Factors affecting imazalil and thiabendazole uptake and persistence in citrus fruits following dip treatments.

The effect of concentration, temperature, and length of treatment with imazalil (IMZ) and thiabendazole (TBZ) was studied with application to citrus fruit. The amount of residues retained by fruit after "home" washing was also monitored. IMZ uptake in citrus fruit was related to treatment duration, whereas TBZ residues was not. Residues of IMZ or TBZ fungicides were significantly correlated with dip temperature (r = 0.943 for IMZ; r = 0.911 for TBZ). Treatment at 50 degrees C produced a deposition approximately 8 and approximately 2.5 times higher than when treatments were carried out at 20 degrees C in IMZ and TBZ, respectively. No significant differences in terms of IMZ deposition were detected after treatments carried out alone or in combination. Uptake of the two fungicides was associated with their physicochemical characteristics as well as different formulation types. IMZ residues showed a great persistence during storage when applied separately, and >83% of active ingredient was present after 9 weeks of storage. IMZ residues increased with dip length, doubling when dip time increased from 0.5 to 3 min. In contrast, TBZ residues did not change with the different dip times. Following postharvest dip treatments of citrus fruit at 20 or 50 degrees C, home washing removed approximately 50% of the IMZ and approximately 90% of the TBZ.     

Orthophenylphenol and phenylhydroquinone residues in citrus fruit and processed citrus products after postharvest fungicidal treatments with sodium orthophenylphenate in California and Florida

Sodium orthophenylphenate (SOPP) has been used extensively for >40 years to control postharvest diseases of citrus fruits. Studies of the metabolism of [(14)C]SOPP have identified orthophenylphenol (OPP) as the major metabolite with phenylhydroquinone (PHQ) as a minor metabolite. The whole-fruit tolerance in the United States for OPP is 10 ppm. This study was conducted to quantify terminal OPP and PHQ residues in whole Navel oranges, grapefruit, and lemons following SOPP applications at maximum application rates and following commercial application and fruit storage practices. OPP and PHQ residues also were determined in products processed from treated Navel oranges. OPP residues in lemons, Navel oranges, and grapefruit treated with SOPP using foamer wash and shipping wax applications remained below the 10 ppm tolerance, and PHQ residues were all < or =0.439 ppm. PHQ residues in whole fruit increased with time in commercial storage. OPP residues in all Navel orange matrices except oil remained relatively stable with time in commercial storage; residues in oil declined substantially while in storage.     

Control of postharvest diseases of fruit by heat and fungicides: efficacy, residue levels, and residue persistence. A review

Extensive research has been done in recent years to reduce the heavy dependence on chemical fungicides to control postharvest diseases and disorders of horticultural crops. Alternative strategies were based on improved cultural practices, biological control, plant-defense promoters, and physical treatments such as UV illumination, radiofrequency treatment, heat therapy, and storage technologies. Among these, postharvest heat treatments such as hot water dips, short hot water rinsing and brushing, and hot air conditioning have reduced rot development and enhanced fruit resistance to chilling injury in sensitive cultivars while retaining fruit quality during cold storage and shelf life. Additive or synergistic increases in effectiveness were observed by integrating heat therapy with various chemical compounds, thus leading to significant reductions in the application of active ingredients to protect produce from decay. This paper highlights the knowledge on this topic with emphasis on heat therapy effects and factors affecting the uptake, persistence, and performance of fungicide residues when they are applied in combination with hot water.     

Residue level, persistence, and storage performance of citrus fruit treated with fludioxonil

