Effects of Post-harvest Treatments on the Microbiological Quality and Pesticide Residues of Lowbush Blueberries

Lowbush blueberries of the species Vaccinium angustifohm are native to the Northeast United States. In the state of Maine, lowbush blueberries are commercially managed and harvested each year to be marketed as either IQF (individually quick fiozen) or fiesh pack. Since IQF berries are processed at the field level, post-harvest treatments must be effective in ensuring crop quality and safety. Furthermore, with the increase in concern for microbiological and chemical food safety, post-harvest treatment of lowbush blueberries must be effective in reducing microbial populations and pesticide residues. Currently, the Maine Wild Blueberry Industry incorporates a 50-100ppm chlorinated water spray into the processing of lowbush blueberries. However, the possibility of fbture regulatory constraints on the use of chlorine as a sanitizer calls for investigation of alternative treatments that would be equally effective in improving microbial quality and safety. This thesis examined the influence of post-harvest treatments namely chlorine, hydrogen peroxide, citric acid, and distilled water on the microbiological quality and residual phosmet levels of lowbush blueberries. This research also assessed the degradation of phosmet on commercial blueberries in Maine. Field samples were collected fiom one of Maine\u27s commercial blueberry fields immediately after treatment with aerial sprays of Imidan 70-W (phosmet). Sampling continued for a total of five weeks during the summer of 2001. Berries were subjected to 500mL sprays of lOOppm chlorine, 0.5% hydrogen peroxide, 0.5% citric acid, or distilled water. Microbiological analysis of total aerobes, yeast, and mold were conducted using FDA Standard Methods. Residual phosrnet was measured by GCIMSD. Microbial reductions of up to 1.5 log were observed on individual washed samples. Significant differences (pc0.05) in antimicrobial effectiveness existed among treatments allowed the same contact time. Overall, samples treated with lOOppm chlorine had the lowest mean counts of total aerobes, yeast, and mold. No significant differences (px0.05) were observed in treatment effectiveness after holding for 30 seconds versus 300 seconds. During the five weeks pre-harvest, results showed that as the microbial load increased, residual phosmet levels decreased. Residual phosmet levels of treated samples were significantly lower (p\u3c0.05) than residues on unwashed berries. The extent to which treatments removed residual phosmet was influenced by the week of sampling. The greatest reductions in residual levels were observed on blueberries treated during the first three weeks when residual levels on unwashed controls were highest. Although treatments were less effective during the final weeks of the study, the residual phosmet levels on the control samples fell below the EPA tolerance level of 10,000ppb. Furthermore, 100% of all blueberries sampled during the final three weeks of the study contained residual phosmet at levels below the EPA tolerance. Results of this study demonstrate the efficacy of treating lowbush blueberries with 100ppm chlorine sprays to improve the microbiological quality and safety of the crop; however, additional research on alternative sanitizers and their effective concentrations should be conducted to aid the industry should the use of chlorine be restricted

Effect of Acute Ingestion of Green Tea Extract and Lemon Juice on Oxidative Stress and Lipid Profile in Pigs Fed a High-Fat Diet.

Green tea and its catechins have been shown to ameliorate high fat diet-induced oxidative stress and hyperlipidemia. However, low bioavailability of catechins limits their therapeutic potential. Lemon juice (LJ) has been suggested to enhance the bioavailability of catechins in vitro. This study investigated the antioxidative and hypolipidemic efficacy of a single dose of green tea extract (GTE) or GTE plus LJ (GTE + LJ) in high-fat diet fed pigs. Sixteen pigs ingested a single dose of GTE (190 mg/kg/day) or GTE + LJ (0.75 mL/kg/day) mixed with low-fat (LF; 5% fat) or high-fat (HF; 22% fat) diets and blood samples were collected for 24 h. Plasma catechin level peaked at two hours, and gradually returned to baseline after six hours following the intake. The addition of LJ significantly increased plasma catechin level. The diet containing GTE did not lower plasma cholesterol and triacylglycerol (TG) concentrations, superoxide dismutase (SOD) and catalase activity, or malondialdehyde concentration in 24 h in HF-fed pigs. Addition of a single dose of LJ, however, significantly decreased plasma TG level in LF groups but did not cause further changes on any other markers compared to the GTE alone. Our findings indicate limited effect of a single meal containing GTE on plasma antioxidant enzymes, lipid profile, and lipid peroxidation in pigs and no significant synergistic/additive action of adding LJ to GTE within 24 h in pigs. A study with a longer treatment period is warranted to further understand the potential role of GTE in reducing HF diet-induced oxidative stress and the possible synergistic role of LJ

