Effects of moisture content of food waste on residue separation, larval growth and larval survival in black soldier fly bioconversion.

In order to foster sustainable management of food waste, innovations in food waste valorization technologies are crucial. Black soldier fly (BSF) bioconversion is an emerging technology that can turn food waste into high-protein fish feed through the use of BSF larvae. The conventional method of BSF bioconversion is to feed BSF larvae with food waste directly without any moisture adjustment. However, it was reported that difficulty has been experienced in the separation of the residue (larval excreta and undigested material) from the insect biomass due to excessive moisture. In addition to the residue separation problem, the moisture content of the food waste may also affect the growth and survival aspects of BSF larvae. This study aims to determine the most suitable moisture content of food waste that can improve residue separation as well as evaluate the effects of the moisture content of food waste on larval growth and survival. In this study, pre-consumer and post-consumer food waste with different moisture content (70%, 75% and 80%) was fed to BSF larvae in a temperature-controlled rotary drum reactor. The results show that the residue can be effectively separated from the insect biomass by sieving using a 2.36mm sieve, for both types of food waste at 70% and 75% moisture content. However, sieving of the residue was not feasible for food waste at 80% moisture content. On the other hand, reduced moisture content of food waste was found to slow down larval growth. Hence, there is a trade-off between the sieving efficiency of the residue and the larval growth rate. Furthermore, the larval survival rate was not affected by the moisture content of food waste. A high larval survival rate of at least 95% was achieved using a temperature-controlled rotary drum reactor for all treatment groups. The study provides valuable insights for the waste management industry on understanding the effects of moisture content when employing BSF bioconversion for food waste recycling.

Investigation of the available technologies and their feasibility for the conversion of food waste into fish feed in Hong Kong.

Food waste is the largest constituent of municipal solid waste in Hong Kong, but food waste recycling is still in its infancy. With the imminent saturation of all landfill sites by 2020, multiple technologies are needed to boost up the food waste recycling rate in Hong Kong. Conversion of food waste into animal feeds is prevalent in Japan, South Korea, and Taiwan, treating over 40 % of their recycled food waste. This direction is worth exploring in Hong Kong once concerns over food safety are resolved. Fortunately, while feeding food waste to pigs and chickens poses threats to public health, feeding it to fish is considered low risk. In order to examine the feasibility of converting food waste into fish feed in Hong Kong, this paper investigates the market demand, technical viability, feed quality, regulatory hurdles, and potential contribution. The results show that a significant amount of food waste can be recycled by converting it into fish feed due to the enormous demand from feed factories in mainland China. Two conversion technologies, heat drying and black soldier fly bioconversion, are studied extensively. Black soldier fly bioconversion is preferable because the end-product, insect powder, is anticipated to gain import approval from mainland China. The authors suggest further research efforts to speed up its application for food waste recycling in urban cities.

The first international proficiency test on ketamine and norketamine in hair.

This paper discusses the organization of the first international proficiency test (PT) programme on ketamine (K) and norketamine (NK) in hair samples. The primary objective of the programme was to evaluate the analytical capability of participating laboratories on hair analysis for K and NK via comparison of results. Authentic samples, instead of spiked samples were used in the programme to mimic the analysis of incorporated illicit drugs in real-life situations. Eight of the ten participating medical or forensic laboratories from Australia, France, Hong Kong, Italy, Singapore and the USA returned results to the organizer. Quantification methods from these laboratories were confined to GC-MS and LC-MS/MS. Performance assessment based on z-score indicated that only three laboratories achieved satisfactory results for both the analysis of K and NK. It was concluded that the overall performance of the participating laboratories was fair and there is still room for further improvement. Additional similarly designed PT programmes are recommended to be organized in order to encourage reliable measurements of illicit drugs in hair samples. Taking into account the substantial effect on the consensus values within limited number of data points, a recommendation on the provision of reference values assigned by accurate methods will be of benefit to small size PT programmes in the forensic field.

An epidemiological study on alcohol/drugs related fatal traffic crash cases of deceased drivers in Hong Kong between 1996 and 2000.

This study is designed to evaluate the correlation between fatal vehicle crashes (FVC) and consumption of alcohol and/or drugs among drivers. Between 1996 and 2000 in Hong Kong, a total of 197 FVC cases of deceased drivers were investigated. The blood and/or urine samples of the victims were examined for the presence of alcohol and drugs. The 197 cases were then classified into two groups: single-vehicle crashes (SVC) and multiple-vehicle crashes (MVC). Out of the 106 cases for the latter group, alcohol and/or drugs were detected in 22 cases (21%) while the remaining 84 cases (79%) were regarded as no significant finding. As for the 91 cases in SVC group, 51 cases (56%) were positive for alcohol and/or drugs. The findings indicate that a driver consuming alcohol and/or drugs has a higher risk of being involved in a FVC. The most frequently detected drugs for SVC group (11 cases) were: 46% central nervous system (CNS) stimulants (including designer drugs like MDMA); 36% cannabis; 18% benzodiazepines and 9% ketamine. The detected drug for the only case in the MVC group was a CNS stimulant. The number of cases with ketamine, methamphetamine and MDMA detected has increased in recent years as these party drugs have gained popularity in Hong Kong.

Rapid determination of ketamine in urine by liquid chromatography-tandem mass spectrometry for a high throughput laboratory.

In recent years, the abuse of ketamine had gained popularity in rave parties in Hong Kong. The Urinalysis Unit of the Government Laboratory of Hong Kong faced a tremendous increase in workload for ketamine analysis. The number of tests performed rose from 10 in 1999 to 15,000 in 2002. As a fully validated immunoassay test for ketamine was not available in the market, most laboratories analyzed ketamine by chromatographic techniques after liquid-liquid extraction. However, these methods reported in the literature are not suitable for high throughput laboratories. Hence, a rapid screening/confirmation method for ketamine by liquid chromatography-tandem mass spectrometry (LC-MS-MS) with a detection limit of 5 ng/ml was developed. After automated solid-phase extraction (SPE), the urine extract was analyzed for ketamine by a 2.5-min chromatographic run, the estimated recovery was 89% and the precision was 11% R.S.D. at 20 ng/ml. With the aid of an in-house developed computer program, the results were presented in spreadsheet format for easy checking. The method has been applied to our laboratory for routine ketamine analysis and a maximum of 200 samples per day can be achieved.