newborns.Hospitalized babies frequently need nutritional support from Human Milk Banks.As bacterial species of the genus Enterococcus are part of the microbiota of healthy donors,they may contaminate samples of pumped breast milk.AIM To identify and characterize the bacterial virulence and resistance in samples isolated from the nipple-areolar region,hands,and breast milk aliquots from donors at the Human Milk Bank of Municipal Hospital EsauMatos in the city of Vitória da Conquista,Bahia State,Brazil.METHODS The personal hygiene and sanitation of donors were analyzed with the aim of identifying possible reasons for contamination of pumped milk.Cutaneous samples as well as aliquots of unpasteurized and pasteurized milk from 30 participants were obtained.Each Enterococcus spp.isolate underwent a disk diffusion susceptibility test and molecular biology techniques to determine resistance and virulence genes.RESULTS Enterococcus spp.were identified in 30%of donors(n=9),and 11 specimens were isolated.Resistance to tetracycline was highly prevalent,being detectable in 63%of the isolates(n=7)and followed by intermediate sensitivity to ciprofloxacin,observed in 27%of the specimens(n=3).The efaA gene was found in 63%(n=7)of the isolates,while the ace gene was detected in 27%(n=3).CONCLUSION This study illustrates the importance of microbiological monitoring by Human Milk Banks and the need for alternatives to prevent the presence of Enterococcus spp.in hospital settings.展开更多
Background: The present experiment was performed to assess the effects of different sources of milk on the growth performance, serum metabolism, immunity, and intestinal development of calves. Eighty-four Holstein mal...Background: The present experiment was performed to assess the effects of different sources of milk on the growth performance, serum metabolism, immunity, and intestinal development of calves. Eighty-four Holstein male neonatal calves were assigned to one of the following four treatment groups: those that received bunk tank milk(BTM), untreated waste milk(UWM), pasteurized waste milk(PWM), and acidified waste milk(AWM) for 21 d.Results: Calves in the BTM and AWM groups consumed more starter(P < 0.05) than those in the UWM group.Average daily gain in the UWM group was the highest(P < 0.05). Calves exhibited the highest(P < 0.05) serum total protein, albumin, total cholesterol, high density lipoprotein, triglycerides, growth hormone, immunoglobulin(Ig) A and Ig M concentrations in the UWM group, highest malondialdehyde and tumor necrosis factor-α in the PWM group(P < 0.05), and highest glutathione peroxidase and Ig G in the BTM group(P < 0.05). The jejunum and ileum of the calves in all treatments presented a slight inflammatory response. The jejunal inflammation scores were higher(P < 0.05) in the UWM and AWM groups than the BTM group; the ileal inflammation scores increased more(P < 0.05) in the AWM group than the BTM group. Jejunal immunohistochemical scores(IHS) were higher(P < 0.05) in the PWM and AWM groups than the BTM group. Compared to the other three groups, calves feeding on BTM had lower(P < 0.05) ileal IHS. Jejunal interleukin(IL)-1β, IL-8, and IL-10 mRNA expression in the UWM group was the highest(P < 0.05). Calves fed AWM increased(P < 0.05) mRNA expression of IL-8 and toll like receptor 4(TLR-4) in the jejunum and IL-8, IL-1β, IL-6, IL-8, and IL-10 in the mesenteric lymph nodes.Conclusions: Overall, bunk tank milk is the best choice for calf raising compared to waste milk. The efficiency of feeding pasteurized and acidified waste milk are comparable, and the acidification of waste milk is an acceptable labor-saving and diarrhea-preventing feed for young calves.展开更多
Objective:To determine the presence and levels of microbes in unexpired pasteurized milk from randomly selected supermarkets in Kingston,Jamaica.Methods:The quantitative study used a stratified random sampling techniq...Objective:To determine the presence and levels of microbes in unexpired pasteurized milk from randomly selected supermarkets in Kingston,Jamaica.Methods:The quantitative study used a stratified random sampling technique in the selection of the 20 representative milk samples from six(6) supermarkets.Microbiological tests such as methylene blue reduction,standard plate count(SPC),coliform plate count(CPC),purity plate culture,gram staining and biochemical tests were performed to examine the microbes in purchased unexpired pasteurized milk.Results:One sample(BCr016) had a pH of 4.0.a rancid odour and curdled appearance.It decolourized within one hour during the methylene blue reduction test and was classified as class 4 milk.Seven of the samples were sterile with no microbe