2002 Wild Blueberry Project Reports

The 2002 edition of the Wild Blueberry Project Reports was prepared for the Wild Blueberry Commission of Maine and the Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include: 1. Factors Affecting Microbial and Pesticide Residue Levels on Wild Blueberries 2. Effect of Blueberry Products on Oxidation in Meat Based Food 3. Determination of Pesticide Residue Levels in Freshly Harvested and Processed Wild Blueberries 4. Detection of Infested Wild Blueberries using Near-Infrared Spectroscopy 5. Investigation Of The Mechanism By Which Blueberry Fractions Maintain Arterial Integrity 6. Antioxidant Assessment in the Elderly 7. Water Use of Wild Blueberries and the Impact of Plant Water Stress on Yield 8. Control Tactics for Wild blueberry Pest Insects 9. IPM Strategies 10. Pest Biology 11. Wild Blueberry Pollination Research 12. Survey and Determination of Effective Control of Stem Blight and Leaf Spot Diseases in Wild Blueberry Fields 13. Effect of Foliar-applied Iron Chelate Concentration on Leaf Iron Concentration, Wild Blueberry Growth and Yield 14. Effect of Boron Application Methods on Boron Uptake in Wild Blueberries 15. Effect of Foliar N spray on Leaf N Concentration, Growth and Yield of Wild Blueberries 16. Effect of Foliar Spray (4-13-15) on Leaf Nutrient Concentration, Growth and Yield of Wild Blueberries 17. Effect of Foliar Copper Application on Growth and Yield of Wild Blueberries 18. Effect of Foliar Copper and/or Iron Application on Growth and Yield of Wild Blueberries 19. Effect of Soil pH on Nutrient Uptake 20. Assessment of Hexazinone Alternatives for Weed Control in Wild Blueberries and Weed Control 21. Evaluation of Fall Applications of Sulfonylurea Herbicides for Bunchberry Control in Wild Blueberries 22. Evaluation and Demonstration of Techniques for Filling in Bare Spots in Wild Blueberry Fields 23. Blueberry Extension Education Program Base 24. 2002 Pesticide Groundwater Survey 25. Cultural Weed Management using sulfur to lower the p

2005 Wild Blueberry Project Reports

The 2005 edition of the Wild Blueberry Project Reports was prepared for the Wild Blueberry Commission of Maine and the Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include: 1. Evaluation of Emerging Disinfections Technologies for Wild Blueberry Processing 1A. Incorporation of wild blueberry puree into a soy-based burger and its effect on sensory and chemical properties of the broiled burgers. 2. Incorporation of wild blueberry puree into a soy-based burger and its effect on sensory and chemical properties of the broiled burgers 3. Wild blueberries and Arterial Functional Properties 4. Practical Microbial Control Approach and Antimicrobial Properties Study for Wild Blueberries 5. Wild Blueberries Reduce Risks for Cardiovascular Disease –No Report at this time, data is still under analysis. 6. Irrigation Water Use in Wild Blueberry Production 7. Control Tactics for Blueberry Pest Insects, 2005 8. Integrated Pest Management (IPM) strategies, 2005 9. Control Tactics for Blueberry Pest Insects, 2005 10. The Effect of Fungicides and Cultural Treatments on Monilinia Blight, Yield and Post-Harvest Disease in Wild Blueberries 11. Effect of Soil pH on Nutrient Uptake 12. Effect of Manganese on Growth and Yield of Wild Blueberry 13. Raising Foliar Nitrogen by Application of CoRoN 14. Effects of Summer Foliar Fertilization to Increase Branch Length and Flower Bud Formation in the Prune Year 15. Assessment of Hexazinone Alternatives for Weed Control in Wild Blueberries and Field Cover Program Base 16. Evaluation of Fall Applications of Tribenuron Methyl for Bunchberry Control in Wild Blueberries 17. Evaluation of spot treatments of Tribenuron Methyl for weed control in Wild Blueberries 18. Evaluation and Demonstration of Techniques for Filling in Bare Spots in Wild Blueberry Fields 19. Assessment of Evitol and Kerb for Sedge Control in Wild Blueberrie

