Influence of Endogenous Factors of Food Matrices on Avidin–Biotin Immunoassays for the Detection of Bacitracin and Colistin in Food

(Strept)avidin–biotin technology is frequently used in immunoassay systems to improve their analytical properties. It is known from clinical practice that many (strept)avidin–biotin-based tests provide false results when analyzing patient samples with a high content of endogenous biotin. No specific investigation has been carried out regarding possible interferences from avidin (AVI) and biotin (B7) contained in food matrices in (strept)avidin–biotin-based immunoanalytical systems for food safety. Two kinds of competitive ELISAs for bacitracin (BT) and colistin (COL) determination in food matrices were developed based on conventional hapten–protein coating conjugates and biotinylated BT and COL bound to immobilized streptavidin (SAV). Coating SAV–B7–BT and SAV–B7–COL complexes-based ELISAs provided 2- and 15-times better sensitivity in BT and COL determination, corresponding to 0.6 and 0.3 ng/mL, respectively. Simultaneously with the determination of the main analytes, these kinds of tests were used as competitive assays for the assessment of AVI or B7 content up to 10 and 1 ng/mL, respectively, in food matrices (egg, infant milk formulas enriched with B7, chicken and beef liver). Matrix-free experiments with AVI/B7-enriched solutions showed distortion of the standard curves, indicating that these ingredients interfere with the adequate quantification of analytes. Summarizing the experience of the present study, it is recommended to avoid immunoassays based on avidin–biotin interactions when analyzing biosamples containing these endogenous factors or enriched with B7.

107 Quality Parameters of Pet Treats Generated from Beef Processing Co-products

By-products such as beef liver (BL) and beef heart (BH), while rich in protein, vitamins, and minerals, can be difficult products for incorporation into mixtures. Sodium alginate (SA) and calcium lactate (CL) can be used to improve structure of protein sources. The objective was to determine the quality of restructured BL and BH pet treats using ALGIN as a structure forming agent. Quality parameters assessed were pH, expressible moisture, cooking loss, and water activity of raw and dehydrated pet treats. After grinding, BL and BH, were mixed: 25%BL:75%BH, 50%BL:50%BH, and 75%BL:25%BH. The 3 BL:BH combinations were mixed with 2 dosages of ALGIN (0.5% SA + 0.425% CL, and 1% SA + 0.85% CL) to produce 6 treatments. Each treatment was then extruded into 20-mm-thick jerky slices and refrigerated at 3°C for 48 h. Samples were dehydrated at 93°C for 2.5 h for cooking loss analysis. Ten raw samples (25.4 mm × 25.4 mm) were used to measure expressible moisture, and another ten raw samples were used to measure pH. Water activity was assessed on ten raw and ten dehydrated samples. Data were analyzed with the GLIMMIX procedure of SAS and means were separated at P ≤ 0.05. Cooking loss decreased as ALGIN dosage increased in all BL and BH mixtures (P < 0.0001); however, cooking loss percentage increased as BH proportions increased (P = 0.0001). Water activity of dehydrated samples decreased as BL proportions increased (P < 0.0001), but with increasing ALGIN dosage, water activity of dehydrated treats increased (P = 0.0193). Raw pH was not affected by treatment. Expressible moisture of samples increased with increasing BL proportions (P < 0.0001) but decreased as ALGIN dosage decreased (P < 0.0001). Use of ALGIN allowed for BL and BH to be restructured into an acceptable form for use in pet treats.

Evaluation of the Energy Budget of the Fish Cyprinus Carpio in Acid Waters

The present study was focused on the influence of acid waters on the energy budget of the fish Cyprinus carpio. The experimental fish were tested in the experimental media (pH 5.0, 5.8, 6.6, and control 7.2) for 21 days for the bioenergetics evaluation. The fishes were fed by the fresh beef liver. The pH was upheld vigilantly throughout the investigation, after the experimental period, the results revealed the declined rates of food consumption (69.75 J/g/day), absorption (96.28 (J/g/day), conversion ( -30.76 Rate of energy conversion (J/g/day), and the hyper-metabolic rate (5.09 Energy metabolized KJ/animal) was observed in the fishes exposed to low pH 5.0, 5.8, and 6.6 respectively.

Effect of density and species preferences on collective choices: an experimental study on maggot aggregation behaviours

ABSTRACTCollective decisions have been extensively studied in arthropods, but they remain poorly understood in heterospecific groups. This study was designed to (1) assess the collective behaviours of blow fly larvae (Diptera: Calliphoridae) in groups varying in density and species composition, and (2) relate them to the costs and benefits of aggregating on fresh or decomposed food. First, experiments testing conspecific groups of Lucilia sericata and Calliphora vicina larvae, two species feeding at the same time on fresh carcasses, demonstrated decreases in growth and survival on rotten beef liver compared with fresh liver. However, mixing species together reduced this adverse impact of decomposition by increasing the mass of emerged adults. Second, larval groups were observed in binary choice tests between fresh and rotten liver (i.e. optimal and sub-optimal food sources). The results showed that larvae interacted with each other and that these interactions influenced their food preferences. We observed that (1) larvae were able to collectively choose the optimal food, (2) their choice accuracy increased with larval density and (3) the presence of another species induced a reversal in larval preference towards rotten food. These results highlight the ubiquity of collective decision properties in gregarious insects. They also reveal an unexpected effect of interspecific association, suggesting the colonization of new resources through a developmental niche construction.

