Food & Supplements : Safety & quality

Food & Supplements Portfolios


Easy Test for β-lactoglobulin (BLG) Milk Allergen

UW–Madison researchers have developed a simple, rapid test for detecting and quantifying BLG in food. Their method takes advantage of the fact that current signals passed through a hydrogen peroxide solution will be diminished if BLG is present.

Specifically, a known concentration of hydrogen peroxide is added to a sample suspected of containing BLG. The sample is electrolyzed using a working electrode at a fixed potential sufficient to electrolyze any BLG. The current signal within the sample is measured and compared to control curves. If BLG is present, the signal will be smaller than expected. The more the signal is diminished, the greater the concentration of BLG in the sample.

Inhibiting Storage Browning in Cheese

A UW–Madison researcher has developed a method to inhibit methylglyoxal-mediated cheese browning using a reducing agent. The reducing agent, such as glutathione or sodium sulphite, is added in an effective amount to cheese upon shredding.

Consumer-Friendly Test for Detecting Very Small Amounts of Bacteria or Other Cells

UW–Madison researchers have developed a novel method for detecting very low levels of bacteria or other cells. In this method, which is suitable for over-the-counter use by consumers, the aggregation of nanoparticles indicates the absence of the target, rather than the presence of the target as in commercially available tests.

The method uses a bifunctional linker. One portion of the linker binds to a target, while a second portion facilitates aggregation of nanoparticles. When the linker is bound to the target, little nanoparticle aggregation occurs. When the target is absent, the linker is available to facilitate aggregation of the nanoparticles. This aggregation can be observed through visual or other means, providing a simple yet sensitive method for detecting pathogenic microorganisms.

Nanoreactors as Time-Temperature Indicators for Monitoring Product Quality and Safety

UW-Madison researchers have developed a method to create a time-temperature indicator, referred to as a “nanoreactor,” that consists of a metal nanoparticle such as gold and a biopolymer carrier such as gelatin. When gelatin comes into contact with a gold-containing precursor compound such as chloroauric acid, the gelatin chemically reduces the compound to form gold nanoparticles, and then stabilizes the nanoparticles by surrounding them in a matrix of gelatin proteins.

The structures of these nanoparticles and the containing matrix change in response to time, light and temperature. This particle-level structure determines what wavelengths of light the composition absorbs, and correspondingly determines what the human eye perceives to be the color of the composition. The changes in structure, absorption and color after exposure to time and temperature change are shown in the figures below.

The results of the different conditions that induce changes to the nanoparticles are distinct and reproducible. For example, the form the nanoparticles take after being exposed to intense heat and then chilled will be different than the form after brief bursts of intense heat. As a result, these nanoreactor compositions are useful as indicators to identify when materials are no longer safe for use based on the exposure history of the material. Changes to the indicator could be monitored qualitatively through visual inspection of color change, or quantitatively by using a spectrophotometer to measure changes in light absorption. The nanoreactor also is completely safe to use as an indicator added directly to the material of interest, since both gold and gelatin are routinely put into human bodies without causing harm.

Biodegradable, Biocompatible Tannin-Chitosan Composites for Therapeutic Applications

UW–Madison researchers have developed a new composite of tannin and chitosan.  The biodegradable and biocompatible composite can be formed into hydrogel films, 3-D foams, biogels, nanoparticles or liposome coatings for a variety of therapeutic applications.

This material combines the advantages of chitosan, which has blood-clotting and antimicrobial properties, with those of tannins, which have antibacterial, antifungal, antioxidant and wound healing properties.  As compared to chitosan alone, the composite has improved stability, higher drug loading capacity, better drug release properties, improved cell uptake, greater porosity, improved tensile strength and increased thermal stability.  In addition, this composite is non-cytotoxic in vitro.

β-cyclodextrin Removes Off-Flavors from Soy Protein, Increases Flavor Stability

UW–Madison researchers have developed an efficient and cost-effective method for removing residual phospholipids from soy protein.  This method solves the off-flavor problem in soy and other proteins derived from oilseeds. 