2004 Wild Blueberry Project Progress Reports

The 2004 edition of the Wild Blueberry Project Progress Reports was prepared for the Wild Blueberry Commission of Maine and the Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include: 1. Determination of Pesticide Residue Levels in Freshly Harvested and Processed Lowbush Blueberries 2. Effect of Wild Blueberry Products on Physical, Chemical, Microbiological and Sensory Quality of Soy-Based and Ground Beef Patties 3. Evaluation of Emerging Disinfection Technologies for Wild Blueberry Processing 4. Detection of Infested Blueberries using Near-Infrared Spectroscopy-Spectra Collection 5. Health Claims for Wild Blueberries 6. Wild blueberries and Arterial Functional Properties 7. Irrigation Water Use in Wild Blueberry Production 8. Insect Control Tactics for Blueberry Pest Insects & Program Base 9. Integrated Pest Management (IPM) Strategies 10. Biology and Ecology of Blueberry Insect Pests 11. Stem Blight/Dieback and Leaf Spot Diseases in Lowbush Blueberry Fields 12. . Evaluation of fungicide control of mummy berry blight in wild blueberries: a) ground application and b) aerial application 13. Effect of Foliar Copper Application on Growth and Yield of Wild Blueberries 14. Effect of Soil pH on Nutrient Uptake 15. Effect of Fertilizer Timing (prune year vs. crop year) on Wild Blueberry Growth and Productivity 16. Raising Foliar Nitrogen by Application of CoRoN 17. Effect of Manganese on Growth and Yield of Wild Blueberry 18. Assessment of Hexazinone Alternatives for Weed Control in Wild Blueberries and Field Cover Program Base 19. Evaluation of Fall Applications of Sulfonylurea Herbicides for Bunchberry Control in Wild Blueberries 20. Evaluation and Demonstration of Techniques for Filling in Bare Spots in Wild Blueberry Fields 21. Assessment of Evitol for Sedge Control in Wild Blueberries 22. Cultural Weed Management Using pH 23. 2004 Pesticide Groundwater Survey 24. Wild Blueberry Extension Education Program in 200