growth on the plate count agar and violet red bile salt agar(VRBA).The milk samples that appeared to be safe for consumption were all 10,11,12 and 13 days before expiration.The VRBA sample BCr016,had a colony count of 13 400 CFU/ mL.There was the presence of Escherichia coli in sample LCr021 which had a standard plate count of 1 580 SPC/mL and a coliform count of 500 CFU/mL.Enterobacter sp.was present in colonies from BCr016 and all the other milk samples.Conclusions:Unacceptable levels of Entembacter spp.and Escherichia coli were found in most of the samples.Effective measures to ensure safe milk for human consumption such as the phosphatase test and methylene blue reduction test should be routinely performed on each batch of milk processed by dairy plants.展开更多
Differentiating pasteurized milk and reconsti-tuted milk by scientific approach was necessary to defend consumer from economic fraud of wrong labeling. In this paper 2DGE (2 Dimen-sional Gel Electrophoresis)-coomassie...Differentiating pasteurized milk and reconsti-tuted milk by scientific approach was necessary to defend consumer from economic fraud of wrong labeling. In this paper 2DGE (2 Dimen-sional Gel Electrophoresis)-coomassie brilliant blue staining method was employed and sig-nificant color intensity changing was observed among raw milk, pasteurized milk, UHT milk and reconstituted milk. For example, the intensity of 10 protein spots including casein and lac-toglobulin reduced more than two folds from pasteurized milk to reconstituted milk. However, DIGE (Differential Gel Electrophoresis) assay showed that the majority protein remained simi-lar level from pasteurized milk to reconstituted milk. Therefore the color fading of coomassie brilliant blue stained 2D gels may be due to other biochemical reaction, such as Maillard reaction, instead of protein degradation. Stability of 2DGE pattern was confirmed by running six gels of the same sample in parallel and software analysis showed that all proteins were at similar level. Two commercialized pasteurized milk samples and one reconstituted milk sample were tested by 2DGE-coomassie blue staining method and re-constituted milk could be easily identified.展开更多
Pasteurized milk contains complex microbial communities affected by sterilization and storage conditions.This complex microflora may be the possible reason that pasteurized dairy products are highly prone to spoilage....Pasteurized milk contains complex microbial communities affected by sterilization and storage conditions.This complex microflora may be the possible reason that pasteurized dairy products are highly prone to spoilage.In this study,packaged pasteurized milk products collected from dairy processing factories in China were stored at 0,4,10,15,and 25℃ for 0−15 days and subjected to microbial identification using high-throughput sequencing.Accordingly,6 phyla and 44 genera were identified as the dominant microbiota.Moreover,the changes in nutritional composition of the pasteurized milk,including in 16 free amino acids,7 taste values,and 8 chemical constituents,were analyzed using principal component and multi-factor analyses.The Pearson correlation analysis identified Pseudomonas,Aeromonas,Paenibacillus,and Serratia genera as the core functional microbiota that significantly affects the nutritional composition of pasteurized milk.Hence,the results provide a comprehensive understanding of the safety and shelf-life of stored pasteurized milk.展开更多
文摘It has become necessary to assess how food processing methods affect qualitative qualities due to the increased consumer awareness of the health benefits of various nutrients in food. In the current study, the effects of ultrasound treatment (37°C, 5 min), pasteurization (90°C, 5 min), and their combination on quality parameters, including pH, total soluble solids (TSSs), titratable acidity (TA), color values (L*, a*, b*), ascorbic acid (AA), total phenolic content (TPC), and antioxidant activity (DPPH), of pineapple juice from ripe and overripe pineapples were assessed. Color values (L*), ascorbic acid (AA), total phenolic content (TPC), and DPPH radical scavenging activity in all juice samples that were sonicated alone and in combination with pasteurization improved significantly (p and color value (a* and b*) decreased in comparison to the control. Whereas pH and acidity did not change significantly (p < 0.05). Pasteurization significantly (p , but sonicated samples significantly (p quality parameters and antioxidant activity, notably in ripe juice. Overall, pasteurization degraded these liquids but sonication, either alone or in combination with it, was advantageous for preserving their quality by retaining nutrients.
