Fresh cucumber flavor in refrigerated pickles: comparison of sensory and instrumental analysis

The ability of nonacidified, refrigerated pickled cucumbers to produce the fresh cucumber flavor impact compounds (E,Z)-2,6-nonadienal and (E)-2-nonenal declined during storage. Production of these compounds decreased as the pH of refrigerated cucumbers was reduced. Despite the fact that the concentrations of (E,Z)-2,6-nonadienal and (E)-2-nonenal generated were over 10(5)-fold greater than the threshold levels, it was possible for a sensory panel to consistently detect differences in the intensity of fresh cucumber flavor, provided the pH difference between samples was 1 unit or greater. The presence of spices did not interfere with the ability of panelists to detect differences in fresh flavor intensity. There was a linear correlation between sensory scores and the amount of (E,Z)-2,6-nonadienal produced by cucumbers equilibrated at different pH levels.     

The high potency of ME-5343 to aphids is due to a unique mechanism of action

ME-5343 (afidopyropen) is a new and promising insecticide with an unknown mechanism of action that is effective against sucking insects. ME-5343 was highly toxic to pea aphids (Acyrthosiphon pisum), being more toxic than six other widely used insecticides. In contrast, ME-5343 was practically non-toxic to eight other species of insects we tested. ME-5343 was not toxic to German cockroaches (topical application) or American cockroaches (injection), suggesting that lack of toxicity in these species is not due to lack of cuticular penetration. House flies are insensitive to ME-5343 by topical, residual and feeding exposure. Addition of synergists did not change this result, suggesting that insensitivity to ME-5343 in house flies is not due to rapid detoxification nor is it dependent on the method of bioassay used. ME-5343 did not cause firefly lanterns to glow, nor did it prevent the octopamine stimulated lantern glow. Extracellular recordings of action potentials from a tonically active motor nerve of crayfish in situ showed no effects of ME-5343 at concentrations up to 10⁻⁵ M. These results suggest that the target site of ME-5343 is not the voltage gated sodium channel, voltage gated potassium channel, GABA gated chloride channel, nicotinic acetylcholine receptor, acetylcholinesterase, octopamine receptor or glutamate receptor. ME-5343 injected into crayfish caused flextion of the legs and tail, similar to the symptoms induced by 5-HT (serotonin). We evaluated the effect of ME-5343 on 5-HT2-like receptors with intracellular recordings of excitatory post-synaptic potentials from the peripheral neuromuscular junction of the crayfish and found no effect of ME-5343. Thus, ME-5343 was neither an agonist nor antagonist of 5-HT2 receptors, did not affect neurotransmitter release and did not affect glutamate receptors. We conclude that ME-5343 is highly toxic to aphids and that this is due to a unique, and currently undefined mechanism of action.     

Metabolic responses of juvenile GIFT strain of Nile tilapia (Oreochromis niloticus) to dietary L‐tryptophan supplementation

A 60‐day indoor feeding trial was conducted to evaluate the effects of dietary tryptophan supplementation on growth performances, whole‐body chemical composition, expression of muscle growth‐related genes (MyoD, myogenin and myostatin), and haematological and biochemical responses of juvenile genetically improved farmed tilapia (GIFT). Five corn–soy‐based isonitrogenous and isoenergetic diets were formulated to contain graded levels of dietary tryptophan (2.6, 3.2, 3.7, 4.2 and 4.8 g/kg of diet). Each diet was randomly assigned to triplicate groups of 30 fish (5.3 ± 0.1 g) per experimental unit, which were fed thrice a day (9:00, 13:00 and 17:00 hr). Maximum growth performances and feed utilization were observed in fish fed tryptophan at 3.7 g/kg of diet. There was no significant (p > .05) effect on whole‐body composition and amino acid profile by dietary tryptophan supplementation. However, significant (p < .05) differences were observed in plasma metabolites and the mRNA expression of MyoD, myogenin and myostatin. Serum cortisol level was found significantly lowest in fish fed tryptophan at 3.7 g/kg of diet. Second‐order polynomial regression analysis of weight gain and nitrogen gain against dietary tryptophan levels indicated that the optimum dietary tryptophan requirement for maximum growth and feed utilization of juvenile GIFT tilapia was 3.8 g/kg of diet.     

Battery-free Radio Frequency Identification (RFID) Sensors for Food Quality and Safety

Market demands for new sensors for food quality and safety stimulate the development of new sensing technologies that can provide an unobtrusive sensor form, battery-free operation, and minimal sensor cost. Intelligent labeling of food products to indicate and report their freshness and other conditions is one important possible application of such new sensors. This study applied passive (battery-free) radio frequency identification (RFID) sensors for the highly sensitive and selective detection of food freshness and bacterial growth. In these sensors, the electric field generated in the RFID sensor antenna extends from the plane of the RFID sensor and is affected by the ambient environment, providing the opportunity for sensing. This environment may be in the form of a food sample within the electric field of the sensing region or a sensing film deposited onto the sensor antenna. Examples of applications include monitoring of milk freshness, fish freshness, and bacterial growth in a solution. Unlike other food freshness monitoring approaches that require a thin film battery for operation of an RFID sensor and fabrication of custom-made sensors, the passive RFID sensing approach developed here combines the advantages of both battery-free and cost-effective sensor design and offers response selectivity that is impossible to achieve with other individual sensors.     

Hospice in a zoologic medicine setting

Forty years ago, Dr. Elizabeth Kubler-Ross in her landmark book On death and dying observed "maybe at the end of our days, when we have worked and given, enjoyed ourselves and suffered, we are going back to the stage that we started out with and the circle of life is closed." Just as human life expectancy has steadily increased over the last 4 or 5 decades, animal life expectancy has increased, including that of zoologic species. With this has come a need for humans to openly and frankly deal with end-of-life issues for themselves and for their animals, including those in zoos. By necessity, zoos have been dealing with problems such as aggressive pain management and triage, and efforts to incorporate end-of-life care into zoologic medicine. But these efforts have yet to include formal acknowledgment that they are a basic form of hospice. Hospice for humans, and now for companion animals, includes much more than pain relief and geriatric care. This article reviews the concepts and basic practices of hospice and the closely related field of palliative care, their relatively recent application to companion animal care, potential applications to zoologic medicine, and the ways this could provide opportunities for personal growth of zoo visitors and staff, including veterinary staff.