2003 Wild Blueberry Project Reports

The 2003 edition of the Wild Blueberry Project Reports was prepared for the Wild Blueberry Commission of Maine and the Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include: 1. Factors Affecting the Microbial and Pesticide Residues Levels on Lowbush Blueberries 2. Effect of Blueberry Products on Oxidation in Ground Beef Patties 3. Infestation Detection using Near-Infrared Spectroscopy 4. Whole Wild Blueberries and Arterial Functional Properties 5. Irrigation Water use in Wild Blueberry Production 7. Control Tactics for Blueberry Pest Insects 8. IPM Strategies 9. Biology and Ecology of Blueberry Pest Insects, 2003 10. Wild Blueberry Pollination Research 11. Stem Blight/Dieback and Leaf Spot Diseases in Wild Blueberry Fields 12. Effect of Foliar N spray on Leaf N Concentration, Growth and Yield of Wild Blueberries 13. Effect of Foliar Spray (4-13-15) on Leaf Nutrient Concentration, Growth and Yield of Wild Blueberries 14. Effect of Foliar Copper Application on Growth and Yield of Wild Blueberries 15. Effect of Foliar Copper and/or Iron Application on Growth and Yield of Wild Blueberries 16. Effect of Soil pH on Nutrient Uptake. 17. Effect of Gibberellic Acid (GA3) and CPPU on Fruit Set and Yield of Wild Blueberry after low temperature flower stress 18. Effect of Fertilizer Timing (prune year vs. crop year) on Wild Blueberry Growth and Productivity. 19. Assessment of Hexazinone Alternatives for Weed Control in Wild Blueberries and Weed Control and Field Cover Program Base 20. Evaluation of Fall Applications of Sulfonylurea Herbicides for Bunchberry Control in Wild Blueberries 21. Assessment of clean-cut adapter on hand clippers for weed control in wild blueberries 22. Evaluation and Demonstration of Techniques for Filling in Bare Spots in Wild Blueberry Fields 23. Blueberry Extension Education Program in 2003 24. 2003 Pesticide Groundwater Survey 25. Cultural Weed Management using Sulfur to lower the p

2006 Lowbush Blueberry Project Reports

The 2006 edition of the Lowbush Blueberry Project Reports was prepared for the Wild Blueberry Commission of Maine and the Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include: 1. Evaluation of Emerging Disinfection Technologies for Wild Blueberry Processing 2. Incorporation of wild blueberry puree into a soy-based burger and its effect on sensory and chemical properties of the broiled burgers 3. Infestation Detection using NIRS 4. Mechanism of Action through which Wild Blueberries affect Arterial Functional Properties in Normotensive and Spontaneously Hypertensive Rats 5. Practical Microbial Control Approach for Wild Blueberries and their Antimicrobial Property 6. Wild Blueberry Consumption and Risks for Cardiovascular Disease 7. Irrigation Water use in Wild Blueberry Production 8. Control Tactics for Blueberry Pest Insects & Program Base 9. Integrated Pest Management (IPM) Strategies 10. Biology and Ecology of Blueberry Insect Pests, 2006 11. Research on Wild Blueberry Diseases for 2006-2007 12. Effect of Soil pH on Nutrient Uptake 13. Effect of Manganese on Growth and Yield of Wild Blueberry 14. Effects of Summer Foliar Fertilization to Increase Branch Length and Flower Bud Formation in the Prune Year 15. Effects of Phosphite Foliar Fertilizers on disease control and fruit set of wild blueberry 16. Assessment of Hexazinone Alternatives for Weed Control in Wild Blueberries 17. Evaluation of Fall Applications of Tribenuron Methyl for Bunchberry Control in Wild Blueberries 18. Evaluation of spot treatments of Tribenuron Methyl, Ultim and Roundup for weed control in Wild Blueberries 19. Blueberry Extension Education Program 20. Cultural Weed Management Using p