文摘We developed a novel rapid hygrothermal pasteurization (RHP) method using saturated water vapor with a dew point of 100℃. The aim of this paper is to compare the effect of RHP treatment versus conventional sodium hypochlorite (NaClO) treatments on inactivation of natural mesophilic bacteria and quality attributes on fruits and vegetables. The RHP treatment was performed within a second by free-falling samples (cabbage, cucumber, carrot, bell pepper, pineapple and melon) through cylindrical processing chamber filled with steam. NaClO treatment was performed by washing samples with NaClO solution (100 mg/mL of free chlorine (pH 7), for 1 min). The RHP treatment showed a significantly higher inactivation effect than NaClO treatment on all tested samples. The RHP treatment had a slightly larger influence on color and vitamin C content than NaClO treatment in cabbage. Furthermore, the effects of treatment time and operated temperature were also determined using microbial model system. Elongation of treatment time did not significantly increase the microbial inactivation effect. Lowering of operated temperature by mixing air into steam tended to decrease the inactivation effect. From these results, RHP treatment could be used as an alternative method for decontaminating microorganisms on fruits and vegetables, except on leafy vegetable. In addition, it is suggested that microbial inactivation by RHP treatment was achieved through the initial condensation stage of water vapor on sample surface. By contrast, interfusion of air disturbed the effective condensation of water vapor.
文摘Boiling of water, for purification, commonly practiced in the world, has many problems associated with it like danger of scalding, scaling in the vessels, removal of useful minerals and blandness of taste etc. Water can be made safe for drinking simply by heating at 65℃ for 6 minutes. A colour indicating strip was developed which changes colour from red to purple at 67℃. Use of this strip can help in pasteurizing water without the above problems and with considerable energy saving.
文摘The Adansonia digitate L. known as Baobab is the only species present in West Africa and grows wild. All parts of the plant are used by humans. In Senegal, baobab pulp is widely consumed;it is used as raw material in small and medium enterprises (SMEs) for making juices, concentrates, jams, powder. Drinks or juices from baobab are highly appreciated by consumers;however rapid fermentation can happen even after pasteurization that can shorten their shelf-life. A Doehlert experimental design was used to find a good scale of heat treatment ensuring a proper conservation of baobab juice. Results of the experimental design showed that a heat treatment of 80°C for 10 min gives a baobab juice with good sanitary quality that meets the international standards.
文摘Protein hydrolysate prepared from fish and shrimp by-products were used to prepare a seasoning protein hydrolysate （SPH）. The effects of pasteurization and storage on total phenolic content （TPC）, DPPH radical scavenging activity, reducing power, and color of the SPH were investigated. Pasteurization at 90 ℃ for 10 minutes led to a reduction of TPC and DPPH radical scavenging activity and an increase of reducing power of solid fraction of SPH by about 30%, 99%, and 100%, respectively. Consequently it increased TPC DPPH radical scavenging activity, and reducing power of the liquid phase by about 32%, 600%, and 100%, respectively. Storage at 28, 35, or 45 ℃ for 12 weeks altered color values and increased brownness intensity （OD420）. The storage led to an apparent increase of the TPC and antioxidative activity of the product. The results indicate the possibility of producing healthy appetizers from protein hydrolysate prepared from by-products of the seafood industry.
