Laser-Induced Graphene Electrodes Modified with a Molecularly Imprinted Polymer for Detection of Tetracycline in Milk and Meat

Tetracycline (TC) is a widely known antibiotic used worldwide to ‘’treat animals. Its residues in animal-origin foods cause adverse health effects to consumers. Low-cost and real-time measuring systems of TC in food samples are, therefore, extremely needed. In this work, a three-electrode sensitive and label-free sensor was developed to detect TC residues from milk and meat extract samples, using CO2 laser-induced graphene (LIG) electrodes modified with gold nanoparticles (AuNPs) and a molecularly imprinted polymer (MIP) used as a synthetic biorecognition element. LIG was patterned on a polyimide (PI) substrate, reaching a minimum sheet resistance (Rsh) of 17.27 ± 1.04 Ω/sq. The o-phenylenediamine (oPD) monomer and TC template were electropolymerized on the surface of the LIG working electrode to form the MIP. Surface morphology and electrochemical techniques were used to characterize the formation of LIG and to confirm each modification step. The sensitivity of the sensor was evaluated by differential pulse voltammetry (DPV), leading to a limit of detection (LOD) of 0.32 nM, 0.85 nM, and 0.80 nM in buffer, milk, and meat extract samples, respectively, with a working range of 5 nM to 500 nM and a linear response range between 10 nM to 300 nM. The sensor showed good LOD (0.32 nM), reproducibility, and stability, and it can be used as an alternative system to detect TC from animal-origin food products.

Removal of Mixed-Species Biofilms Developed on Food Contact Surfaces with a Mixture of Enzymes and Chemical Agents

Sanicip Bio Control (SBC) is a novel product developed in Mexico for biofilms’ removal. The aims of this study were to evaluate (i) the removal of mixed-species biofilms by enzymatic (protease and α-amylase, 180 MWU/g) and chemical treatments (30 mL/L SBC, and 200 mg/L peracetic acid, PAA) and (ii) their effectiveness against planktonic cells. Mixed-species biofilms were developed on stainless steel (SS) and polypropylene B (PP) in whole milk (WM), tryptic soy broth (TSB) with meat extract (TSB+ME), and TSB with chicken egg yolk (TSB+EY) to simulate the food processing environment. On SS, all biofilms were removed after treatments, except the enzymatic treatment that only reduced 1–2 log10 CFU/cm2, whereas on PP, the reductions ranged between 0.59 and 5.21 log10 CFU/cm2, being the biofilms developed in TSB+EY being resistant to the cleaning and disinfecting process. Higher reductions in microbial load on PP were reached using enzymes, SBC, and PAA. The employed planktonic cells were markedly more sensitive to PAA and SBC than were the sessile cells. In conclusion, biofilm removal from SS can be achieved with SBC, enzymes, or PAA. It is important to note that the biofilm removal was strongly affected by the food contact surfaces (FCSs) and surrounding media.

Identification of Secondary Metabolites and Proximate Analysis of Golden Apple Snails (Pomacea canaliculata L.) Meat Extract

The growth of golden apple snails is very rapid and causes losses of paddy production. Therefore snails are also called pest, especially agricultural pest. Control of golden apple snails can be done by physical hand sorting and then processed into animal feed. Based on research golden apple snails proven have good nutritional content. Efforts to use golden apples nails pets become useful things such as animal feed is a sustainable conservation. Therefore, this study aims to carry out secondary metabolites identification, proximate testing, and antioxidant content of golden apple snails as an initial reference for the basic ingredients of animal feed manufacturing. The method use is hand sorting of golden apple snails at the research location, then brought to the laboratory to carry out the process of secondary metabolites identification, proximate testing, and antioxidant analysis. The results showed a golden apple snails (Pomacea canaliculata L.) extract containing active compunds of alkaloids, flavonoids, tannins and polyphenols, steroids, and glycoside. Proximate analysis showed that golden apple snails extract had a high protein content of 40,83% compared to carbohydrates and fats. These findings suggested that golden apple snailsmeat extract has the potential to be further utilized as an alternative feed for Pangasius sp.Keywords: golden apple snails. Pangasius sp., proximate testing, secondary metabolites.

Production of spiculisporic acid by Talaromyces trachyspermus in fed-batch bioreactor culture

Spiculisporic acid (SA) is a fatty acid-type biosurfactant with one lactone ring and two carboxyl groups. It has been used in metal removers and cosmetics, because of its low propensity to cause irritation to the skin, its anti-bacterial properties, and high surface activity. In the present study, we report an effective method for producing SA by selecting a high-producing strain and investigating the effective medium components, conditions, and environments for its culture. Among the 11 kinds of Talaromyces species, T. trachyspermus NBRC 32238 showed the highest production of a crystalline substance, which was determined to be SA using NMR. The strain was able to produce SA under acidic conditions from hexoses, pentoses, and disaccharides, with glucose and sucrose serving as the most appropriate substrates. Investigation of nitrogen sources and trace metal ions revealed meat extract and FeCl3 as components that promoted SA production. Upon comparing the two types of cultures with glucose in a baffle flask or aeration bioreactor, SA production was found to be slightly higher in the flask than in the reactor. In the bioreactor culture, sucrose was found to be an appropriate substrate for SA production, as compared to glucose, because with sucrose, the lag time until the start of SA production was shortened. Finally, fed-batch culture with sucrose resulted in 60 g/L of SA, with a total yield of 0.22 g SA/g sucrose and a productivity of 6.6 g/L/day.

