Listeria monocytogenes, a ubiquitous foodborne pathogen, was recognized over 70 years ago. It is the source of the human disease listeriosis. The majority of Listeria monocytogenes that have been isolated from food product or human cases are of the serotypes ½ a, ½ b and 4b. Due to the recent outbreaks, recalls and deaths associated with Listeria monocytogenes in ready-to-eat meat products, the United States Department of Agriculture (USDA), Food Safety and Inspection Service (FSIS) on October 2, 2003 issued a directive for the control of Listeria monocytogenes on ready-to-eat products. The ready-to-eat food industry must impose a post-lethality treatment and/or growth inhibitor for Listeria monocytogenes on ready-to-eat products. The purpose of this study was to assess the use of different antimicrobial treatments for the inhibition of Listeria monocytogenes on the surface of food products. The utilization of natural ingredients such as cranberries as well as chemicals such as acidified sodium chlorite was employed. An edible film made of chitosan that was dissolved in acetic acid and lactic acid was also evaluated. The survival of Listeria monocytogenes at freezer temperatures on a variety of ready-to-eat meat products was also assessed. Our study has been successful in understanding the survival of Listeria monocytogenes at freezer temperatures on the surface of ready-to-eat meat products under vacuum and non-vacuum package storage conditions. It has also been observed that the use of cranberry juice, acidified sodium chlorite, and chitosan have great potential antimicrobial properties that can be employed by food processors.

The Catfish industry faces a problem of off-flavors due to odorous compounds produced by cyanobacteria and blue-green algae. Beta-Cyclocitral imparts a hay-woody odor to pond water and fish tissues. At present there are no reliable pond treatment methods available to control these off-flavors. To monitor the levels of this compound for quality control, rapid, sensitive and inexpensive methods are needed. The major goal of this study was to develop enzyme-linked immunoflow assays based on monoclonal and polyclonal antibodies that are specific and sensitive enough to detect beta-cyclocitral in catfish pond water. Beta-Cyclocitral-PPD conjugate was prepared and used to immunize two chickens and two mice for the production of polyclonal and monoclonal antibodies against beta-cyclocitral respectively. Monospecific polyclonal antibodies were purified from the eggs laid by the immunized chickens, using affinity chromatography. For the production of the monoclonal antibodies, hybridoma cells were made by fusion of myeloma cells and spleen cells of the mice that showed high antibody titer and specificity. Hybridoma cells that secreted high affinity monoclonal antibodies were cloned by the limiting dilution method and at least 10 hybridoma cell lines positive for anti-beta-cyclocitral antibodies were established. Immunochemical methods based on anti-beta-cyclocitral IgY and IgG were developed. The two ELISAs based on IgY and IgG had a limit of detection of 1.0 ng/mL and respective I50 values of 3.93 and 7.98 ng/mL. Two enzyme-linked-immunoflow (ELIFA) assays were developed based on the ELISAs. The ELIFAs were very easy to perform but were less sensitive than the ELISAs as shown by their I50 of 46 ug/mL for the IgY-based ELIFA and 93 ug/mL for the IgG-based ELIFA. Further investigations are required for the more efficient recovery of the monoclonal antibodies, to validate the ELISAs, to improve the sensitivity of the ELIFAs and to determine the potential to adapt the developed assays to a kit format for use by the catfish industry and water treatment industries as well as other aquaculture industries.

Day care center reports from the Louisiana Board of Health Sanitarians were generated from day care centers participating in the Child and Adult Care Food Program (CACFP) in the state of Louisiana. The types of violations reported included temperature abuse, lack of handwashing supplies, spoiled food, incorrect dishwashing procedures, and physical plant problems. A survey was developed and mailed to all 50 state CACFP Directors requesting information on the sanitary violations reported by their state sanitarians for day care centers participating in CACFP. The violations cited by the individual state CACFP Directors were similar to those reported by the Louisiana Board of Health Sanitarian Reports. Louisiana State day care directors participating in the CACFP were surveyed twice to determine their knowledge of sanitation principles food handling, once prior to a food safety training workshop and then after the training. The two survey responses were similar with the exception of three of the questions. A food safety manual was developed using basic sanitation and HACCP principles. It was presented as a food safety workshop for Louisiana CACFP Day Care Directors. The manual will be distributed to all CACFP participants as part of their training material for participation.