文摘The purpose of this study was to evaluate the sensory property and shelf life of the processed mpedli beer using aqueous leaves extract of Vernonia amygdalina(VA)and heat treatment.The white sorghum beer was made at the laboratory scale using home-made procedure(Control).Following filtration,the beer was blended with an aqueous leaf extract(1/10,v/v)of VA(BUB).Pasteurization(60°C/30 min)was performed on a portion of the VA blended sample(BPB).The sensory parameters and shelf life of the three samples were evaluated at room temperature during a month storage.The sensory characteristics of blended and non-supplemented mpedli beer differed significantly(p<0.05).During storage,the colour,bitterness,aroma,odour,viscosity,texture,and overall acceptability of the processed samples were improved.Bitterness(r=0.898;p<0.01)and odour(r=0.930;p<0.01)were both highly correlated with the acceptance of the processed beer.The non-supplemented samples had the highest sensory scores 48 hours after preparation,while the relevant sensory ratings in processed BUB and BPB samples were recorded from the 12th to the 21st and 27th day of storage,respectively.The findings suggest that combining pasteurization with addition of aqueous leaf extract of VA may help small-scale brewers for improving the sensory quality and extending the shelf life of mpedli.According to the findings,the use of bitter leaf could be proposed as an alternative hop in the local brewing industry and may increase incomes of producers of local sorghum beer.
文摘Three different apple-carrot juice blends (60:40, 75:25 and 90:10, v/v) were prepared and treated with ultrasound with comparison to the conventional thermal pasteurization. Total aerobic viable count (TAC) were significantly lower in juice blends with lower pH (apple-carrot ratio of 90:10, v/v) than the blends with higher pH after one month storage at 4?C. TAC were similar in ultrasound-treated and thermal pasteurized juice blends. Changes of turbidity of juice during storage followed the same pattern of TAC. Other juice quality parameters such as color, pH, titratable acid, total soluble solids, antioxidant capacity and beta-carotene did not change significantly during the storage period. The results suggest that ultrasound treatment has a potential to use as an alternative non-thermal technique for traditional thermal pasteurization process for maintaining the quality of beverages prepared from fruit and vegetable juices.
文摘Fermented tigernut milk (FTM) was prepared from three different varieties (fresh yellow, big and small dry brown) of tigernut (Cyperus esculenta) obtained from Bodija market, Ibadan, Oyo state. Fifty two microbial isolates were obtained from FTM at different fermentation times, 32 of which were on MRS agar, 12 on nutrient agar and 8 on malt extract agar. Lactic acid bacteria were identified as Lactobacillus plantarum (LP), Lactococcus lactis (LC), Lactobacillus brevis, Lactococcus cremoris, Lactobacillus bulgaricus and Lactococcus thermophilus (LT). The non-LAB identified includes E. coli, Bacillus species and Proteus species while the yeasts include Saccharomyces cerevisiae and Candida kefyr. Lactic acid bacteria were found to predominate the total microflora of the FTM with their count ranging between 2.0 × 104 cfu/ml to 2.0 × 108 cfu/ml. Microbiological examination revealed that the FTM was safe for consumption as non-LAB counts were below the limit of acceptance which is 2.0 × 105 cfu/ml for dairy milk by Codex Alimentarius Commission. The quantity of lactic acid produced by the LAB isolates ranged between 0.86 g/l - 2.86 g/l while that of hydrogen peroxide ranged between 0.16 g/l - 0.51 g/l. Starter cultures were selected based on predominance of isolate, physiological characteristics, quantity of lactic acid and hydrogen peroxide production. The tiger nut varieties were fermented with the following starter combinations LP, LP/LC, LP/LC/LT, LP/LT while the fifth was spontaneously fermented. The nutritional, chemical and sensory properties of the starter fermented tiger nut milk were evaluated. The highest protein content (24.80%) was obtained in FTM with mixed cultures of LP/LC/LT while the least (3.00%) was obtained in spontaneously fermented milk. There was a significant difference in the FTM varieties. The highest fat content (9.40%) was obtained in spontaneously fermented tiger nut milk while the least (3.40%) was found in FTM with mixed cultures of LP/LC/LT. Fermentation decreased the pH and increased the lactic acid of the starter developed FTM, while sensory evaluation test showed that the FTM with mixed cultures of LP/LC/LT was highly acceptable. In conclusion, an excellent and acceptable FTM can be produced using treatments which comprise of pasteurization at 90°?for 15 minutes, fermentation at 45℃?for 18 hours using mixed cultures of Lactobacillus plantarum, Lactococcus lactis and Lactococcus thermophilus.
