Optimization of fermentation processes requires monitoring the species composition of starter cultures and their growth during fermentation. Most starter cultures contain closely related species. Nowadays, high-resolution melting (HRM) analysis is extensively used for multiplex identification of closely related species. In the present paper, we applied real-time polymerase chain reaction (PCR) with HRM analysis for the detection and differentiation of Lactobacillus sakei and L. curvatus. A primer pair was selected for the site of the rpoA gene of Lactobacillus spp. Eleven starter cultures and fifteen fermented sausages with a known bacterial composition were successfully tested using real-time PCR with HRM analysis with the developed primer pair.
A total of 112 burger patties (35 beef burger patties, 39 chicken burger patties and 38 fish burger patties) which are commercially available at retail level were investigated for the presence and number of Listeria monocytogenes. These samples were analyzed using MPN-PCR method and conventional culturing methods. L. monocytogenes was detected in 33.3% of chicken burger patties, 22.9% of beef patties, and 10.5% of fish patty samples. From all contaminated raw burger patties, the estimated count of L. monocytogenes was ranged from 3 to 75 MPN/g. The results suggest that burger act as a potential source of listeriosis if the contaminated burger patty is consumed without adequate cooking. The risk associated with consumption of these samples was found to be high particularly for processed food at retail level in Malaysia. Therefore, food manufacturers play an important role in monitoring the manufacturing process and conduct a periodical surveillance on microbiological quality assessment on the processing plants. Besides, there is a need to increase awareness of consumers and food handlers to practice proper cooking of the burger patties before the point of consumption, to reduce the risk of listeria infection.
The objective of this study was to evaluate the effects of using tapioca and sago flours with or without egg white powder (EWP) on the physicochemical and sensory properties of duck sausages. There was significant increase (P0.05) in hardness and cohesiveness attributes among all the samples examined but significant differences (P
This study was focused on the effect of incorporation of oyster mushroom, Pleurotus sajor- caju (PSC) powder to partially replace chicken meat in frankfurters on nutritional composition, β-glucan content and textural properties. The frankfurters were formulated with either 0 (control), 2, 4 or 6% of PSC powder. The results show control chicken frankfurter had the highest fat content (11.60%) while 6% PSC frankfurter had the lowest value (10.74%). In other nutrient, ash, moisture and carbohydrate content in all samples ranged from 1.55 to 1.92%, 59.36 to 61.98% and 8.84 to 13.09%, respectively. Apparently, total dietary fiber of chicken frankfurter was increased in line with the levels of PSC powder (0.08 - 6.20%). All samples recorded β-glucan in the range from 0.16 to 1.43%, except for control sample. The texture profile showed that both adhesiveness and cohesiveness attributes were not significantly different among all mushroom-based frankfurters. However, frankfurter added with 6% mushroom was more cohesive and springier than the control formulation. In summary, partial replacement of chicken meat with PSC powder resulted in enhancement of dietary fibres up to 6.20% and β-glucan up to 14.30% significantly, lowering fat content but unchanged adhesiveness and cohesiveness attributes. Therefore, PSC powder can be considered to be used as an alternative functional ingredient to improve nutritional values of processed food products.
The influence of superheated steam cooking on fat and fatty acid composition of chicken sausage were investigated at various temperatures (150, 200, and 250°C) with different time domains (2-6 min). It has been found that the fat content of raw sample was higher than that of all cooked samples. The total fat content of cooked sample, showed a linear decreasing with time at all investigated temperatures. Superheated steam produce changes in saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA) in which their values were found to decrease in cooked samples. When different cooking conditions (temperature, time) were applied, the fatty acids were decreased as the time and temperature increased. The PUFA and MUFA were less prone to decrease at 150°C, while at this temperature there was a remarkable loss in SFA content. This cooking method considerably reduced the level of fat and SFA which have a positive effect on health. In addition it could imply a great choice for consumers to choose the healthier technique for cooking food.
