Hussein F. Hassan

Overall and Fluid-to-particle Heat Transfer Coefficients associated with Canned Particulate non-Newtonian Fluids during Free Bi-axial Rotary Thermal Processing

Abstract Heat transfer to canned particulates in non-Newtonian fluids (Nylon particles suspended in aqueous carboxymethyl cellulose - CMC - solution) during fixed and free bi-axial rotation was studied in a pilot-scale, full water-immersion single-cage rotary retort. A response surface methodology was used in order to study the effect of different process parameters, including rotational speed (7-23 rpm), CMC concentration (0.0-1.0%) and retort temperature (110-130C), at five levels of each, on overall heat transfer coefficient (U) and fluid to particle heat transfer coefficient (hfp) in both rotation modes. The analysis of variance showed that the rotational speed, CMC concentration and retort temperature were significant (p < 0.05) factors for hfp in the following order: rotation speed > CMC concentration > retort temperature; however, only rotational speed and CMC concentration were significant (p < 0.05) factors for U. With an increase in rotational speed and retort temperature, there was an increase in the associated U and hfp values; however, increasing the CMC concentration resulted in the opposite. Using the numerical optimization of the Design Expert software, optimum heat transfer was found at a rotational speed of 20 rpm, CMC concentration of 0.6% and retort temperature of 126C. T-test revealed that both U and hfp were significantly (p < 0.05) higher in the free bi-axial mode as compared to the fixed axial mode of rotation.

Optimization of Instrumental Texture of Carrot and Meat Alginate Simulated Particles for Use in Thermal Processing Biological Validation Studies

Alginate-based simulated particles with spores of heat resistant microorganisms distributed in them are used in the biological validation studies, and the process lethality is usually calculated using initial and final counts. Such particles should be hard enough to save their integrity till the end of the thermal process. Also, they should not adhere to each other inside the can or to the cans inner wall. In this study, a response surface methodology was used to determine the optimum conditions that give maximum hardness and minimum adhesiveness of meat and carrot alginate fabricated particles. Sodium alginate concentration (1.5–6.5%), calcium chloride concentration (1.0–3.0%), and immersion time in the calcium chloride solution (4–44 h) were employed as factors at five levels, and the instrumental textural properties were assessed using the texture profile analysis. For each response (hardness and adhesiveness), a second-order polynomial model was developed using multiple linear regression analysis. Hardness of the fabricated particles was found to significantly increase (p < 0.05) with increasing sodium alginate concentration and immersion time in the calcium chloride solution, while calcium chloride concentration had no significant effect. On the other hand, adhesiveness (in absolute values) of the reconstituted particles increased significantly (p < 0.05) with increasing sodium alginate while the other two parameters had no significant effect. Applying the desirability function method, optimum conditions were found to be sodium alginate concentration of 4.7%, calcium chloride concentration of 2.6%, and immersion time of 32.0 and 30.8 h for carrot alginate and meat alginate fabricated particles, respectively. Fabricated particles using the optimum conditions did not show any variability in hardness values, unlike real food particles, when subjected to thermal processing. This investigation could help food processors using continuous agitation processing to fabricate firm and thermally stable reconstituted particles to be used in the biological validation studies.

Analysis of Aflatoxin M1 in Breast Milk and Its Association with Nutritional and Socioeconomic Status of Lactating Mothers in Lebanon

Aflatoxin B1 (AFB1) is the most potent of the dietary aflatoxins, and its major metabolite, aflatoxin M1 (AFM1), is frequently found in the breast milk of lactating mothers. The aim of this study was to assess the occurrence and factors associated with AFM1 contamination of breast milk collected from lactating mothers in Lebanon. A total of 111 breast milk samples were collected according to the guidelines set by the World Health Organization. Samples were analyzed with a competitive enzyme-linked immunosorbent assay between December 2015 and November 2016. A survey was used to determine the demographic and anthropometric characteristics of participating lactating mothers. Dietary habits were assessed using a semiquantitative food frequency questionnaire. Mean (±standard deviation) concentration of AFM1 in the breast milk samples was 4.31 ± 1.8 ng/L, and 93.8% of samples contained AFM1 at 0.2 to 7.9 ng/L. The mean concentration of AFM1 was significantly lower (P < 0.05) in fall and winter (4.1 ± 1.9 ng/L) than in spring and summer (5.0 ± 1.7 ng/L). None of the samples exceeded the European Commission regulation limit (25 ng/L) for infant milk replacement formula. AFM1 contamination was significantly associated (P < 0.05) with the daily consumption of white cheeses but not with the consumption of meat or cereal products. No significant association (P > 0.05) was observed between AFM1 concentrations in breast milk and anthropometric sociodemographic factors (age and level of education) or the governorate of residence of the nursing mothers. The mean AFM1 estimated daily intake was found to be 0.69 ng/day/kg of body weight. Although the incidence of AFM1 contamination was low, our first-of-its-kind study highlights the importance of conducting investigations on mycotoxin contamination in breast milk and of developing protection strategies to tackle the exposure of infants to this potent chemical hazard.

Self-reported food safety knowledge and practices of Lebanese food handlers in Lebanese households

Purpose To assess level of food safety knowledge and self-reported practices among Lebanese food handlers in Lebanese households and to identify the association between knowledge/practices and socio-demographic characteristics. Design/methodology/approach A cross-sectional study was conducted among 1500 participants from different gender, age, area of residence, income, marital status and education. They completed a questionnaire of 6 questions about demographics, and 26 questions related to knowledge and self-reported practices in terms of food handling, storage, usage of kitchen facilities and personal hygiene subgroups. SPSS v23 was used for statistical analyses. Student t test and ANOVA were conducted. Significance level of 0.05 was used. Findings On average, participants scored 55.6±16.3, 51.3±25.7, 67.4±19.3, and 89.1±16.3, on food handling, storage, usage of kitchen facilities and personal hygiene, respectively; whereas, the passing (score above 50%) rates were 64.5, 69.9, 90.5 and 99.1, respective...

Evaluation of gluten in gluten-free-labeled foods and assessment of exposure level to gluten among celiac patients in Lebanon

Abstract The aim of the study was to evaluate gluten contamination in all the gluten-free (GF)-labeled food products sold in Lebanon. Over a 2-year period, a total of 173 food samples collected from 135 brand names were analyzed. Gluten contamination was detected in 33 of 173 (19%) samples, and its content ranged between 2.5 and >80 mg kg−1. In 10 of the 173 samples (6%), the quantity of gluten exceeded the upper limit of 20 mg kg−1. Out of the 10 contaminated products, eight (80%) were locally manufactured. Among these 10 products, eight (80%) were wheat-starch-based foods. Of the 40 brand names tested twice in 2014 and 2015, 15 (38%) showed significantly (p < .05) different gluten content between the 2 years. Using a food frequency questionnaire, exposure level to gluten through the contaminated products was evaluated among 15 celiac patients. Two patients reported consuming these products more than twice per week.