Recently, cultivation of high-yielding hybrid maize varieties has revolutionized maize production in Pakistan. Analyses of nutritional traits and aflatoxin (AF) contamination in these varieties can aid in the identification of susceptible and resistant varieties, particularly for cultivation in the Pakistani agro-climatic environment. Five spring maize varieties-Pioneer, Neelam, DK-919, Desi, and Hi-maize-were selected for analyses of their nutritional, tocopherol, and AF contents. Protein, carbohydrate, oil, ash, fiber, and moisture contents ranged between 8.7 and 10.8%, 68 and 71%, 3.72 and 5.56%, 1.09 and 1.81%, 1.1 and 3.1%, and 11.7 and 14.2%, respectively. Tocopherol levels in selected varieties were in the range of 461 to 1,430 μg/g. Hi-maize exhibited significantly higher protein and tocopherol contents than the other varieties, indicating its better suitability for feed and silage applications. The highest mean level of total AFs, 14.5 ± 0.12 μg/kg, was found in Desi, and results showed that the most dominant AF found in the maize varieties was AFB1. Furthermore, the results showed that the higher the level of tocopherol, the lower the concentration of total AFs and vice versa in maize varieties. The results can be used to investigate additional susceptible maize varieties that are resistant to fungal attack.
Two hundred ten samples of selected vegetables (okra, pumpkin, tomato, potato, eggplant, spinach, and cabbage) from Faisalabad, Pakistan, were analyzed for the analysis of heavy metals: cadmium (Cd), lead (Pb), arsenic (As), and mercury (Hg). Inductively coupled plasma optical emission spectrometry was used for the analysis of heavy metals. The mean levels of Cd, Pb, As, and Hg were 0.24, 2.23, 0.58, and 7.98 mg/kg, respectively. The samples with Cd (27%), Pb (50%), and Hg (63%) exceeded the maximum residual levels set by the European Commission. The mean levels of heavy metals found in the current study are high and may pose significant health concerns for consumers. Furthermore, considerable attention should be paid to implement comprehensive monitoring and regulations.
Aflatoxins (AFs), ochratoxin A (OTA) and zearalenone (ZEN) were analysed in 237 breakfast cereal samples collected from central areas of Punjab, Pakistan. According to the results, 41% of the samples were found contaminated with AFs, out of which 16% and 8% samples were found to be above the European Union (EU) maximum content for AFB1 and total AFs, respectively. About 48% samples were found contaminated with OTA and 30% samples were found to be above the EU maximum content. The results have shown that 53% samples of breakfast cereals were found contaminated with ZEN and 8% samples were found to be above the permissible limit of EU. The highest mean level of AFB1 and total AFs were found in semolina i.e. 3.60 and 4.55 μg/kg, respectively. Similarly, semolina was the highest contaminated breakfast cereal for OTA (3.90 μg/kg), while cornflakes (brand B) was found highest contaminated with ZEN (13.45 μg/kg).
This paper reviews the application of various modes of solid-phase microextraction (SPME) for the analysis of pesticide residues in fruits and vegetables. SPME is a simple extraction technique that eliminates the use of solvent, and it is applied for the analysis of both volatile and nonvolatile pesticides. SPME has been successfully coupled to both GC and LC. The coupling with GC has been straightforward and requires little modification of existing equipment, but interfacing with LC has proved challenging. The external standard calibration technique is widely used for quantification, while standard addition and internal or surrogate standards are mainly used to account for matrix effects. All parameters that affect the extraction of pesticide residues from fruits and vegetables, and therefore need to be optimized, are also reviewed. Details of the characteristics of analytical procedures and new trends in fiber production using sol-gel technology and molecularly imprinted polymers are discussed.
Food quality and food safety are major challenges affecting agricultural and industrial aspects of production. Many contaminants from different sources contaminate foods and drinks, leading to disastrous health problems like gene mutations and cancer. Previously, many different methods have been used for the analysis of these contaminants. Liquid-liquid extraction (LLE) has been the most well-known conventional technique used, but its limitations are its tediousness, time required, and the use of large quantities of toxic organic solvents. These limitations have led to the search for other, efficient techniques that are more environmentally friendly. Hence, this review highlights recent advances in liquid-phase (single-drop, hollow fiber, and dispersive liquid-liquid) microextraction procedures for food and drink analyses. Such modifications can be justified for solving limitations associated with the traditional LLE method. The objective of this review is to serve as a reference platform for providing effective management tools for solving problems of pollution, clean-up, and control of food quality and safety globally.