Adzuki bean is high in protein and fiber with a potential to be used as meat extender and fat replacer in the meat product. Replacement of both the corn flour and fat with different percentages of adzuki beans flour (ABF) has successfully produced acceptable reduced fat meatballs. Meatballs with 100% (w/w) ABF replacement exhibited highest cooking yield and higher moisture content compared to meatballs without the flour, which indicates its ability to bind water. Increasing the ABF content also increased the hardness and chewiness of the meatballs, whilst decreasing their lightness and yellowness. Replacing the corn flour and fat contents with ABF has obviously decreased the fat and calorie contents of the meatballs, yet their protein and carbohydrate contents remained the same compared to control. The sensory test revealed that meatball samples with 25% (w/w) and 50% (w/w) ABF showed no significant difference compared to control but received highest overall acceptability among the panelists. This indicates that replacement of corn flour and fat with ABF especially at 50% (w/w) in the production of reduced fat meatballs resulted with better physicochemical properties and acceptable sensory compared to original meatballs.
Pork and bovine collagen incorporated into meat products showed promising
functional properties as food ingredients but has the halal issue. This study
investigated the effect of incorporating fish collagen hydrolysate (FCH) as a fat replacer
in buffalo patties in terms of proximate values, texture and colour properties. There
were five different formulations including a control (10% fat, 0% FCH), A (7.5% fat, 2.5%
FCH), B (5% fat, 5% FCH), C (2.5% fat, 7.5% FCH), and D (0% fat, 10% FCH). There were
no significant differences (p>0.05) between all formulations in terms of cooking yield,
shrinkage, water-holding capacity, and pH value. The sensory test showed no
significant difference (p>0.05) between all formulations in terms of colour,
appearance, juiciness, aroma, and overall acceptability, while sample D with 10% FCH
had significantly lower (p
Extensive use of synthetic-based polymer plastic as packaging medium to pack food products has led to serious environmental problems due to their total non-biodegradability property. The stability of nutritional composition and physical traits of chicken patties containing oyster mushroom packed with biodegradable and non-degradable packaging materials were studied. The chicken patties containing oyster mushroom were packed with either biodegradable plastic (BP), paper box (PB) or non-biodegradable high density polyethylene (HDPE). Generally, there were no significant (P>0.05) different in all nutrient analyzed except for carbohydrate after 6 months of storage for chicken patties packed with different types of packaging. The chicken burger packed with both BP and PB packagings were able to retain the moisture and fat without jeopardizing the diameter reduction and cooking yield during storage. There were no differences in all nutrient analyzed after 6 months of storage of chicken patties packed with either biodegradable packagings (BP and PB) or non-degradable packaging. In addition, frozen storage does not significantly affect the concentration of of β-glucan in both BP and PB packagings. In summary, these results indicate that biodegradable packagings applied in packing chicken patty frozen for 6 months were effective in controlling the microbial growth and provide wholesomeness and safety to the chicken patty containing oyster mushroom.
Listeria monocytogenes (L. monocytogenes) is a serious food-borne pathogen for immunocompromised individuals. L. monocytogenes is capable of producing biofilm on the surface of food processing lines and instruments. The biofilm transfers contamination to food products and impose risk to public health. Transfers contamination to food products, and impose risk hazard to public health. The aim of this study was to investigate biofilm producing ability of L. monocytogenes isolates. Microtitre assay was used to measure the amount of biofilm production by ten L. monocytogenes isolates from minced chicken / meat, sausages and burgers. Results showed that all 10 L. monocytogenes isolates were able to form biofilm after 24 h at 20˚C on polystyrene surface (the common surface in food industries). Some strains were capable of forming biofilm more than the others. All strains showed a slight raise in the quantities of attached cells over 48 and 72 h. L. monocytogenes strains isolated from minced chicken, minced meat and burgers were better biofilm-producers comparing to the strains isolated from sausages.
Food falsification has direct impact on public health, religious faith, fair-trades and wildlife. For the first time, here we described a multiplex polymerase chain reaction assay for the accurate identification of five meat species forbidden in Islamic foods in a single assay platform. Five pairs of species-specific primers were designed targeting mitochondrial ND5, ATPase 6, and cytochrome b genes to amplify 172, 163, 141, 129 and 108 bp DNA fragments from cat, dog, pig, monkey and rat meats, respectively. All PCR products were identified in gel-images and electrochromatograms obtained from Experion Bioanalyzer. Species-specificity checking against 15 important meat and fish and 5 plant species detected no cross-species amplification. Screening of target species in model and commercial meatballs reflected its application to detect target species in process foods. The assay was tested to detect 0.01-0.02 ng DNA under raw states and 1% suspected meats in meatball formulation.