While in solution, protein is contacted with a cyclodextrin, preferably a β-cyclodextrin.  The β-cyclodextrin forms a complex with the phospholipids in the protein.  The complex then can be separated from the remaining protein.  A sonicating step and/or enzyme pretreatment with a lipid hydrolase such as phospholipase A2 may be used to maximize phospholipid removal.

Earthworm Extract Provides a Biological Means of Decontaminating Prion-Containing Surfaces

UW–Madison researchers have developed a method of using earthworm extract to degrade prion proteins and minimize or eliminate their infectivity.  The extract can be applied to a surface that may carry prion-infected material to decontaminate it.  It contains enzymes, collectively called lumbrokinase, that are capable of reducing prion infectivity by at least 75 percent.

Non-Toxic Clostridium Botulinum Strains for Assessing Botulinal Food Safety

UW-Madison researchers have developed stable, mutant strains of C. botulinum in which the botulinal neurotoxin gene has been inactivated.  These strains could be used for challenge studies to validate different food processing conditions and testing new food formulations.

Detecting and Determining the Concentration of a Target Bioagent

UW-Madison researchers have now developed an improved sensor that requires only one membrane to determine target concentration. The membrane is fabricated from a polymeric material that dissolves when exposed to a particular biological agent. To detect the agent, the membrane is contacted with a sample of fluid. If the target bioagent is present in the fluid, the membrane dissolves at a speed dependent on the concentration of the agent. A beam of light with a specific wavelength is passed through the membrane to determine the degree of dissolution, and a detector generates an output voltage in response to the intensity of light transmitted. The change in voltage can be monitored to determine the concentration of the target agent.

Bioagent Detection Device

UW-Madison researchers have developed an inexpensive, real-time wireless microsensor for detecting biological agents in water supply networks and other aqueous environments such as the milk supply. This system includes a microdevice composed of a sampling chamber and a capacitor chamber connected by a channel. A biosensitive membrane blocks the channel between the two chambers.

To detect a biological agent, a sample of fluid is introduced into the sampling chamber and contacts the membrane. If a target bioagent is present in the fluid, it causes the membrane to become permeable or even to dissolve. When this occurs, fluid flows from the sampling chamber into the capacitor chamber, creating a very large change in impedance and an extremely large electrical output signal. The output signal is then wirelessly transmitted to a device that alerts the user to the presence of the target bioagent.

Photoluminescent Ethylene Sensors to Monitor Produce Ripening

UW-Madison researchers have developed solid solutions that can serve as the basis for a commercially useful ethylene sensor. Composed of a complex between a photoluminescent polymer and an ethylene-binding transition metal, these solid solutions glow after being exposed to a specific wavelength of light. By coupling the solid solution with diode emitters and detectors, an exemplary solid-state electronic device that responds to environmental ethylene concentrations can be created.

Thermostable Barley Alpha-Glucosidase for Improved Ethanol Production

UW-Madison researchers have developed a mutant barley alpha-glucosidase with increased thermal stability. They developed thermostable forms of the enzyme using site directed mutagenesis. Sites for mutagenesis were selected through comparisons with the sequences of other, more thermostable, alpha-glucosidase proteins.

Plasma-Aided Treatment of Surfaces Against Bacterial and Biofilm Deposition

UW-Madison researchers have developed a method for sterilizing the surfaces of such materials, and converting the contaminated deposits into inert, cross-linked films that are resistant to bacterial adhesion and attack. The process uses cold-plasma processing techniques. The material is exposed to an oxygen plasma discharge for a period of time sufficient to kill living bacterial cells and cross-link them to the material.

Method of Sensitizing Microbial Cells to Antimicrobial Compounds

UW-Madison researchers have developed a method for increasing the uptake of exogenous antimicrobial compounds by bacteria or fungi. The method involves the use of sesquiterpenoid compounds to enhance the permeability of microbial cells, allowing increased uptake of a wide variety of antimicrobial compounds.