Listeria monocytogenes has been recognized as a human pathogen since 1929. This pathogen is found in many foods and listeriosis infections affect approximately 2,500 people in the United States each year, according to the Centers for Disease Control and Prevention. Of those infected with L. monocytogenes approximately 500 die as a result of the illness. Listeria monocytogenes is a bacterium, commonly found in water, soil, plant material, animals and human. Today, different methods are used by food manufacturers, to reduce the risk of Listeria monocytogenes, such as antimicrobial agents, heating, irradiation, and fermentation. The ability of the bacteria to grow at temperatures as low as 3°C permits multiplication in refrigerated foods. The purpose of this study was to determine the antimicrobial effect of copper ions against Listeria monocytogenes on the surface of copper, brass and concrete coated with polyurethane containing different concentrations of copper ions. The utilization of pH, nutrients and temperatures were applied. Copper alloys antimicrobial effect in two different crawfish processing plants was also evaluated. The amount of copper ions released into raw and cooked shrimp at different temperatures was also assessed. Our study has been successful in understanding the survival of Listeria monocytogenes at different copper ions concentrations under different temperatures, pH and nutrients. It has also been observed that the use of different copper ions concentrations haves great potential as antimicrobial agents that can be employed by food processors.

Red Chile peppers (Capsicum spp.) have become one of the fastest growing spices in U.S. market due to the changing American diet, increasing ethnic diversity and the influence of ethnic foods. Louisiana has long been known for its famous hot sauce production especially sauces that are made from Tabasco pepper (C. frutescens). The raw peppers are normally ground together with salt and fermented before production. Peppers mash is usually fermented in wood barrel made out of oak. However, a wood barrel is very expensive when used in pepper fermentation. As compared to wood barrel, plastic barrel have longer usage time and better sanitation. Understanding the chemical breakdown process involved in fermentation may assist in the development of better quality sauce, improve production sanitation, and reduce the manufacturing cost. The main objective of this study was to evaluate physicochemical properties of Tabasco pepper(C. frutescens) during a two-year fermentation period as affected by the aging material including wooden barrels and plastic barrels. Physicochemical properties like dry weight, pH, titratable acidity, capsaicin level, and sugar level was investigated in a two-year red Tabasco pepper (C. frutescens) fermentation process. Dry weight, pH, and titratable acidity (TA) were measured using standard AOAC procedure. Capsaicin, dihydrocapsaicin, fructose, sucrose, and glucose were analyzed using HPLC method. The soluble uronide that diffused into solution was determined as uronic acid equivalents by the hydroxybiphenyl method using galacturonic acids as standard. Total uronide content and pectin solubility in chelator was determined in air-dried tissues. The degree of depolymerization of CDTA soluble pectin from air-dried tissues was determined by size exclusion gel chromatography. Dry weight of pepper mash significantly decreased during fermentation. Titratable acidity increased due to lactic acid production which lead to decreased in pH. After fermentation, pepper mash still contained residual sugar. Fermentation process did not affect the capsaicinoids concentration. In this study, pepper mash fermented in plastic and oak wood barrel did not show any significant differences in pH, titratable acidity, sugar level, total uronide concentration, pectin degradation, and capsaicin level. Plastic barrels might be an alternative to wood barrels.

Listeria monocytogenes has emerged as a major foodborne pathogen for the seafood industry due to its psychrotrophic nature and its ubiquitous presence. It has been isolated from soil, sewage, dead vegetative matter, aquatic environments, fecal material, fish, crustaceans, and domesticated animals. As a result, L. monocytogenes has been responsible for several shrimp recalls and has been epidemiologically linked to human listeriosis. Fresh seafood products are highly perishable and their shelf-life is limited by microbiological spoilage. Therefore, when pathogenic microorganisms are involved, it poses a health threat to the general public. The situation is further complicated because seafood processing plants are ideal environments for this organism to proliferate. As a result, this creates an ever growing potential for food safety issues. Cetylpyridinium chloride (CPC) has been shown to have antimicrobial effects in decontaminating raw produce and poultry. Therefore, the objective of this study was to determine the effectiveness of cetylpyridinium chloride as a washing solution to inhibit L. monocytogenes growth on the surface of shrimp. Our studies have successfully shown the potential of cetylpyridinium chloride as a washing solution to reduce L. monocytogenes counts on the surface of raw and cooked shrimp stored at 4°C and -20°C. However, further investigations are necessary to determine its impact on sensory properties of shrimp as well as determining CPC residuals on the surface of raw and cooked shrimp. To date, the use of CPC has only been approved by the FDA at a level not to exceed 0.3 grams of CPC and should also contain propylene glycol at a concentration of 1.5 times that of the CPC per pound of raw poultry carcass.

