The presence of undesirable heavy metals, pesticide residues, and microbial contaminants in fresh produces is a worldwide public health concern. This study was undertaken to evaluate the residual pesticides (Diazinon, Malathion, Cypermethrin, Dimethoate, Quinalphos, and Chloropyrofos), heavy metal contamination (Pb, Cd, and Cr), and microbiological quality and safety of 4 common raw salad vegetables (RSVs) samples from different local markets in Dhaka. Results showed the presence of heavy metals residues were within the acceptable limits of local and international standards. None of the above-mentioned pesticides were found in tomato and cucumber samples but presence of Dimethoate was noticed in 13 coriander samples (12.94-158.3 μg/kg) and 7 lettuce samples (9.6-74.8 μg/kg) exceeding the maximum permissible limit of EU guideline. The microbiological analysis showed irrespective of RSV types, total aerobic bacteria was present in higher number (4.0-7.0 log CFU/g), whereas 3.36-5.57 log CFU/g coliform count was recorded. In comparison with retail markets, lower level of total aerobic, and coliform bacterial presence was observed in the samples collected from sophisticated shops, but presence of E. coli and Salmonella spp. were evident in more than 60% samples in these shops. However, 50% and 33% samples from wholesale and retail markets respectively were noticed to be contaminated with Staphylococcus spp. Irrespective of RSV types, isolated E. coli were found resistance to 2-5 different antibiotics, where Salmonella spp. isolated from cucumber and coriander leaves showed resistance against 4-8 different antimicrobials. Therefore, the study results demonstrated that, the presence of residual pesticides, multidrug resistant E. coli and Salmonella spp. in the RSV samples posing concern when consumed raw. The regulatory bodies are expected to monitor and ensure the overall quality standards are in place and practiced by food producers and marketers responsible for handling and distribution of RSVs.

In this study, we evaluated the ability of waste shell powder (WSP) and moringa seed powder (MSP) individually or in combination to eliminate dye, heavy metal and resistant bacteria from the industrial wastewater (IWW). The presence of dyes, heavy metals, approximately 7.0 log CFU/ml of aerobic bacteria and 3.0–4.0 log CFU/ml of other pathogens including Escherichia coli, Pseudomonas aeruginosa, Citrobacter freundii, Serratia liquefaciens and Bacillus cereus was evident in IWW of both tannery and textile industries. In addition, depending on the type of bacterial species each bacterium was resistant to as high as 50 ppm of multi-metal (Cr⁶⁺, Cd²⁺ and Pb²⁺ or its combination) and even multi-drug resistant (amoxicillin, ampicillin, cefixime, ceftazidime, and tazobactam). Combined use of MSP (0.8 gm/100 ml IWW) and WSP (0.2 gm/100 ml IWW) treatment was able to discolor the IWW within 4 h and took 24 h to eliminate heavy metals and pathogenic bacteria to non-detectable level from the IWW, simultaneously. On the other hand, individual use of MSP or WSP was not found effective enough to remove or eliminate dye, heavy metal and bacteria simultaneously from the IWW. Similar experimental results were observed in the challenge test with laboratory-prepared effluent water containing 35.0 ppm Remazol Brilliant Blue R dye and maximum 50 ppm Cr⁶⁺. Thus, the combination of these two bio-sorbents could be applicable in IWW treatment before being discharged into the environment.

This study investigates the effects of heat and ultrasonic treatments on the physicochemical parameters and rennet-induced coagulation properties of milk from a variety of species, including cow, goat, buffalo, and donkey. Milk samples were subjected to heat treatments at different temperatures (65 °C, 80 °C, 90 °C, 100 °C) and ultrasonic treatment at varying power levels (200 W, 400 W, 600 W, 800 W, 1000 W). The results revealed that changes in turbidity, particle size, zeta potential, secondary structure, and surface hydrophobicity were altered by both ultrasonic and heat treatments, as well as the kind of milk. Ultrasonic treatment of cow milk decreased α-helix content while increasing β-turn content. Under similar ultrasonic treatment, goat milk showed a considerable increase in β-sheet content, whereas β-turn and random coil contents decreased compared to control samples. Notably, the water-holding capacity of gels formed from all four types of milk increased significantly with the intensity of ultrasonic and heat treatments. The hardness of buffalo milk gels increased significantly after ultrasonic and thermal treatments, ranging from 63 °C for 30 min to 90 °C for 15 min, but the hardness of cow and goat milk gels increased in varying degrees compared to their control samples. Furthermore, gels from cow and goat milk had higher storage modulus (G') and loss modulus (G'') than those from buffalo and donkey milk, and changes in G' and G'' from the examined milk were altered by ultrasonic and heat treatments. These findings offer important insights into refining milk processing procedures to improve dairy product quality and usefulness.

A simple and inexpensive water purification method was developed using natural coagulant (moringa seed powder) and antibacterial agents (scallop powder) followed by bio-sand filtration. In this study, surface water from different sources (e.g. pond, canal, lake and river) were treated with combined moringa seed powder, and scallop powder (MOSP) at a ratio of 2:1 for 10 minutes showed a clear water layer at the top and a sediment layer at the bottom. The clear water was then passed through an 8-fold sari cloth and/or natural bio-sand filtration and the resulting water was found drinkable. The microbiological and physico-chemical quality of this water showed non-significant differences compared to the US EPA drinking water quality parameters. Moreover, no cytotoxic effect of MOSP with BHK-21 and HeLa cells, nor any bacterial endotoxins was observed indicating use of MOSP does not pose any adverse health effect. Furthermore, the quality of six months stored water at room temperature was found acceptable, indicating the usefulness of this technology for drinking water purpose. On the other hand, the sediment or sludge produced in this process could be used in agriculture fields after proper compost. Therefore, this simple, inexpensive and ecofriendly methods could be used in drinking water scarcity areas of the world.

Background. For over a decade, solid tannery waste has been converted into protein concentrate and used as a feed ingredient because of its cheap availability. However, as chromium sulfate is commonly used in the tanning process, the chromium (Cr) content of tanned skin-cut wastes (SCW) may enter the edible parts of poultry through feed. Therefore, there is a chance that Cr and other heavy metals may be present in the edible portion of poultry and consequently transfer to humans upon poultry consumption. Objectives. In this study, skin-cut wastes (SCW)-based poultry feed and the edible parts of chicken fed with this feed were analyzed to understand the potential health risks of their use as poultry feed. Methods. In the present study, the presence of heavy metal content in SCW, poultry feed, and edible portions of different kinds of chicken was determined using atomic absorption spectrophotometer methods and the associated health risk estimation was calculated by comparing the target hazard quotient (THQ)...