The potential of postharvest dip treatments with fludioxonil (FLU) (a synthetic analogue of the bacterial metabolite of pyrrolnitrin), in controlling postharvest decay caused by Penicillium digitatum and Penicillium italicum of citrus fruit was investigated in comparison with the conventional fungicide imazalil (IMZ). The ultrastructural changes of fruit epicuticular wax was investigated as a function of water dip temperature, and the possible role of these changes was related to residue accumulation under FLU treatment. Residues retained by fruit were determined as a function of fungicide concentration, dip temperature, and fruit storage conditions. Scanning electron microscopy analysis revealed that fruit dipping in water at 30 or 40 degrees C did not cause differences in cuticular wax's ultrastructure in comparison to control fruit, while treatments at 50, 55, or 60 degrees C caused the disappearance of wax platelets, resulting in relatively homogeneous skin surface, due to partial "melting" of epicuticular wax. Residues of FLU in fruit treated at 20 or 50 degrees C were significantly correlated with the doses of fungicide applied. When equal amounts of fungicide were employed, the residue concentrations were notably higher (from 2.6- to 4-fold) in fruit treated at 50 degrees C than in fruit treated at 20 degrees C. The dissipation rate of FLU in "Salustiana" and "Tarocco" oranges was lower in fruit subjected to treatment at 50 degrees C. The minimal FLU concentration for almost complete decay control in artificially wounded fruit during 7-d storage at 20 degrees C was 400 mg/L active ingredient (ai) in fruit treated at 20 degrees C and 100 mg/L ai in fruit treated at 50 degrees C. Results on nonwounded Tarocco oranges subjected to 3 weeks of simulated quarantine conditions at 1 degrees C, plus 6 weeks of standard storage at 8 degrees C and an additional two weeks of simulated marketing period (SMP) at 20 degrees C revealed that almost complete decay control with FLU applications of 100 mg/L at 50 degrees C and 400 mg/L at 20 degrees C resulted in ca. 0.8 mg/kg FLU fruit residues, in agreement with results on wounded citrus fruit. When equal concentrations and temperatures were applied, FLU treatments were as effective as IMZ. In vitro trials showed a low sensitivity to FLU against P. digitatum and P. italicum isolates. MIC values for the complete inhibition of mycelium growth were >or=100 microg/mL, while ED(50) values ranged from 0.1 to 1 microg/mL for P. digitatum and from 1 to >100 microg/mL for P. italicum. The latter result suggests that care should be taken to avoid exclusive application of FLU in a sustainable program for management of fruit decay. However, integrating fungicide application and hot water dip may reduce the possibility of selecting fungicide-resistant populations of the pathogen, by increasing the effectiveness of the treatment.     

Simple and rapid determination of thiabendazole,imazalil, and o-phenylphenol in citrus fruit using flow-injection electrospray ionization tandem mass spectrometry

A simple and rapid analytical method for thiabendazole (TBZ), imazalil (IMA), and o-phenylphenol (OPP) in citrus fruit has been developed by using flow-injection electrospray ionization tandem mass spectrometry for the first time. The method involves the combined use of stable isotopically labeled internal standards (thiabendazole-(13)C(6), imazalil-d(5), and p-phenylphenol-d(9)) and a multiple reaction monitoring technique. The average recoveries for the fungicides at the tolerance levels (TBZ and OPP, 10 mg/kg; IMA, 5 mg/kg) ranged from 77 to 101%, with the coefficients of variation (CVs) ranging from 0.7 to 4.2% (n = 5). At half the tolerance levels (TBZ and OPP, 5 mg/kg; IMA, 2.5 mg/kg), the average recoveries ranged from 62 to 112%, with the CVs ranging from 0.7 to 8.4% (n = 5). The CVs of the average recoveries, obtained from lemon samples fortified with three fungicides at the tolerance levels, obtained on three different days over two weeks, ranged within 2%. The analysis time, including sample preparation and determination, is only 15 min.     

Residue levels and storage decay control in Cv. Star Ruby grapefruit after dip treatments with azoxystrobin

