Migration of a UV stabilizer from polyethylene terephthalate (PET) into food simulants.

The migration characteristics of the UV stabilizer Tinuvin 234 (2-(2H-benzotriazol-2-yl)-4,6-bis (1-methyl-1-phenylethyl)phenol) into food simulants has been measured from polyethylene terephthalate (PET) using HPLC with UV detection. Ethanol/ water, isooctane and a fractionated coconut oil simulant (Miglyol) were used as food simulating solvents. The migration characteristics were measured at temperatures in the range of 40-70 degrees C. Diffusion coefficients were determined to be in the range of 1 x 10(-14) cm2 s(-1) to 1 x 10(-18) cm2 s(-1). At 40 degrees C, the amount of migration into 95% ethanol after 10 days was 2 microg dm(-2). Isooctane is determined to be a good fatty food simulant that provides similar results for PET to those of fatty foods.

Evaluating the potential for recycling all PET bottles into new food packaging.

To evaluate the feasibility of recycling all PET bottles into food packaging, realistic estimates of the maximum concentration of contaminants that might be expected in the polymer are needed. To estimate the maximum concentration of a contaminant that might be in PET from the storage of non-food substances, sorption experiments into two types of PET were performed. These test materials were 0.8mm thick amorphous PET (a relative sink for contaminants) and commercial PET bottle wall. Using a commercial shampoo containing 1% lindane (C6H6Cl6), the test materials were stored in contact with the shampoo at 20 and 40 degrees C for 231 days. This commercial shampoo also represents an extreme case because it contains 7% acetone, a solvent which swells PET, further enhancing sorption of chemicals. Additional sorption experiments into PET were performed by preparing solutions of 10% toluene in Miglyol (a fractionated coconut oil), 10% benzophenone in Miglyol, 5% 2-butoxyethoxy ethanol (2-BE) in 50/50 water/ethanol, and 10% methyl stearate in heptane. Sorption data from the shampoo into PET illustrate Fickian behaviour. Specifically, the amount of sorption at room temperature is approximately40 times less than that at 40 degrees C. The amount of lindane sorbed into PET from the shampoo after 231 days was 0.1 and 3.7 mgdm(-2) at 20 and 40 degrees C respectively. These values correspond to 28 and 765 mg kg(-1) on a mass/mass basis. All sorptions are within the ranges measured and published by other authors using surrogate contamination testing schemes. Additionally, actual bottles from recycle bins were analysed for the amout of contamination. Results are discussed in terms of potential consumer exposure to non-food contaminants in food containers made of recycled PET and in relation to the surrogate testing methods recommended by the Food and Drug Administration (FDA) for determining the compatibility of a PET recycling process to produce containers suitable for food-contact use.

Determination of the diglycidyl ether of bisphenol A and its derivatives in canned foods.

Migration of the diglycidyl ether of bisphenol A (DGEBA) to food from can enamels and can pull-top seals is reported. Derivatives of DGEBA are also determined in some foods. Levels of DGEBA in the foods surveyed in this study range from nondetected (<0.3 ppb) to 50 mg/kg as determined by liquid-liquid extraction or solid-phase extraction coupled with high-pressure liquid chromatography using fluorescence detection. Confirmation of the analytes is by gas and/or liquid chromatography with mass spectral analysis. Fourier transform infrared spectroscopy with 30 degrees specular reflectance/transmittance is used to characterize the coated food contact surfaces. Stability studies with DGEBA in water, acid, and saline solutions show conversion to the hydrolysis products and chloro adducts occurs readily. The presence of DGEBA derivatives in food demonstrates that analysis for DGEBA migration alone is not a good indicator of total migration from can coatings to foods.

Effect on neuromuscular transmission of repeated administration of an organophosphorus compound, metrifonate, during treatment of children with urinary schistosomiasis.

Muscle action potential amplitude recorded from abductor pollicis brevis in response to nerve stimulation was measured in 55 children during treatment of urinary schistosomiasis with metrifonate (3 doses at 2 weekly intervals). Mean erythrocyte cholinesterase activity was 52-75% of pretreatment value in different groups when examined electrophysiologically. Twenty-six children acted as controls. There was no difference in amplitude between control and exposed subjects 2 weeks after the 2nd dose. Six hours after the 3rd dose, amplitude was larger in some subjects. This effect was not related to dose or degree of cholinesterase inhibition and was thought unlikely to be the result of treatment. Three children who received the highest dose of metrifonate had developed repetitive activity 6 hr later. The criteria for its identification are described.

Initial experiences with praziquantel in the treatment of human infections due to Schistosoma haematobium.

Initial studies of the tolerance and efficacy of praziquantel in the treatment of human infections due to Schistosoma haematobium were conducted at the WHO Tropical Diseases Research Centre, Ndola, Zambia. The first stage of the trial was a double-blind assessment against placebo of the tolerance and efficacy of oral doses of 1x20, 2x20, or 3x20 mg/kg in patients with a minimum schistosome egg excretion of 50 per random 10-ml sample of urine. Later a single-blind trial was carried out of the efficacy of three oral doses, each of 20 mg/kg, given at 4-hour intervals, or of a single oral dose of 50 mg/kg.In 79 young Zambians with S. haematobium infections (and often other parasitic infections), patient tolerance to the drug was very good, only minor post-treatment symptoms of intermittent epigastric pain, anorexia, and headache being noted, all of short duration.No changes of clinical relevance were detected in the results of a battery of haematological and biochemical tests. Post-treatment eosinophilia occurred in 42% of drug-treated patients but also in 30% of those given placebo. Serial electrocardiograms revealed no changes of significance.At six months after treatment, of 73 patients followed up, only 1 case of parasitological failure was detected. At one year, 66 (83.5%) of 79 patients with S. haematobium infection were followed up and 2 (2.5%) parasitological failures were detected.Two years after treatment, 45 (57%) of 79 patients with S. haematobium showed negative urines, 7 (9%) had positive hatching tests, and 27 (34%) were absent.

Two new field techniques for detection and counting of Schistosoma haematobium eggs in urine samples, with an evaluation of both methods.

Two new techniques for the quantitative determination of Schistosoma haematobium egg densities in urine samples, the first using sedimentation and the second filtration, have been developed and evaluated. In the first method the concentrated sediment is examined in a counting chamber under a low-power microscope and in the second method the final concentration achieved by filtration is also examined microscopically. Both procedures are easily carried out under primitive field conditions, while retaining their reproducibility and reliability. The techniques can be useful in mass surveys of populations suffering from schistosomiasis.

A simple device for counting microorganisms.

This paper describes a simple but accurate device for counting helminth and schistosome eggs as well as other organisms of similar size that can be suspended in liquids. The device presents the additional advantages of being inexpensive and durable.