Nivin Nasser

The challenges to food safety in Lebanon are numerous and have coalesced to pose a serious public health concern. This is evident in well-documented food poisoning outbreaks and adulteration cases. In response, the Lebanese government initiated an unprecedented food safety campaign (2015–2017) that aimed to test food samples that were randomly collected from foodservices and industries across the country. The data were made available publicly, but they were never analyzed to prioritize and determine high risk foods and most prevalent contaminants nationally or across governorates. To answer these questions, we performed an in-depth statistical analysis of the data, which included 11,625 individual food samples. Our analysis showed that water (55% of tested water samples), spices (49.3%), red meat (34.4%), poultry (30.9%) and dairy (28.3%) were the main foods associated with the highest rejection rates. The most common biological contaminants detected in rejected foods were sulfate-reducing bacteria (34.7%), Escherichia coli (32.1%), coliforms (19.6%), Staphylococcus aureus (12.8%), and Salmonella (11.6%). We conclude that Lebanon needs rigorous and sustainable programs to monitor the quality and safety of foods. Given the lack of resources, we recommend putting emphasis on extensive outreach programs that aim at enhancing food safety knowledge from farm to fork.

Meat is an important source of high biological value proteins as well as many vitamins and minerals. In Lebanon, beef meats, including raw minced beef, are among the most consumed of the meat products. However, minced beef meat can also be an important source of foodborne illnesses. This is of a major concern, because food safety in Lebanon suffers from well-documented challenges. Consequently, the prevalence and loads of fecal coliforms and Escherichia coli were quantified to assess the microbiological acceptability of minced beef meat in Lebanon. Additionally, antibiotic resistance phenotypes of the E. coli were determined in response to concerns about the emergence of resistance in food matrices in Lebanon. A total of 50 meat samples and 120 E. coli isolates were analyzed. Results showed that 98% and 76% of meat samples harbored fecal coliforms and E. coli above the microbial acceptance level, respectively. All E. coli were resistant to at least one antibiotic, while 35% of the isolates were multidrug-resistant (MDR). The results suggest that Lebanon needs to (1) update food safety systems to track and reduce the levels of potential contamination in important foods and (2) implement programs to control the proliferation of antimicrobial resistance in food systems.

Cannabis sativa is a plant that produces an oil with psychoactive and stress reduction effects and thus illegal in many nations. Lately, the beneficial properties of the plant extract are becoming better understood and perceptions are changing. As the aquaculture industry matures from a primitive extensive pond system to an industrialized intensive system, fish stress and disease incidence are increasing, with negative economic results. A nutritional ingredient that could reduce stress and disease incidence in aquacultured fish would thus be opportune. In the present work we investigated whether ether extracted cannabis oil would relieve stress, improve growth and feed conversion, and/or improve haematological indicators of disease resistance. Three diets were made to contain either soy oil, industrial hemp oil or cannabis oil and offered to tilapia for 8 weeks. At termination, survival, growth, feed conversion and blood parameters were assessed. Fish were returned to their tanks, offered the same feeds as during the experiment and respiration assessed. Cannabis extract was found to increase metabolism and thus increase feed conversion. On the other hand, cannabis had no effect on blood cell counts, total plasma protein, haematocrit or lysozyme activity. Results thus suggest that cannabis does not improve immune response of tilapia or body composition but does reduce growth rate by increasing metabolic rate.

As aquaculture evolves from extensive pond culture to intensive tank and cage systems, chemical dips and baths are increasingly being used to treat a concomitant increase in ectoparasitic and bacterial infestations. Some of the main disease‐causing agents are ectoparasites on the skin and gills of fish. Consequently, application of chemotherapeutics is increasing in aquaculture industries in order to control outbreaks of parasitic infestations. However, the toxic effect of commonly used chemotherapeutic agents on specific aquacultured fish species is often unknown. The present work was performed to test the effect of four commonly used chemical treatments on rabbitfish, Siganus rivulatus. The lethal concentrations for 50% of population (LC₅₀) of formalin, copper sulfate, potassium permanganate, and hydrogen peroxide for S. rivulatus juveniles treated for 1 h were assessed. Formalin and potassium permanganate tolerance values were determined by calculating 72‐h LC₅₀ values through probit analysis. The 72‐h LC₅₀ values for the formalin toxicity tests were 551.0 and 1.68 mg/L, respectively. LC₅₀ of copper sulfate and hydrogen peroxide could not be determined from the concentrations tested but were found to be >3 and >700 mg/L, respectively. Accordingly, treatment concentrations of formalin and potassium permanganate used for other fish species could be lethal to S. rivulatus, but the species appears to be quite tolerant to copper sulfate and hydrogen peroxide.

The present work was performed to assess whether soybean meal (SBM) could replace fish meal (FM) as a source of dietary protein in diets of the marine herbivore Siganus rivulatus. Five iso-nitrogenous (40% protein) and iso-energetic (14 MJ/Kg) diets were prepared with SBM replacing fish meal at 0%, 25%, 50%, 75%, and 100% dietary protein. A 60-day feeding trial was conducted with 240 juvenile S. rivulatus (initial body mass 1.74 ± 0.03 g). Survival, growth, feed, and protein efficiency and hematological parameters were assessed. Growth correlated negatively with increase in dietary SBM. All production parameters measured were negatively affected at all levels of SBM inclusion. There were no effects on total or differential blood counts, hemoglobin, or plasma protein, but hematocrit values were negatively correlated with SBM addition. Results suggest that total replacement of FM by SBM without adding other supplements is not recommended, even for an herbivorous marine fish such as S. rivulatus.

Marbled spinefoot, Siganus rivulatus, is a herbivorous euryhaline teleost widely distributed in the Eastern Mediterranean. It is an economically valuable species and a suitable candidate for warm water aquaculture. Accordingly, understanding the effects of environmental factors on fish metabolism is important to optimize culture conditions. Two experiments were performed to establish standard metabolic rate and study the effect of salinity on metabolism of marbled spinefoot. In the first experiment, a series of flow-through respirometry experiments was performed at 27°C and 35 g L⁻¹. The standard metabolic rate of marbled spinefoot juveniles was calculated as 0.57 ± 0.02 mg O₂ g⁻¹ h⁻¹ (mean ± SE). In the second experiment, fish were maintained at salinities of 25, 30, 35 and 40 g L⁻¹ for 2 weeks. Flow-through respirometry was performed to measure respiration rates at the various salinities. Respiration rates were similar among fish in salinities of 30, 35 and 40 g L⁻¹ but increased significantly at 25 g L⁻¹. Results suggest that despite the euryhalinity of marbled spinefoot, farmers should maintain salinity within the optimal range of 30–40 g L⁻¹ in order to improve productivity.

Disease management in aquaculture is complicated by the fact that various fish species generally vary in their susceptibility to pathogenic microorganisms, thus requiring that every species be studied independently. The present work was performed to investigate the susceptibility of marbled rabbitfish Siganus rivulatus to the potential bacterial pathogens: Aeromonas hydrophila, Mycobacterium marinum, Vibrio anguillarum, Streptococcus iniae, and Yersinia ruckeri. Fish were challenged with the various bacteria and survival and hematological responses were evaluated. Mortalities in all treatments were not significantly greater than the control. However, analyses of hematological parameters suggest that M. marinum is potentially pathogenic to S. rivulatus. Additionally, we investigated whether lesions found on wild fish collected from Beirut beach contained any of the five bacterial species of interest. None of these bacteria were present in the lesions, thus suggesting that lesions were caused by other microbes.