Cv. Star Ruby grapefruit (Citrus paradisi Macf.) were subjected to a 3-min dip in water at room temperature (20 degrees C) or at 50 degrees C with or without 25, 50, or 100 mg/L azoxystrobin (AZX). Then, the fruits were subjected to cold quarantine at 2 degrees C and 90-95% relative humidity (RH) for 3 weeks and then stored for 5 weeks at 8 degrees C and approximately 85% RH and for another 2 weeks at 20 degrees C and 80% RH to simulate a 2-week marketing period (SMP). No AZX residues were detected in the albedo and pulp following treatments at 20 or 50 degrees C, the total amount of residues being recovered from the flavedo tissue. There was a relationship between the AZX uptake in fruit and the amount of fungicide employed at 20 or 50 degrees C. When AZX was applied to the fruit at 25 mg/L at 20 degrees C, the residue level averaged 0.11 mg/kg (active ingredient, whole fruit basis). This residue concentration increased by 50 and 75% when the application rate increased from 25 to 50 or 100 mg/L, respectively. A similar pattern of accumulation was detected in fruit subjected to treatments at 50 degrees C. However, treatments at 50 degrees C produced residue levels higher than the treatments at 20 degrees C, with increases ranging from 63 to 84%, for the same concentration. Storage conditions did not affect the amount of AZX residues in the fruit. Treatment at 50 or 100 mg/L at 20 degrees C reduced the incidence of moderate to severe chilling injury (CI). Water dips at 50 degrees C reduced the incidence and severity of CI to a very low extent, with no additional advantages when hot water was used in combination with AZX. Treatments with 50 or 100 mg/L of AZX at 20 degrees C produced beneficial effects in decay control similar to those of 25 mg/L AZX at 50 degrees C or hot water alone. Better results were achieved with 50 or 100 AZX at 50 degrees C, providing complete control of decay during cold storage and with negligible decay after SMP. It was concluded that when AZX was applied at 50 degrees C, low doses of fungicide and minimal residue levels in fruit were required to control the postharvest decay of grapefruit. This treatment does not impair fruit quality and offers very interesting prospects for large scale application, due to the reduced potential toxicity of AZX to nontarget organisms and to the environment.     

Factors affecting the synergy of thiabendazole, sodium bicarbonate, and heat to control postharvest green mold of citrus fruit

The efficacy of thiabendazole (TBZ) to control postharvest decay caused by Penicillium digitatum of citrus fruit can be enhanced by co-application with sodium bicarbonate (SBC) and/or heat treatment. The impact of these treatments was investigated in citrus fruit, as a function of TBZ and SBC concentration and temperature, and were related to the amount of TBZ residues in fruit (total residues), in fruit surface, in the cuticular wax, and in the inner fruit. The residue levels of TBZ were determined in 'Valencia' oranges following a 1 min dip in an aqueous mixture of SBC at 0.5, 1, or 2 wt %/vol and TBZ at 600 or 400 mg/L (active ingredient, a.i.) at 20 or 40 degrees C and after 0 and 20 days at 17 degrees C and 90% relative humidity. The influence of SBC and heat on the TBZ residue concentration on the fruit surface, in cuticular wax, and on the inner cuticle tissue was determined in 'Salustiana' oranges after a 1 or 3 min dip in TBZ alone at 600 mg/L and 20 or 50 degrees C or for 1 min in TBZ at 600 mg/L and SBC at 2% and 20 degrees C. The efficacy of heat treatments with water, SBC, and TBZ, applied separately or in combination, was investigated on artificially inoculated 'Nova' mandarins and 'Valencia' oranges for the control of postharvest green mold caused by a TBZ-sensitive (TBZ-s) or TBZ-resistant (TBZ-r) isolate of P. digitatum. The residue levels of TBZ in fruit, evaluated as total residues, were not affected by the co-application of SBC in most samples. While TBZ residues in the fruit surface were not significantly affected by the dip temperature or by co-application of SBC, the rates of diffusion and penetration of TBZ into cuticular wax markedly increased in the presence of SBC or when TBZ was applied in combination with heat. TBZ residues in the inner tissue of fruits treated at 20 degrees C were not dependent upon the dip time or by the presence of SBC and were similar to those found in fruit treated with TBZ at 50 degrees C for 1 min, whereas significantly higher values were recorded in samples treated with TBZ at 50 degrees C for 3 min. When TBZ at 600 mg/L and 20 degrees C was applied in the presence of SBC at concentrations of 1-2 or 0.5-2%, it effectively reduced decay caused by the TBZ-resistant isolate of green mold in 'Nova' mandarins and 'Valencia' oranges. This treatment was also significantly more effective than TBZ alone to control green mold caused by a TBZ-s isolate in 'Valencia' oranges. The combination with SBC and mild heat (40 degrees C) and TBZ at 400 mg/L generally improved the control of a TBZ-r isolate of green mold with respect to the combined treatment at 20 degrees C. TBZ efficacy was also improved when applied at reduced rates (200 mg/L) and 50 degrees C, significantly suppressing green mold caused by a TBZ-s isolate of P. digitatum and effectively controlling a TBZ-r isolate. The rate of weight loss of 'Valencia' oranges was significantly increased by SBC treatment and was positively dependent upon the concentration of SBC used in the treatment, while the temperature of the treatment solution had little influence on later weight loss.     