文摘Liquid food industries use different preservation methods to extend the shelf life of products by reducing both enzymatic and microorganism activities.Emerging non-thermal pasteurization techniques are applied in order to avoid thermal processes maintaining the microbial safety and quality of liquid foods.Non-thermal preservation technologies used in the liquid food industry include high-pressure processing(HPP),pulsed electric field(PEF),ultraviolet light(UV-C)and ultra-sonication(US).HPP is a method to target specific organisms by applying a pressure range of 100-1,000 MPa.PEF uses short pulses of a strong electric field applied to a flowing liquid food which affects the whole cell membrane of the organism.UV-C treatment at 253.7 nm has been proven to be appropriate for maintaining liquid quality and minimal deterioration of nutrients.US is applied to liquid foods in a lower frequency range of 20-100 kHz and a higher sound intensity of 10-1,000 W/cm2 to the breakdown of cells.According to scientific literature,those methods have been applied to fruit juices like orange,apple,pear,coconut water,etc.Most of the non-thermal methods achieved the Food and Drug Administration(FDA)requirement of a 5-log reduction of microorganisms without deteriorating the sensory and nutritional attributes of fruit juices.Some of these methods have already been commercialized and others are still in a pilot scale.This study gives a comprehensive overview of published literature regarding the potential for using non-thermal pasteurization methods to extend the shelf life of different fruit juices with minimal deterioration of nutritional and sensory quality.
文摘BACKGROUND Breast milk is the primary source of nutrition for newborns.Hospitalized babies frequently need nutritional support from Human Milk Banks.As bacterial species of the genus Enterococcus are part of the microbiota of healthy donors,they may contaminate samples of pumped breast milk.AIM To identify and characterize the bacterial virulence and resistance in samples isolated from the nipple-areolar region,hands,and breast milk aliquots from donors at the Human Milk Bank of Municipal Hospital EsauMatos in the city of Vitória da Conquista,Bahia State,Brazil.METHODS The personal hygiene and sanitation of donors were analyzed with the aim of identifying possible reasons for contamination of pumped milk.Cutaneous samples as well as aliquots of unpasteurized and pasteurized milk from 30 participants were obtained.Each Enterococcus spp.isolate underwent a disk diffusion susceptibility test and molecular biology techniques to determine resistance and virulence genes.RESULTS Enterococcus spp.were identified in 30%of donors(n=9),and 11 specimens were isolated.Resistance to tetracycline was highly prevalent,being detectable in 63%of the isolates(n=7)and followed by intermediate sensitivity to ciprofloxacin,observed in 27%of the specimens(n=3).The efaA gene was found in 63%(n=7)of the isolates,while the ace gene was detected in 27%(n=3).CONCLUSION This study illustrates the importance of microbiological monitoring by Human Milk Banks and the need for alternatives to prevent the presence of Enterococcus spp.in hospital settings.
文摘Background: The present experiment was performed to assess the effects of different sources of milk on the growth performance, serum metabolism, immunity, and intestinal development of calves. Eighty-four Holstein male neonatal calves were assigned to one of the following four treatment groups: those that received bunk tank milk(BTM), untreated waste milk(UWM), pasteurized waste milk(PWM), and acidified waste milk(AWM) for 21 d.Results: Calves in the BTM and AWM groups consumed more starter(P < 0.05) than those in the UWM group.Average daily gain in the UWM group was the highest(P < 0.05). Calves exhibited the highest(P < 0.05) serum total protein, albumin, total cholesterol, high density lipoprotein, triglycerides, growth hormone, immunoglobulin(Ig) A and Ig M concentrations in the UWM group, highest malondialdehyde and tumor necrosis factor-α in the PWM group(P < 0.05), and highest glutathione peroxidase and Ig G in the BTM group(P < 0.05). The jejunum and ileum of the calves in all treatments presented a slight inflammatory response. The jejunal inflammation scores were higher(P < 0.05) in the UWM and AWM groups than the BTM group; the ileal inflammation scores increased more(P < 0.05) in the AWM group than the BTM group. Jejunal immunohistochemical scores(IHS) were higher(P < 0.05) in the PWM and AWM groups than the BTM group. Compared to the other three groups, calves feeding on BTM had lower(P < 0.05) ileal IHS. Jejunal interleukin(IL)-1β, IL-8, and IL-10 mRNA expression in the UWM group was the highest(P < 0.05). Calves fed AWM increased(P < 0.05) mRNA expression of IL-8 and toll like receptor 4(TLR-4) in the jejunum and IL-8, IL-1β, IL-6, IL-8, and IL-10 in the mesenteric lymph nodes.Conclusions: Overall, bunk tank milk is the best choice for calf raising compared to waste milk. The efficiency of feeding pasteurized and acidified waste milk are comparable, and the acidification of waste milk is an acceptable labor-saving and diarrhea-preventing feed for young calves.
