Evaluating Kombucha and Fruit Juice Blends for a 5-Log Reduction of Acid-Adapted Escherichia coli O157

This study examined the survival of acid-adapted E. coli O157 in kombucha during fermentation and refrigerated kombucha mixed with fruit juices. Acidic and non-acidic kombucha mixes were fermented at 25°C using a commercially available starter culture and inoculated with a 5-strain mixture of acid-adapted E. coli O157. There was >5-log reduction in the pathogen count for both starter mixes within 7 days of fermentation. For the kombucha-juice blends at refrigerated temperature, 14 ml of lemon, apple, orange, and mango juices were mixed with 186 ml kombucha separately. The treatments were inoculated with a 5-strain mixture of acid-adapted E. coli O157 and incubated at 5°C for 14 days. >5-log reduction in the pathogen count was observed in lemon, control, and mango juice blend after 1, 3, and 14 days, respectively. The total reduction in pathogen count in the apple and orange juice blend after 14 days was 4.43 and 4.12 log CFU/ml, respectively. The inability of the kombucha fruit blend to cause a 5-log reduction of E. coli O157 suggests the need for following strict hygienic and good sanitation practices during blending and bottling for home fermenters and an approved HACCP plan for foodservice operators to ensure product safety.

Antioxidant Activities of Okra Protein Concentrate and Isolate after Enzymatic Hydrolysis

Three different proteolytic enzymes (pepsin, trypsin and papain) were used to prepare okra seed protein concentrate and okra seed protein isolate hydrolysates. The hydrolysates were assayed for antioxidant properties using radical scavenging, reducing power and metal chelating assays. The highest degree of hydrolysis (after 360 min) for okra protein isolates was 35.20%, 35.21% and 10.53% for pepsin, papain and trypsin respectively. The highest degree of hydrolysis (after 360 min) for okra protein concentrates was 26.8%, 28.59% and 6.47% for pepsin, papain and trypsin respectively. Pepsin hydrolysates showed higher metal chelating activity and radical scavenging activity than trypsin and papain hydrolysates. Trypsin hydrolysates showed the lowest antioxidant activities, which may be due to the low degree of hydrolysis. In general, for antioxidant activity, there was an increase in activity with an increase in the degree of hydrolysis. Similar antioxidant activity was found in both the okra protein isolate and concentrate hydrolysates except for metal chelating activity which was higher in okra protein isolate hydrolysates. This may be due to the higher ash concentration in the concentrates (9.4% in concentrates vs. 2.6% in isolates). In this study, pepsin hydrolysates with a final DH of 35.2% showed higher reducing power and metal chelating activity than trypsin and papain hydrolysates. Okra protein hydrolysates were found to have varying levels of antioxidant activity, which was dependent on the specificity of the protease and proportional to the degree of hydrolysis achieved.

Fit “n” Cool Kids: Effects of Peer-Modeling and Goal Setting on Physical Activity

Background: Decreasing the risk of overweight and obesity from an early age is imperative and efforts should focus on fostering children’s physical activity (PA). Within school-based interventions, there is insufficient evidence on the effectiveness of the use of character peer-modeling and goal setting to increase physical activity. Therefore, the purpose of this study was to examine the impact of a school-based intervention on PA and enjoyment of PA in grades 3 - 5 elementary school age children at two urban elementary schools. Methods: Participants were 95 students of 8 - 10 years old;activity monitors were used to assess physical activity. Daily physical activity and enjoyment was recorded at baseline, intervention, and at a 6-school-week follow-up. Results: PA significantly increased in the intervention school averaging 5549 steps at baseline, 5889 steps during the intervention, and 6515 during follow-up (p Conclusion: The Fit “n” Cool Kids intervention presents the potential of peer-modeling and goal setting for increasing PA at school. Continued interventions in schools may positively influence children’s healthy living patterns.

High Prevalence of Suboptimal Child-Feeding Practices and Child Morbidity among Families from Low Socio-Economic Urban Areas in Harare

Introduction:Optimal breastfeeding and complementary feeding have been proven to reduce malnutrition.Declining socio-economic environment is associated with poor feeding practices,high morbidity,and risk of malnutrition among children from urban poor families.Objective:The aim of this cross-sectional study was to assess child-feeding practices and morbidity prevalence among Harare urban-families living in low socio-economic areas.Methods:A health-facility based cross-sectional study was conducted in five clinics of Harare serving low socio-economic communities between July and August 2014.A structured interviewer-administered questionnaire assessing child-feeding practices was used to interview primary caregivers.Prevalence of diarrhea,influenza,malaria,measles,fever,and cough was assessed.Data were analysed using SPSS v21.Results:A total of 218 mother-child pairs attending growth monitoring were enrolled in the study:Seventy-five percent of the children were below two years;early introduction of solid foods(before six months)was observed in 81.4%of the children.Forty-nine percent of young children were fed at least four meals per day and 74%had been weaned onto family meals;Twenty-four percent of the children had diarrhea,59%influenza,1%malaria,1%measles,23%fever and 53%cough in the month preceding the survey.Conclusion:There is a high prevalence of suboptimal feeding practices and morbidity in low socio-economic urban communities of Harare.There is need to design child-feeding interventions for the urban community targeting all family members involved in decision-making.

Characterization of Lipases from Geobacillus stearothermophilus and Anoxybacillus flavithermuscell Lysates

The aim of this study was to characterize lipases from two thermophilic bacteria, Geobacillus stearothermophilus (GS) and Anoxybacillus flavithermus (AF) in heat treated cell lysates. The pH optimum, pH stability, temperature stability and substrate kinetics and specificity of the lipases were determined. Optimum activity of the lipase from GS (LGS) was observed at pH 7.5, and the optimum activity of the lipase from AF (LAF) was at pH 8.0. LGS was stable up to 70°C after 12 hrs while LAF was stable up to 90°C after 12 hrs. Both enzymes were stable at a pH range of 6 to 8 over 12 h at 4°C. LGS had a highest Vmax value of 22 mM·min-1·mg-1 with p-nitrophenyl acetate while the lowest Km was 0.8 mM with p-nitrophenyl laurate. The highest Vmax of LAF was 2.5 mM·min-1·mg-1 with p-nitrophenyl myristate, and the lowest Km was 0.4 mM with p-nitrophenyl octanoate. LGS preferentially hydrolyzed p-nitrophenyl acetate and p-nitrophenyl octanoate while LAF preferentially hydrolyzed p-nitrophenyl myristate and p-nitrophenyldodecanoate. Lipases from both GS and AF showed characteristics that would be beneficial in food processing.

Optimization of Culture Conditions to Produce Phytase from <i>Aspergillus tubingensis SKA</i>

The effects of nutrients and physical conditions on phytase production were investigated with a recently isolated strain of Aspergillus tubingensis SKA under solid state fermentation on wheat bran. The nutrient factors investigated included carbon source, nitrogen source, phosphate source and concentration, metal ions (salts) and the physical parameters investigated included inoculum size, pH, temperature and fermentation duration. Our investigations revealed that optimal productivity of phytase was achieved using wheat bran supplemented with: 1.5% glucose. 0.5% (NH4)2SO4, 0.1% sodium phytate. Additionally, optimal physical conditions were 1 × 105 spore/g substrate, initial pH of 5.0, temperature of fermentation 30°C and fermentation duration of 96 h. Overall, a 34% improvement in phytase activity was achieved by using the optimal conditions.