Residue levels and storage responses of nectarines, apricots, and peaches after dip treatments with fludioxonil fungicide mixtures

Mature apricots (Prunus armeniaca), nectarines [Prunus persica var. nectarine (Ait.)], and peaches [P. persica (L.) Batsch.] were subjected to a 2 min dip treatment with warm water at 48 degrees C or with fludioxonil (FLU) at 100 mg L-1 and 20 degrees C or at 25 mg L-1 FLU and 48 degrees C and then stored at 5 degrees C and 90-95% relative humidity (RH) for 1 week plus 1 additional week at 18 degrees C and approximately 80% RH. Fruit residue uptake was determined as a function of fungicide concentration, dip temperature, treatment time (only on nectarines), and fruit storage conditions. FLU residue level was closely related to fungicide concentration and treatment temperatures and was dependent on fruit species. FLU residues showed great persistence over both storage and shelf life. Fruit dipping in water at 48 degrees C effectively reduced decay development in cvs. 'May Grand' nectarines and 'Pelese' apricots but was ineffective in cvs. 'Red Top' and 'Sun Crest' nectarines during 7 days of storage compared with nontreated fruit. Decay rates in cvs. 'Glo Haven' peaches and 'Fracasso' apricots were very low in fruit dipped in water at both 20 and 48 degrees C. Fungicide treatments at 20 and 48 degrees C resulted in the total or almost total suppression of decay in all cultivars. During shelf life, fruit became very prone to decay, averaging 25.7-100% depending on the cultivar. Fruit dipping in hot water effectively reduced decay in 'Pelese' and 'Fracasso' apricots, 'Sun Crest' peaches, and 'May Grand' nectarines as compared to control, but was ineffective in 'Glo Haven' and 'Red Top' peaches. Fungicide treatments at 20 degrees C were more effective than hot water in most cultivars. The combination of FLU with water at 48 degrees C further improved the fungicide performance. Indeed, reduced levels (a fourth) of active ingredient were required to achieve a control of decay comparable to that for treatment at 20 degrees C. Residue levels in fruit after treatment with 100 mg L-1 FLU at 20 degrees C or with 25 mg L-1 FLU at 48 degrees C averaged approximately 0.6-2 mg kg-1, which were notably lower than the maximum residue limit (5 mg kg-1) allowed in the United States for stone fruit.     

Study of carbendazin residue accumulation on greenhouse and field-grown strawberries, after successive treatments with benomyl

Benomyl, a systemic fungicide used in preharvest treatments to prevent Botrytis and other fungal diseases, metabolizes to carbendazim (MBC). A study was undertaken to determine if the total residues of MBC of greenhouse and field-grown Douglas strawberries accumulate in fruits after successive fortnightly treatments with a commercial preparation of benomyl. Statistical analysis of the data obtained indicates that residues of MBC do not accumulate in fruits; on the contrary, they decrease over time.     

Comparison of ozone and UV-C treatments on the postharvest stilbenoid monomer, dimer, and trimer induction in var. 'Superior' white table grapes

Postharvest treatment of seedless white table grapes (var. 'Superior') with different gas ozone concentrations (3.88 and 1.67 g/h) for 1, 3, and 5 h induced an increase in stilbenoid biosynthesis [trans-resveratrol, piceatannol, and viniferinas (resveratrol dehydrodimers and dehydrotrimers)] during storage at 22 degrees C and 95% relative humidity. The maximal resveratrol concentration was reached after 2 days of storage, and this amount was similar to that induced by optimized UV-C treatments (1 min, 510 W, 40 cm). Although similar resveratrol concentrations accumulated in grapes after both UV-C and O3 treatments (maximum ozone production and time), the ozone treatment was more efficient in inducing viniferins accumulation in grape berries. A sequence in the biosynthesis of stilbenoids was observed, starting with the resveratrol monomer, continuing with the resveratrol dehydrodimers epsilon-viniferin and delta-viniferin, and ending with four different resveratrol dehydrotrimers. These trimers were different from alpha-viniferin, a trimer previously reported to be induced in grapes after biotic and abiotic stresses. Two alpha-viniferin isomers were also detected in the ozone-treated grapes, although at very low concentrations that prevented their quantification.     

