A milk-line sampling system to detect foodborne pathogens: A field case investigation from the United States and Argentina.

The objective of this short communication was to discuss two field case investigations to determine the usefulness of a milk-line sampling device to detect bacteria either coming from a group of cows suffering from mastitis or from the milking line potentially contaminated with environmental bacteria. In Case 1, the in-line sampling device was able to detect certain segments of the milk-line contaminated with environmental bacteria, but not coming from the cows. In Case 2, 19 out of 25 pooled in-line samples were in agreement with at least one of the individual sampled cows shedding either Staphylococcus or Streptococcus spp. or both, which accounted for 76% accordance between both methods. The in-line system, although not perfect, provided a reliable method to detect individual cows shedding mastitis-causing organisms. In conclusion, the milk-line sampling device system was able to help identify foodborne pathogens. Regular monitoring of the microbial quality of milk through a milk-line sampling device is recommended for groups of cows within the dairy herd to detect potential mastitis-causing microorganisms. Furthermore, the sampling device was an effective tool to screen the efficacy of cleaning and disinfecting mechanisms of the milk lines to identify and control potential foodborne pathogens that are collected in the bulk tank.

Assessment of pesticides in water using time-weighted average calibration of passive sampling device manufactured with carbon nanomaterial coating on stainless steel wire.

The continued contamination of water sources by pesticides is a problem that involves the life of aquatic organisms and human health, especially in countries whose economy is based on agriculture. The need to know the quality of drinking water under these circumstances is a priority for the public health of any community. Passive sampling methods allow the determination of long-term environmental pollutants through a single sample collection, reducing time and cost of analyses. One advantage of passive sampling is that it is possible to calculate a time-weighted average (TWA) concentration value or an equilibrium concentration value, depending on the type of device used and the exposure time. Passive sampling techniques using carbon nanomaterials (CNMs) have a high potential for pesticide sampling in aquatic systems. A device for passive sampling manufactured with CNMs in a microextraction system and recyclable materials was calibrated in laboratory exposure conditions over 15 days. The calibration results showed linear accumulation periods between 5 and 10 days. Sampling rates were between 0.014 and 0.146 mL day-1. The sampler was field-tested in the San Francisco river basin in the state of Minas Gerais in Brazil for 7 days. This research allowed for the detection and calculation of TWA concentrations for organochlorine pesticides such as α-HCH, 4,4-DDE, and 4,4-DD in water sources. The manufactured device demonstrated greater sensitivity than the grab sampling processes for the detection of pesticides. The performed passive sampling system using gas chromatography/mass spectrometry (GC/MS) technique allowed for the collection, detection, identification, and quantification of 26 pesticides.

A new carbon nanomaterial solid-phase microextraction to pre-concentrate and extract pesticides in environmental water.

This research describes a solid-phase microextraction device using carbon nanomaterials supported on steel threads. The device was used to pre-concentrate and extract 24 pesticides in water. The carbon nanomaterials were obtained by a chemical vapor deposition (CVD) process, using methane and acetonitrile as carbon source. The different pesticides were separated, detected, and quantified using gas chromatography coupled to mass spectrometry (GC-MS). The system, optimized and validated in the laboratory, presented good results. Linearity was between 0.0007 and 50.00 µg L-1, with determination coefficients greater than 0.9. The detection and quantification limits were in the range of 0.0002-1.1309 µg L-1 and 0.0007-3.7320 µg L-1, respectively. The studied pesticides presented recovery values in the range of 70 ± 8 to 123 ± 18%. Carbon nanomaterials exhibited high thermal and mechanical resistance, as the same fiber could be used for approximately 300 extractions. The device was applied to analyze environmental water samples collected from the São Francisco river basin in Brazil and in the Chinampas in Mexico City.

New passive sampling device for effective monitoring of pesticides in water.

The extensive use of pesticides promotes environmental contamination, mainly in surface and ground waters. However, they remain at very low concentration and present wide degradation level requiring the use of efficient devices for pesticides passive sampling. In this study, a new in situ passive sampling device was developed for monitoring and estimating time-weighted average (TWA) of pesticides in waters. The device was made with simple, recyclable and cheap materials. The sampling system involves the liquid phase microextraction technique with hollow fiber in two-phases mode. Pesticides determination was done by gas chromatography coupled to mass spectrometry. The method was optimized and validated for the determination of 29 pesticides in water, showing good linearity in the range between 0.012 and 40.00 µg L-1 with determination coefficients of R2 > 0,9649. Limit of detection (LOD) ranged from 0.009 to 0.557 µg L-1 and limit of quantification (LOQ) from 0.012 to 0.802 µg L-1. The recoveries of spiked pesticides in water samples were in the range from 96 to 130%. The method was applied to forty environmental water samples collected at São Francisco river basin, Brazil. The highest detection frequency was found for the pesticides 4,4-DDE, 4,4-DDD and propazine. They were detected in more than 20 percent of the samples.