The nutritional properties of surimi-like materials produced from spent duck meat processed conventionally (CDS) and processed with acid and alkaline solubilization (ACDS and ALDS, respectively) were studied. The essential amino acids (EAAs) content was significantly higher (p meat, which has potential for human food uses.
Wider availability but lack of legal market trades has given feline meat a high potential for use as an adulterant in common meat and meat products. However, mixing of feline meat or its derivatives in food is a sensitive issue, since it is a taboo in most countries and prohibited in certain religions such as Islam and Judaism. Cat meat also has potential for contamination with of severe acute respiratory syndrome, anthrax and hepatitis, and its consumption might lead to an allergic reaction. We developed a very short-amplicon-length (69 bp) PCR assay, authenticated the amplified PCR products by AluI-restriction digestion followed by its separation and detection on a lab-on-a-chip-based automated electrophoretic system, and proved its superiority over the existing long-amplicon-based assays. Although it has been assumed that longer DNA targets are susceptible to breakdown under compromised states, scientific evidence for this hypothesis has been rarely documented. Strong evidence showed that shorter targets are more stable than the longer ones. We confirmed feline-specificity by cross-challenging the primers against 10 different species of terrestrial, aquatic and plant origins in the presence of a 141-bp site of an 18S rRNA gene as a universal eukaryotic control. RFLP analysis separated 43- and 26-bp fragments of AluI-digest in both the gel-image and electropherograms, confirming the original products. The tested detection limit was 0.01% (w/w) feline meat in binary and ternary admixed as well as meatball matrices. Shorter target, better stability and higher sensitivity mean such an assay would be valid for feline identification even in degraded specimens.
The volatile compounds of pork, other meats and meat products were studied using an electronic nose and gas chromatography mass spectrometer with headspace analyzer (GCMS-HS) for halal verification. The zNose™ was successfully employed for identification and differentiation of pork and pork sausages from beef, mutton and chicken meats and sausages which were achieved using a visual odor pattern called VaporPrint™, derived from the frequency of the surface acoustic wave (SAW) detector of the electronic nose. GCMS-HS was employed to separate and analyze the headspace gasses from samples into peaks corresponding to individual compounds for the purpose of identification. Principal component analysis (PCA) was applied for data interpretation. Analysis by PCA was able to cluster and discriminate pork from other types of meats and sausages. It was shown that PCA could provide a good separation of the samples with 67% of the total variance accounted by PC1.
The present investigation focuses on the textural properties, sensory attributes and color changes of beef frankfurter, beef ham and meat-free sausage produced by different levels of bleached tomato pomace. The texture and color profile were performed using an instrumental texture analyzer and colorimeter. The findings indicated that tomato pomace-added sausages had higher water holding capacity (WHC) compared to that of commercial samples. The frankfurters containing 5 and 7% (w/w) tomato pomace had the highest redness (a*), chroma (C*) and color differences (ΔE) values, while the meat-free sausages containing 7% (w/w) tomato pomace had significant (p<0.05) values for lightness (L*) and yellowness (b*). Furthermore, there were no significant (p>0.05) color differences between beef ham samples (with and without tomato pomace). A significant progression in the textural hardness and chewiness of systems containing tomato pomace was observed as well as higher sensory scores by panelists. According to sensorial evaluations, bleached tomato pomace improved the consumer acceptability and preference.
A polymerase chain reaction (PCR) assay for the assessment of dog meat adulteration in meatballs was developed. The assay selectively amplified a 100-bp region of canine mitochondrial cytochrome b gene from pure, raw, processed and mixed backgrounds. The specificity of the assay was tested against 11 animals and 3 plants species, commonly available for meatball formulation. The stability of the assay was proven under extensively autoclaving conditions that breakdown target DNA. A blind test from ready to eat chicken and beef meatballs showed that the assay can repeatedly detect 0.2% canine meat tissues under complex matrices using 0.04 ng of dog DNA extracted from differentially treated meatballs. The simplicity, stability and sensitivity of the assay suggested that it could be used in halal food industry for the authentication of canine derivatives in processed foods.