Impact of postharvest disease control methods and cold storage on volatiles, color development and fruit quality in ripe 'kensington pride' mangoes

Postharvest diseases of mango fruit (Mangifera indica L.) cause economic losses during storage and can be controlled by chemical, physical, or biological methods. This study investigated the effects of different physical and/or chemical disease control methods on production of volatiles, color development and other quality parameters in ripe 'Kensington Pride' mango fruit. Hard mature green mango fruit were harvested from an orchard located at Carnavon, Western Australia. The fruit were heat-conditioned (8 h at 40 +/- 0.5 degrees C and 83.5 +/- 0.5% RH), dipped in hot water (52 degrees C/10 min), dipped in prochloraz (Sportak 0.55 mL x L(-1)/5 min), dipped in hot prochloraz (Sportak 0.55 mL x L(-1) at 52 degrees C/5 min), dipped in carbendazim (Spin Flo 2 mL x L(-1)/5 min), and dipped in hot carbendazim (Spin Flo 2 mL x L(-1) at 52 degrees C/5 min). Nontreated fruit served as control. Following the treatments, the fruit were air-dried and kept in cold storage (13 +/- 0.5 degrees C) for three weeks before being ripened at 21 +/- 1 degrees C. The ripe pulp of the fruit that was treated with hot prochloraz or carbendazim at ambient and high temperatures showed enhanced concentrations of volatiles, while heat conditioning and hot water dipping did not significantly affect the volatile development. Ripening time, and color development were measured daily while disease incidence and severity, weight loss, firmness, and concentrations of soluble solids, titratable acidity, ascorbic acid, total carotenoids, and volatiles were determined at the eating soft ripe stage. Hot water dipping or fungicide treatments (at ambient or at a high temperature) reduced postharvest diseases incidence and severity. Fruit quality (soluble solids concentration, titratable acidity, ascorbic acid and total caretonoids) was not substantially affected by any of the treatments.     

Dehydrin from citrus, which confers in vitro dehydration and freezing protection activity, is constitutive and highly expressed in the flavedo of fruit but responsive to cold and water stress in leaves

A cDNA encoding a dehydrin was isolated from the flavedo of the chilling-sensitive Fortune mandarin fruit (Citrus clementina Hort. Ex Tanaka x Citrus reticulata Blanco) and designed as Crcor15. The predicted CrCOR15 protein is a K2S member of a closely related dehydrin family from Citrus, since it contains two tandem repeats of the unusual Citrus K-segment and one S-segment (serine cluster) at an unusual C-terminal position. Crcor15 mRNA is consistently and highly expressed in the flavedo during fruit development and maturation. The relative abundance of Crcor15 mRNA in the flavedo was estimated to be higher than 1% of total RNA. The high mRNA level remained unchanged during fruit storage at chilling (2 degrees C) and nonchilling (12 degrees C) temperatures, and it was depressed by a conditioning treatment (3 days at 37 degrees C) that induced chilling tolerance. Therefore, the expression of Crcor15 appears not to be related to the acquisition of chilling tolerance in mandarin fruits. However, Crcor15, which was barely detected in unstressed mandarin leaves, was rapidly induced in response to both low temperature and water stress. COR15 protein was expressed in Escherichia coli, and the purified protein conferred in vitro protection against freezing and dehydration inactivation. The potential role of Citrus COR15 is discussed.     

Soil respiration, nitrogen mineralization and uptake in barley following cultivation of grazed grasslands