2001 Wild Blueberry CSREES Project Reports

The 2001 edition of the Wild Blueberry CSREES Progress Reports was prepared for the Maine Wild Blueberry Commission and the University of Maine Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include: 1. Effect of Wild Blueberry Products on Oxidation in Meat Based Food Systems 2. Factors Affecting the Microbial and Pesticide Residues Levels on Wild Blueberries 3. Determination of Pesticide Residue Levels in Fresh and Processed Wild Blueberries 4. Separation of Maggot-Infested Wild Blueberries in the IQF Processing Line 5. Water Use of Wild Blueberries and the Impact of Plant Water Stress on Yields 6. Survey of Stem Blight and Leaf Spot Diseases in Wild Blueberry Fields 7. IPM Strategies 8. Control Tactics for Wild Blueberry Pest Insects, 2001 9. Biology and Ecology of Blueberry Pest Insects 10. Diurnal Bee Activity and Measurement of Honeybee Field Strength 11. Effect of Foliar-applied Iron (Fe) Chelate Concentration on Leaf Iron Concentration, Wild Blueberry Growth and Yield 12. Effect of Boron Application Methods on Boron Uptake in Wild Blueberries 13. Effect of Foliar Iron and Copper Application on Growth and Yield of Wild Blueberries 14. Effect of Fertilizer Timing on Wild Blueberry Growth and Productivity 15. Effect of Foliar Copper Application on Growth and Yield of Wild Blueberries 16. Effect of Prune-year Applications of Nutri-Phitetm P or Nutri-Phitetm P+K on Growth and Yield of Wild Blueberry (Vaccinium angustifolium Ait.) 17. Effect of Soil pH on Nutrient Uptake 18. Assessment of Azafenidin for Weed Control in Wild Blueberries 19. Assessment of Rimsulfuron for Weed Control in Wild Blueberries 20. Assessment of Pendimethalin for Weed Control in Wild Blueberries 21. Evaluation and Demonstration of Techniques for Filling in Bare Spots in Wild Blueberry Fields 22. Assessment of Sprout-less Weeder for Hardwood Control in Wild Blueberries 23. Wild Blueberry Extension Education Program in 2001 24. Evaluation of Fungicide Efficacy in Wild Blueberry Fields 25. 2001 Pesticide Groundwater Survey 26. Cultural Weed Management Using Sulfur to Lower the pH 27. Wild Blueberry Web Sit

Evaluation of Chemical and Photochemical Oxidation Processes for Postharvest Processing of Lowbush Blueberries (\u3cem\u3eVaccinium angustifolium\u3c/em\u3e)

Lowbush blueberries (Vaccinium angustifolium) indigenous to the state of Maine are commercially processed prior to freezing and marketing as an IQF (individually quick frozen) product. Chlorinated water sprays are typically relied upon to improve the microbiological quality of blueberries; however, chlorine-alternatives are receiving increased attention for application in post-harvest processing due to the limited effectiveness of chlorine and public health and environmental concerns over toxic byproduct production. The primary objectives of this research were to isolate and identify predominant bacterial flora on lowbush blueberries, to comparatively evaluate the antimicrobial effectiveness and pesticide degradation capacity of single treatment methods (H2O2, UV, Cl2, O3) versus advanced oxidation processes (AOPs) (H2O2/UV, Cl2/UV, O3/H2O2/UV), and to determine the effects of these oxidation treatments on quality parameters such as anthocyanin content and blueberry color. In addition to these objectives, the predominant bacterial species isolated from lowbush blueberries were evaluated for their role in enhanced biodegradation of phosmet on blueberries and in aqueous media supplemented with phosmet. Enterobacter agglomerans and Pseudomonas fluorescens were the most frequently isolated bacteria on lowbush blueberries. In comparison of single processes versus AOPs, 1% hydrogen peroxide and 1 ppm ozone yielded dynamic reductions in the population of common spoilage bacteria while maintaining the quality of lowbush blueberries. Improvement in chemical safety of blueberries was achieved by application of UV or aqueous ozone which resulted in reduction in phosmet residues without inducing oxidation of phosmet to phosmet oxon. Compared to the current industry standard, ozone represents the most efficacious, environmentally-benign post-harvest treatment capable of improving the microbial quality and chemical safety of Maine wild blueberries without negatively affecting the quality as defined by anthocyanin content and pigment retention. Isolates of E. agglomerans and P. fluorescens proved capable of degrading phosmet on blueberry fruit and in aqueous systems through substrate utilization as a carbon source. Microbial mineralization lessened the toxicity of residues by degrading phosmet to secondary and tertiary metabolites. According to experimental results, mineralization by these isolates represents an active metabolic pathway for phosmet degradation pre- and post-harvest which is critical to understanding the environmental synergy between blueberries and indigenous microflora