Vibrio vulnificus and Vibrio parahaemolyticus are gram-negative halophilic bacteria found in the natural aquatic environment. V. vulnifcus and V. parahaemolyticus have been implicated in foodborne illness and can cause gastroenteritis that has been associated with consumption of raw or undercooked seafood. V. vulnificus can cause primary septicemia after its ingestion, and secondary septicemia through skin lesions in individuals with preexisting conditions such as elevated serum iron levels. Bacteriophages, viruses that invade and lyse bacteria, specific to V. vulnificus and V. parahaemolyticus are naturally found in seawater and oysters. Every summer, the oyster industry is threatened by recall of oysters due to V. vulnificus and V. parahaemolyticus contamination. Destroying these human pathogens in shell stock oysters will reduce the economic loss due to recalls and protect the oyster industry's reputation, along with the health and welfare of the consumers. The purpose of this study was to evaluate and use different antimicrobial treatments to control Vibrio spp. in raw oysters. The use of bacteriophages active against V. vulnificus and V. parahaemolyticus was investigated. Bacteriophages against V. vulnificus, both opaque and translucent, and V. parahaemolyticus have seasonal distribution, occurring mainly in the summer months when both V. vulnificus and V. parahaemolyticus are at elevated number in oysters. Transmission electron microscopy showed that the predominant morphology of bacteriophages against V. vulnificus (opaque and translucent) and V. parahaemolyticus were icosahedra with thin flexible tail. Bacteriophages against V. vulnificus and V. parahaemolyticus lost their activity at an acidic pH. These bacteriophages were sensitive to elevated temperatures and V. parahaemolyticus bacteriophage was more salt tolerant than V. vulnificus opaque and translucent phages. The antimicrobial property of commercial smoked liquid against V. vulnificus and V. parahaemolyticus was also investigated. Hickory liquid smoke was effective in reducing V. vulnificus and V. parahaemolyticus population in laboratory media and in non-vacuum and vacuum packed oysters stored at 4°C.

The objective of our study was to purify lysozyme from the fluid filling cavity (shell liquor) of the eastern oysters (Crassostrea virginica) and determine the antimicrobial activity of purified lysozyme against foodborne pathogens in smoked salmon samples. Oyster shell liquor was collected over four seasons namely summer 2003, fall 2003, winter 2004, and spring 2004. Spring season showed the highest lysozyme concentration. Lysozyme was purified from 300 liters of oyster shell liquor by a two-step ion exchange chromatography using SP- and CM- Sepharose Fast Flow columns, respectively. Two hundred five mg of pure lysozyme was obtained which represented a recovery of 11.1%. The purity and molecular size of the isolated lysozyme showed a single band of about 18 KDa by SDS-PAGE. MIC assays of the oyster lysozyme were carried out by serially diluting oyster and hen egg white lysozyme to get a concentration range of 160-2.5μg/ml. Twenty four hours bacterial suspension, Brain heart Infusion or APT broth (as required) was added to each well of a 96-well plate followed by incubating the microtiter plates and measuring absorbance at 640 nm with a microplate reader. MIC results showed that oyster lysozyme had antimicrobial activity against both gram-positive and gram-negative bacteria causing food spoilage and poisoning. Smoked salmon samples were cut into 1 g pieces, inoculated with 24 h broth cultures of L. monocytogenes and S. anatum, dipped into zein propylene glycol, 0.75% agar gel, and calcium alginate coating. Calcium alginate coating was chosen as the best coating out of the three coatings. Various treatments of calcium alginate edible coatings were incorporated with oyster lysozyme or hen egg white lysozyme on the surface of the smoked salmon, allowed to air dry for 20 min and refrigerated at 4°C. Bacterial counts were determined at 0, 7, 14, 21, 28, and 35 days at 37°C for 24 h and CFU/g were determined. Combination of 160 μg/ml of oyster lysozyme and 1000 IU/g of nisin treatment was found to be the most effective treatment and was shown to retain its antimicrobial activity inside the calcium alginate coating for 35 day period.