 Soil tillage was studied as a strategy to synchronize N mineralization with plant demand following ploughing of two types of grazed pastures [ryegrass/white clover (Lolium perenne/Trifolium repens) and pure ryegrass]. The swards were either rotovated and ploughed or ploughed only. Soil respiration, as determined by a dynamic chamber method, was related to net N mineralization and to plant N uptake in a subsequent spring barley crop (Hordeum vulgare). Diurnal variations in temperature were important for the CO₂ flux and care must be taken that temperatures during measuring periods are representative of the daily mean. Soil tillage increased the CO₂ flux considerably compared with untilled soil with total emissions of 2.6 and 1.4 t C ha^–1, respectively, from start of April to end of June. Sward type or rotovation did not markedly influence accumulated emissions. Rotovation significantly increased the content of nitrate in the soil until 43 days after rotovation, showing that net N mineralization occurred rapidly during this period, in spite of low soil temperatures (5–10  °C). Rotovation increased barley grain yield by 10–12% and N-uptake by 14%. For both sward types, rotovation caused an extra N-uptake in harvested plant material of about 12 kg ha^–1. The availability of soil inorganic N at the early stages of barley was important for the final yield and N-uptake. The results indicated that soil biological activity was not enhanced by rotovation and that the yield effect of rotovation was mainly caused by quicker availability and better synchrony between N mineralization and plant uptake due to earlier start of decomposition. Received: 3 May 2000     

Effect of tillage and residue management on hydrol-thermal regimen, nutrient uptake and yield of wheat in a river deposit

Field experiments were conducted on a river deposit during 1983–1984 and 1984–1985 in order to study the effect of different soil management practices, such as zero tillage with surface-applied crop residue mulch at a rate of 10 t ha⁻¹ (ZT+M), conventional tillage (CT), CT+ surface-applied crop residue mulch at a rate of 10 t ha⁻¹ (CT + M), CT+crop residue incorporation at a rate of 10 t ha⁻¹ (CT + SI), CT + farmyard manure incorporation at a rate of 10 t ha⁻¹ (CT + FYM), on soil hydro-thermal regime root growth, nutrient uptake and dry matter yield of winter wheat (Triticum aestivum L.). The soils of the site are classified as Entisol, Typic Psammaquent with pH 6.0, cation exchange capacity 10 c mol (p⁺) per kg in the surface (0–0.3 m) depth. In the CT + M and CT + FYM treatments, higher water retention was observed compared to CI. The minimum soil temperature was also raised by 3°C under CT + M to CT at 0.1-m depth. CT + M and CT + FYM had significantly higher root mass density compared with other treatments at all stages of crop growth. The nitrogen (N) uptake under these two treatments was also significantly higher compared to CT. Under CT+M, plants did not suffer from N stress compared to other treatments. Phosphorus (P) uptake (except at tillering) and potassium (K) uptake under CT+M and CT + FYM were significantly higher than for all the other treatments. Treatments ZT+M and CT+SI behave simply to CT in terms of hydro-thermal regime, root growth, nutrient uptake and dry matter yield. The grain yield under CT+M and CT+FYM during 1983–1984 and 1984–1985 was significantly higher than that under all the other treatments.     

Nutrient uptake,nitrogen use efficiencies,and energy indices in soybean under various tillage systems with crop residue and nitrogen levels after combine harvested wheat

Abstract

A field study was conducted during kharif (rainy season) to study nutrient uptake, nitrogen use efficiencies, and energy indices in soybean under various tillage systems with crop residue and nitrogen levels after combine harvested wheat for two consecutive years. The treatments included three planting methods (Happy Seeder sowing, Straw Chopper?+?Zero Tillage sowing and Conventional sowing) and four nitrogen levels (0, 75, 100, and 125% recommended nitrogen). Nitrogen (N), phosphorus (P), and potassium (K) uptake by seed and straw were significantly higher in Happy Seeder sowing than Straw Chopper?+?Zero Tillage sowing and conventional sowing. Agronomic efficiency, physiological efficiency, and apparent recovery were not influenced significantly by different planting methods whereas partial factor productivity, energy output, net energy, energy use efficiency, and energy productivity were significantly higher in Happy Seeder sowing than Straw Chopper?+?Zero Tillage sowing and conventional sowing. N and P uptake by seed and straw increased significantly from 0 to 75 and 75 to 100% recommended N and similar trend was found in K uptake by seed and straw. Agronomic efficiency, apparent recovery and energy output were increased up to 100% recommended N. However, partial factor productivity was decreased significantly with increase in N levels and physiological efficiency was not influenced significantly by different N levels.     