Production of spiculisporic acid by Talaromyces trachyspermus in fed-batch bioreactor culture

Spiculisporic acid (SA) is a fatty acid-type biosurfactant with one lactone ring and two carboxyl groups. It has been used in metal removers and cosmetics, because of its low propensity to cause irritation to the skin, its antibacterial properties, and high surface activity. In the present study, we report an effective method for producing SA by selecting a high-producing strain and investigating the effective medium components, conditions, and environments for its culture. Among the 11 kinds of Talaromyces species, T. trachyspermus NBRC 32238 showed the highest production of a crystalline substance, which was determined to be SA using NMR. The strain was able to produce SA under acidic conditions from hexoses, pentoses, and disaccharides, with glucose and sucrose serving as the most appropriate substrates. Investigation of nitrogen sources and trace metal ions revealed meat extract and FeCl3 as components that promoted SA production. Upon comparing the two types of cultures with glucose in a baffle flask or aeration bioreactor, SA production was found to be slightly higher in the flask than in the reactor. In the bioreactor culture, sucrose was found to be an appropriate substrate for SA production, as compared to glucose, because with sucrose, the lag time until the start of SA production was shortened. Finally, fed-batch culture with sucrose resulted in 60 g/L of SA, with a total yield of 0.22 g SA/g sucrose and a productivity of 6.6 g/L/d.

Antiproliferative effects of fresh water crab hemolymph and meat extract on breast cancer cell line

Background and aims: Despite the advances in drugs, side effects of chemotherapy drugs continue to exist. Therefore, more attention has been paid to the compounds derived from medicinal herbs and aquatic organisms. This study aimed to investigate the effect of freshwater crab hemolymph and meat extract on breast cancer (BC) cell line (4T1). Methods: After isolation of freshwater crab hemolymph and meat extract, protein concentration and total antioxidant capacity were analyzed by bicinchoninic acid (BCA) and cupric reducing antioxidant capacity (CUPRAC) methods. The 4T1 cells and bone marrow mesenchymal stem cells (BMSCs) were treated with crab hemolymph (1, 2, 10 mg/mL) and meat extract (0.1, 0.2 and 1 mg/mL), and cell survival was analyzed using 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (MTT) at 48 and 72 hours. Nitric oxide (NO) secretion was measured by Griess method. Data were analyzed using one-way analysis of variance (ANOVA). Results: Protein concentration of 23.25 mg/mL was shown in crab hemolymph, and 2.3 mg/mL in meat extract. Total antioxidant capacity was reported as 1.036 µM/mL and 1.104 µM/mL in crab hemolymph and meat extract, respectively. Cell survival in the 4T1 cells was decreased in a dose- and time-dependent manner (P≤0.001). NO secretion of 4T1 cells was decreased after treatment with different concentrations of crab hemolymph and meat extract at 48 and 72 hours. Cellular growth was observed in BMSCs after treatment with different concentrations of crab hemolymph and meat extract at 48 and 72 hours. Conclusion: Since crab hemolymph and meat extract have protein and antioxidant activities, they can have anti-cancer effects on 4T1 cells.

The Removal of Meat Exudate and Escherichia coli from Stainless Steel and Titanium Surfaces with Irregular and Regular Linear Topographies

Bacterial retention and organic fouling on meat preparation surfaces can be influenced by several factors. Surfaces with linear topographies and defined chemistries were used to determine how the orientation of the surface features affected cleaning efficacy. Fine polished (irregular linear) stainless steel (FPSS), titanium coated fine polished (irregular linear) stainless steel (TiFP), and topographically regular, linear titanium coated surfaces (RG) were fouled with Escherichia coli mixed with a meat exudate (which was utilised as a conditioning film). Surfaces were cleaned along or perpendicular to the linear features for one, five, or ten wipes. The bacteria were most easily removed from the titanium coated and regular featured surfaces. The direction of cleaning (along or perpendicular to the surface features) did not influence the amount of bacteria retained, but meat extract was more easily removed from the surfaces when cleaned in the direction along the linear surface features. Following ten cleans, there was no significant difference in the amount of cells or meat exudate retained on the surfaces cleaned in either direction. This study demonstrated that for the E. coli cells, the TiFP and RG surfaces were easiest to clean. However, the direction of the clean was important for the removal of the meat exudate from the surfaces.

DETERMINATION OF THE OPTIMUM CONDITIONS FOR BIOSURFACTANT PRODUCTION BY LOCAL ISOLATE OF LACTOBACILLUS PLANTARUM AND EVALUATE ITS ANTIMICROBIAL ACTIVITY

Eighty five local isolates of Lactobacillus sp. which were isolated from different sources and identified by biochemical test then subjected to the primary and secondary screening processes to select the active Lactobacillus sp. isolate for biosurfactant production. Among the isolates screened, twenty six isolates with maximum for tests in primary screening were selected for secondary screening. It has been found that Lactobacillus sp. ADK2 had the highest productivity of the biosurfactant. The selected isolate with highest level of biosurfactant activity was identified as Lactobacillus plantarum ADK2 according to PCR technique. The optimum conditions of biosurfactant production by isolate Lactobacillus plantarum ADK2 using submerged fermentation were obtained in the synthetic mineral salt medium (MSM) and natural BCDFTM medium the best production medium separately, 1.5% (lactose and egg) as the best carbon source, 2% meat extract and 3.5% Pease as nitrogen source, temperature 30 °C for two media and pH 5 with pH 3 in MSM and BCDFTM respectively, after 96 hr and 72 hr in MSM and BCDFTM respectively of incubation period.