Sugarcane bagasse is a source of lignocellulosic biomass. It is a potential renewable energy source for ethanol production. It is naturally cheap, plentiful and has high cellulose content. The sugarcane bagasse contains 34.5% cellulose, 24% hemicellulose, and 22-25% lignin. Reactive Oxygen Species (ROS), singlet oxygen (1O2), superoxide (O2-), hydroxyl radicals (OH?, and hypochlorite ion (OCl-), were found to remove both hemicellulose and lignin from sugarcane bagasse. Ox-B (Day. 2004, US Patent 6,866,870), a solution of sodium hypochlorite and hydrogen peroxide, was studied for its effectiveness as a pretreatment for lignocellulosic biomass. The cellulose structure of the bagasse was easily separated from the hemicellulose and lignin by filtration after Ox-B treatment. The remaining solids on a wet basis, were 76.2% digestible by cellulases, after a 20:1 treatment (v/w) with an Ox-B solution (10,000 ppm sodium hypochlorite : 500 ppm hydrogen peroxide). At a constant pH 8, 38.6% weight loss and 97.4% cellulose digestibility were observed. Temperature did not affect weight loss or cellulose digestibility. Above a 2% Ox-B treatment, cellulose digestibility was 100%. Cellulose digestibility increased with time for up to 3 h on treatment with Ox-B. Sequential treatments improved cellulose digestibility at lower concentrations of Ox-B. Treatment with Ox-B followed by a caustic wash produced solids that were between 80 and 100% digestible by cellulases. Our studies indicate that Ox-B is a powerful room temperature chemical oxidant that increases cellulose digestibility of sugarcane bagasse. Oxidation of bagasse, by sequential Ox-B treatments for 30 min, at a pH of 8 and room temperature, followed by a caustic wash may have industrial potential.

Traditionally, the manufacture of vinegar provided a means of utilizing a large proportion of the cull fruit from apple-packing establishments and the waste from apple processing facilities. Most vinegar is now produced from distilled grain alcohol. Vinegar may be defined as a condiment made from various sugary and starchy materials by alcoholic and subsequent acetic fermentation. The vinegar bacteria, also called acetic acid bacteria, are members of the genus Acetobacter and characterized by their ability to convert ethyl alcohol (C2H5OH) into acetic acid (CH3CO2H) by oxidation. Vinegar can be produced from various raw materials like distilled alcohol, wine, rice wine and any kind alcoholic solution by several major production techniques for making vinegar such as the Orleans process, generator process and submerged acetification process. The Orleans process consists of wood barrels filled with alcohol liquid fermented for about 1 to 3 months at 70ºF to 85ºF (21°C to 29°C). After fermentation, 1/4 to 1/3 of the vinegar is then drawn off for bottling and an equivalent amount of alcoholic liquid added. The generator process was introduced by Schutzenbach in 1823. Non compacting material is filled in the large upright wood tanks above a perforated wood grating floor. Re-circulated fermenting liquid trickles over packing material toward the bottom while air moves from the bottom inlets toward the top. The recirculation process takes about 3 to 7 days after which 2/3 of the final vinegar product is withdrawn from the tank and new alcohol solution is added. In 1955, Hromatka reported on a new method of making vinegar using submerged acetification. In this process, supply air is forced into the alcohol liquid in the tank and the material is fermented at 86°F (30°C). At the end of every cycle, 1/3 of the liquid is discharged as final product, replaced with mash containing fresh alcohol solution and a new fermentation cycle begins. The aim in the present study is to identify quality and microbial differences between the generator process and submerged acetification and to characterize the species of vinegar bacteria used in acetification.