文摘Objective:To determine the presence and levels of microbes in unexpired pasteurized milk from randomly selected supermarkets in Kingston,Jamaica.Methods:The quantitative study used a stratified random sampling technique in the selection of the 20 representative milk samples from six(6) supermarkets.Microbiological tests such as methylene blue reduction,standard plate count(SPC),coliform plate count(CPC),purity plate culture,gram staining and biochemical tests were performed to examine the microbes in purchased unexpired pasteurized milk.Results:One sample(BCr016) had a pH of 4.0.a rancid odour and curdled appearance.It decolourized within one hour during the methylene blue reduction test and was classified as class 4 milk.Seven of the samples were sterile with no microbe growth on the plate count agar and violet red bile salt agar(VRBA).The milk samples that appeared to be safe for consumption were all 10,11,12 and 13 days before expiration.The VRBA sample BCr016,had a colony count of 13 400 CFU/ mL.There was the presence of Escherichia coli in sample LCr021 which had a standard plate count of 1 580 SPC/mL and a coliform count of 500 CFU/mL.Enterobacter sp.was present in colonies from BCr016 and all the other milk samples.Conclusions:Unacceptable levels of Entembacter spp.and Escherichia coli were found in most of the samples.Effective measures to ensure safe milk for human consumption such as the phosphatase test and methylene blue reduction test should be routinely performed on each batch of milk processed by dairy plants.
文摘Differentiating pasteurized milk and reconsti-tuted milk by scientific approach was necessary to defend consumer from economic fraud of wrong labeling. In this paper 2DGE (2 Dimen-sional Gel Electrophoresis)-coomassie brilliant blue staining method was employed and sig-nificant color intensity changing was observed among raw milk, pasteurized milk, UHT milk and reconstituted milk. For example, the intensity of 10 protein spots including casein and lac-toglobulin reduced more than two folds from pasteurized milk to reconstituted milk. However, DIGE (Differential Gel Electrophoresis) assay showed that the majority protein remained simi-lar level from pasteurized milk to reconstituted milk. Therefore the color fading of coomassie brilliant blue stained 2D gels may be due to other biochemical reaction, such as Maillard reaction, instead of protein degradation. Stability of 2DGE pattern was confirmed by running six gels of the same sample in parallel and software analysis showed that all proteins were at similar level. Two commercialized pasteurized milk samples and one reconstituted milk sample were tested by 2DGE-coomassie blue staining method and re-constituted milk could be easily identified.
基金supported by the National Natural Science Foundation of China(31871831,32172279)Liaoning Provincial Natural Science Foundation regional Joint Fund project(2020-MZLH-34)+1 种基金Shenyang City Youth Science and Technology Innovation Leading Talent Project(RC200495)Shenyang Science and technology innovation platform project(21-103-0-14,21-104-0-28).
文摘Pasteurized milk contains complex microbial communities affected by sterilization and storage conditions.This complex microflora may be the possible reason that pasteurized dairy products are highly prone to spoilage.In this study,packaged pasteurized milk products collected from dairy processing factories in China were stored at 0,4,10,15,and 25℃ for 0−15 days and subjected to microbial identification using high-throughput sequencing.Accordingly,6 phyla and 44 genera were identified as the dominant microbiota.Moreover,the changes in nutritional composition of the pasteurized milk,including in 16 free amino acids,7 taste values,and 8 chemical constituents,were analyzed using principal component and multi-factor analyses.The Pearson correlation analysis identified Pseudomonas,Aeromonas,Paenibacillus,and Serratia genera as the core functional microbiota that significantly affects the nutritional composition of pasteurized milk.Hence,the results provide a comprehensive understanding of the safety and shelf-life of stored pasteurized milk.