Postmortem Changes in pH, Color, Drip Loss, and Non-Protein Nitrogen in Beef Liver and Lungs During Storage in Refrigerator

Beef offal are consumed by people in some countries specifically in Asia. Beef liver and lungs are favorite food which are used as meat in traditional food. The objective of this study was to determine the postmortem changes in pH, color, drip loss, and non-protein nitrogen (NPN) content in beef liver and lungs during storage in refrigerator (3-4 ºC) until 5 d (120 h) after slaughter. The beef liver and lungs were collected from the abattoir and transported in cool box (<7 ºC) to the laboratory within 3 hours. The samples size of beef liver and lungs were 20 for each observation time. In the laboratory the beef liver and lungs were measured directly for pH value, color (L*, a*, and b*), drip loss, and NPN content at 4 h postmortem (pm) and afterwards every beef liver sample was sliced into 5 pieces of 100-120 g and stored in chiller of 3-4 ºC. The measurement of pH, color (L*, a*, and b* values), drip loss, and NPN content were conducted at 4 h, 24 h, 48 h, 72 h, 96 h, and 120 h postmortem. Data were analyzed descriptively and by comparing the 95% confidence interval of mean of each observation. The results showed that pH, color, drip loss, and NPN content in beef lungs were higher than the values in beef liver. The pH of beef liver and lungs declines until 96 h pm and 48 h pm, respectively. The L*, a*, and b* values of beef liver and lungs increased in general during storage. Drip loss and NPN in beef liver and lungs tended to increase significantly during storage. From this study the pH value and NPN can be used to determine the freshness of beef liver and lungs.

Determination of Carcinogenic Toluena Detox Mass In Printing Industrial Workers In Surabaya

Background This study aims to calculate the intake of foods rich in CYP2E1 enzymes and glutathione to increase toluene detoxification. Methods The research design used was a cross sectional method. The research location is printing industry in Surabaya, East Java. The number of respondents was 30 workers of the printing industry. The calculated variables included body weight, work duration (years), work frequency per week (days), average workday (hours) of the respondent and benzene concentration. After all variables were obtained, respiration rate and carcinogenic detox benzene food intake per respondent were determined. Results All respondents who were at work showed benzene concentrations below the threshold value (TLV). Foods containing CYP2E1 enzyme included beef liver, salmon and fish oil while food with glutathione included grapes, avocados and asparagus. Conclusion Adequacy levels of CYP2E1 enzymes and glutathione are different and varied. The effective dose required by each respondent depends on body weight, length of work, and toluene concentration at work. In sum, the greater the toluene concentration, the greater the dietary needs which are rich in enzymes and CYP2E1 glutathione. Each respondent can choose benzene detox food depending on their needs and appetite.

Prevalence of Multidrug-Resistant Foodborne Pathogens and Indicator Bacteria from Edible Offal and Muscle Meats in Nashville, Tennessee

This study investigated the prevalence of antimicrobial-resistant bacteria in retail edible offal and muscle meats in Nashville, Tennessee. A total of 348 retail meats (160 edible offal and 188 muscle) were analyzed for Salmonella enterica serovar, Campylobacter, Escherichia coli, E. coli O157:H7, and enterococci. Bacteria was identified using biochemical and PCR methods. Salmonella enterica serovar (4.4% and 4.3%), Campylobacter (1.9% and 1.1%), E. coli (79.4% and 89.4%), and enterococci (88.1% and 95.7%) was detected in offal and muscle meats, respectively. Chicken liver (9.7%) was most frequently contaminated with Salmonella enterica serovar, followed by ground chicken (6.9%) and chicken wings (4.2%). No Salmonella enterica serovar was detected in beef liver, beef tripe, and ground beef. The prevalence of Campylobacter was 6.9%, 2.3%, and 1.4% in beef liver, ground beef, and ground chicken, respectively. None of the meats were positive for E. coli O157:H7. Resistance of isolates was significantly (p < 0.05) highest in erythromycin (98.3%; 99.1%), followed by tetracycline (94%; 98.3%), vancomycin (88.8%; 92.2%) as compared to chloramphenicol (43.1%; 53.9%), amoxicillin/clavulanic (43.5%; 45.7%), and ciprofloxacin (45.7%; 55.7%) in offal and muscle meats, respectively. Imipenem showed the lowest resistance (0%; 0.9%). A total of 41 multidrug-resistant patterns were displayed. Edible offal could be a source of antibiotic-resistant bacteria.

Dietary Effects on the Development of Calliphora dubia and Chrysomya rufifacies (Diptera: Calliphoridae): Implications for Postmortem Interval

Forensic entomology relies on insect development data generated within a laboratory setting in the estimation of minimum postmortem interval (mPMI). The methodologies used to produce these data vary considerably within the field and there is no accepted standard approach to laboratory rearing of forensically relevant species. A wide range of rearing media are used across published studies, including different species of animal and types of tissue (e.g., muscle and liver). Differing methodologies, particularly rearing diet, can introduce considerable variation into the baseline data upon which forensic estimates of the mPMI are calculated. Consequently, research establishing a widely available, standard and/or optimal, rearing medium for blow fly development for forensic application is desirable. This study examined dietary effects on the development of two forensically relevant blow fly species: Calliphora dubia Macquart, 1855, and Chrysomya rufifacies Macquart 1842 (Diptera: Calliphoridae). Larvae of both species were reared on pork liver, pork mince, pork loin, beef liver, beef mince, and guinea pig carcass under two constant temperature regimes (24 ± 1°C and 30 ± 1°C; 70 ± 10% humidity; 12-h/12-h photoperiod) to assess the influence of temperature on developmental response to diet. Fundamental developmental data pertaining to both species are reported. Developmental response to diet was species-specific and influenced by temperature with indication that the optimal temperature for C. dubia development is below 30°C. Pork mince was the most appropriate dietary standard of the rearing media investigated for the formulation of forensic development data for both species investigated.