Assessment of egg nutrient compositional changes and residue in eggs,tissues, and excreta following oral administration of atorvastatin to laying hens

Laying hens were fed a control diet alone or with 0.06 g of atorvastatin, a synthetic 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, per 100 g of diet for 20 days. Compared to controls, egg yolks from treated hens contained greater amounts of amino acids and reduced levels of total fatty acids and cholesterol. In contrast, egg albumen amino acid contents were unaffected by dietary treatments. In a residue study, seven hens each received a single oral dose of approximately 20 microCi of [(14)C]atorvastatin. Approximately 71% of the radioactivity was recovered in the excreta and liver, whereas virtually no radioactivity was detected in kidney, heart, muscle, bile, plasma, or egg albumen at 15 days postdosing. Yolk radioactivity peaked at 4 days postdosing in six of the seven birds and was absent in eggs laid after day 10. Reminiscent of that of certain antibiotic drugs, the atorvastatin egg residue pattern appeared to coincide with the physiological pattern of daily yolk accretion within the ovary.     

Relationships between volatile production, fruit quality, and sensory evaluation in Granny Smith apples stored in different controlled-atmosphere treatments by means of multivariate analysis.

Aroma compounds, quality parameters, and sensory evaluation of Granny Smith apples were analyzed after 3, 5, and 7 months of cold storage in three controlled-atmosphere (CA) treatments, in which oxygen and carbon dioxide were held at 1, 2, and 3%. During poststorage ripening, the apples were kept at 20 degrees C for 1, 5, and 10 days before analytical measurements were made. The highest volatile emission was obtained after 5 months of storage in all CA treatments, reaching its highest value when a low-oxygen CA (LO) was used. Ultralow-oxygen CA (ULO) showed the highest ability to maintain apple firmness. The correlation among analytical and sensory parameters suggests that ethyl 2-methylbutyrate, 1-butanol, pentyl acetate, and tert-butyl propionate are the aroma compounds with the highest influence in the sensorial score. Concerning CA treatments, LO and ULO appear to be very valuable technologies for maintaining the sensorial quality even after 7 months of storage.     

Tissue distribution, metabolism, and residue depletion study in Atlantic salmon following oral administration of [3H]emamectin benzoate

Atlantic salmon (approximately 1.3 kg) maintained in tanks of seawater at 5 +/- 1 degrees C were dosed with [3H]emamectin B1 benzoate in feed at a nominal rate of 50 microg of emamectin benzoate/kg/day for 7 consecutive days. Tissues, blood, and bile were collected from 10 fish each at 3 and 12 h and at 1, 3, 7, 15, 30, 45, 60, and 90 days post final dose. Feces were collected daily from the tanks beginning just prior to dosing to 90 days post final dose. The total radioactive residues (TRR) of the daily feces samples during dosing were 0.25 ppm maximal, and >97% of the TRR in pooled feces covering the dosing period was emamectin B1a. Feces TRR then rapidly declined to approximately 0.05 ppm by 1 day post final dose. The ranges of mean TRR for tissues over the 90 days post dose period were as follows: kidney, 1.4-3 ppm; liver, 1.0-2.3 ppm; skin, 0.04-0.09 ppm; muscle, 0.02-0.06 ppm; and bone, <0.01 ppm. The residue components of liver, kidney, muscle, and skin samples pooled by post dose interval were emamectin B1a (81-100% TRR) and desmethylemamectin B1a (0-17% TRR) with N-formylemamectin B1a seen in trace amounts (<2%) in some muscle samples. The marker residue selected for regulatory surveillance of emamectin residues was emamectin B1a. The emamectin B1a level was quantified in individual samples of skin and muscle using HPLC-fluorometry and was below 85 ppb in all samples analyzed (3 h to 30 days post dose).     

Quantification of total furocoumarins in citrus oils by HPLC coupled with UV, fluorescence, and mass detection

Furocoumarins or psoralens represent a class of photosensitizers whose use level is likely to be restricted to 1 ppm in cosmetic products by the EU. A reversed-phase HPLC method was developed to separate the 15 main furocoumarins present in citrus oils. Quantification by UV, fluorescence, or mass detectors was compared in terms of linearity and limit of detection. Cold-pressed oils of different citrus species were analyzed using this method. This method could be implemented in quality control laboratories equipped with an HPLC system and a UV diode array detector. Because of possible coelutions, the UV-spectral data should be carefully examined to avoid misleading interpretations of peaks.