In a commercial oyster mushroom farm, from 300 g of the total harvest, only the cap and stem of the fruiting body parts are harvested (200 g) while the unused lower section called fruiting-body-base (FBB) is discarded (50 g). A new antioxidative FBB flour (FBBF) conversion to mixed-ratio chicken patty was recently developed which converts 16.67% of FBB into an edible flour. At the initial stage, pretreatments of FBBF were optimized at particle size (106 µm) and citric acid concentration (0.5 g/100 mL) to improve flour antioxidant responses. Such pretreatments boosted total phenolic content (2.31 ± 0.53 mg GAE/g) and DPPH (51.53 ± 1.51%) of pretreated FBBF. Mixed-ratio chicken patty containing FBBF (10%, 20%, 30%) significantly (P
Cattle, buffalo, and porcine materials are widely adulterated, and their quantification might safeguard health, religious, economic, and social sanctity. Recently, conventional polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (RFLP) assays have been documented but they are just suitable for identification, cannot quantify adulterations. We described here a quantitative tetraplex real-time PCR assay with TaqMan Probes to quantify contributions from cattle, buffalo, and porcine materials simultaneously. Amplicon-sizes were very short (106-, 90-, and 146-bp for cattle, buffalo, and porcine) because longer targets could be broken down, bringing serious ambiguity in molecular diagnostics. False negative detection was eliminated through an endogenous control (141-bp site of eukaryotic 18S rRNA). Analysis of 27 frankfurters and 27 meatballs reflected 84-115% target recovery at 0.1-10% adulterations. Finally, a test of 36 commercial products revealed 71% beef frankfurters, 100% meatballs, and 85% burgers contained buffalo adulteration, but no porcine was found in beef products.
Authentication of meat products is critical in the food industry. Meat adulteration may lead to religious apprehensions, financial gain and food-toxicities such as meat allergies. Thus, empirical validation of the quality and constituents of meat is paramount. Various analytical methods often based on protein or DNA measurements are utilized to identify meat species. Protein-based methods, including electrophoretic and immunological techniques, are at times unsuitable for discriminating closely related species. Most of these methods have been replaced by more accurate and sensitive detection methods, such as DNA-based techniques. Emerging technologies like DNA barcoding and mass spectrometry are still in their infancy when it comes to their utilization in meat detection. Gold nanobiosensors have shown some promise in this regard. However, its applicability in small scale industries is distant. This article comprehensively reviews the recent developments in the field of analytical methods used for porcine identification.
Beef, buffalo, and pork adulteration in the food chain is an emerging and sensitive issue. Current molecular techniques to authenticate these species depend on polymerase chain reaction (PCR) assays involving long and single targets which break down under natural decomposition and/or processing treatments. This novel multiplex polymerase chain reaction-restriction fragment length polymorphism assay targeted two different gene sites for each of the bovine, buffalo, and porcine materials. This authentication ensured better security, first through a complementation approach because it is highly unlikely that both sites will be missing under compromised states, and second through molecular fingerprints. Mitochondrial cytochrome b and ND5 genes were targeted, and all targets (73, 90, 106, 120, 138, and 146 bp) were stable under extreme boiling and autoclaving treatments. Target specificity and authenticity were ensured through cross-amplification reaction and restriction digestion of PCR products with AluI, EciI, FatI, and CviKI-1 enzymes. A survey of Malaysian frankfurter products revealed rampant substitution of beef with buffalo but purity in porcine materials.
Listeria spp. are ubiquitous in nature and can be found in various environmental niches such as soil, sewage, river water, plants, and foods, but the most frequently isolated species are Listeria monocytogenes and Listeria innocua. In this study, the presence of Listeria spp. in raw chicken meat and chicken-related products sold in local markets in Klang Valley, Malaysia was investigated. A total of 44 Listeria strains (42 L. innocua and 2 L. welshimeri) were isolated from 106 samples. Antibiotic susceptibility tests of the L. innocua strains revealed a high prevalence of resistance to clindamycin (92.9%), ceftriaxone (76.2%), ampicillin (73.8%), tetracycline (69%), and penicillin G (66.7%). Overall, 31 L. innocua and 1 L. welshimeri strain were multidrug resistant, i.e., nonsusceptible to at least one antimicrobial agent in three or more antibiotic classes. The majority of the L. innocua strains were placed into five AscI pulsogroups, and overall 26 distinct AscI pulsotypes were identified. The detection of multidrug-resistant Listeria strains from different food sources and locations warrants attention because these strains could serve as reservoirs for antimicrobial resistance genes and may facilitate the spread and emergence of other drug-resistant strains.