This review presents the application of carbon nanotubes as sorbent materials in the analysis of pesticide residues in fruits and vegetables. The advantages, limitations, and challenges of carbon nanotubes, with respect to their use in analytical chemistry, are presented. The efficiency of their application as extraction sorbent materials (in terms of LOD, LOQ, linearity, relative recovery, and RSD) in SPE, solid-phase microextraction, multi-plug filtration clean-up, matrix solid-phase dispersion, and the quick, easy, cheap, effective, rugged and safe method is reported. The synthesis, functionalization, purification, and characterization methods of carbon nanotubes are also discussed.
The purpose of this study was to investigate the biosafety of Vibrio parahaemolyticus in raw salad vegetables at wet market and supermarket in Malaysia. A combination of Most Probable Number - Polymerase Chain Reaction (MPN-PCR) method was applied to detect the presence of V. parahaemolyticus and to enumerate their density in the food samples. The study analyzed 276 samples of common vegetables eaten raw in Malaysia (Wild cosmos = 8; Japanese parsley = 21; Cabbage = 30; Lettuce = 16; Indian pennywort = 17; Carrot = 31; Sweet potato = 29; Tomato = 38; Cucumber = 28; Four winged bean = 26; Long bean = 32). The samples were purchased from two supermarkets (A and B) and two wet markets (C and D). The occurrence of V. parahaemolyticus detected was 20.65%, with higher frequency of V. parahaemolyticus in vegetables obtained from wet markets (Wet market C = 27.27%Wet Market D = 32.05%) compared to supermarkets (Supermarket A = 1.64%; Supermarket B = 16.67%). V. parahaemolyticus was most prevalent in Indian pennywort (41.18%). The density of V. parahaemolyticus in all the samples ranged from <3 up to >2400 MPN/g, mostly <3 MPN/g concentration. Raw vegetables from wet markets contained higher levels of V. parahaemolyticus compared to supermarkets. V. parahaemolyticus were present in raw vegetables although in low numbers. The results suggest that raw vegetables act as a transmission route for V. parahaemolyticus. This study will be the first biosafety assessment of V. parahaemolyticus in raw vegetables in Malaysia.
A total of 126 local and imported samples of commercial white and black pepper in Malaysia were analysed for aflatoxins B1, B2, G1 and G2 (AFB1, AFB2, AFG1, AFG2) content using high-performance liquid chromatography (HPLC) with a fluorescence detector (FD). An acetonitrile-methanol-water (17 : 29 : 54; v/v) mixture was used as a mobile phase and clean-up was using an immunoaffinity column (IAC). Seventy out of 126 (55.5%) samples were contaminated with total aflatoxins, although only low levels of aflatoxins were found ranging from 0.1 to 4.9 ng g(-1). Aflatoxin B1 showed the highest incidence of contamination and was found in all contaminated samples. There was a significant difference between type of samples and different brands (p < 0.05). The results showed black peppers were more contaminated than white peppers.
After the incidences of induction of aristolochic acid nephropathy after consumption of herbal weight loss preparations that accidentally contained aristolochic acids (AAs), several countries defined national restrictions on the presence of AAs in food, including plant food supplements (PFS) and herbal products. This study investigates whether the risks associated with exposure to AAs via PFS and herbal products are at present indeed negligible. Data reported in literature on AA levels in PFS and other herbal products and also obtained from a new series of PFS in the present study were used to calculate the estimated daily intakes (EDIs) and corresponding margins of exposure (MOEs). Available literature data revealed that 206 out of 573 samples were found to contain aristolochic acid I (AAI) and/or aristolochic acid II (AAII). The results obtained from recently collected PFS revealed that both AAI and AAII were detected in three out of 18 analysed PFS at levels up to 594.8 and 235.3 µg g(-1), respectively, being in line with the levels reported in literature. The EDIs resulting from intake of these PFS resulted in MOEs that were generally below 10,000, corroborating the priority for risk management. Although these results refer to PFS collected by targeted sampling strategies, the data reveal that AA-containing PFS are still freely available. When considering that the use of these samples may be limited to shorter periods of time, the EDIs might be lower, but MOE values would still be lower than 10,000 for more than 50% of the AA-containing PFS and herbal products. In conclusion, the presence of AAs in PFS and herbal products even several years after instalment of the legal restrictions still raises concern, especially for people who frequently use the respective PFS and herbal products.
Among the many roles played by small and medium enterprises (SMEs) in the food industry is the production of heritage foods such as peanut sauce. Unfortunately, the safety of peanut sauce is not always assured as the processing line is not controlled. Peanut sauce is usually made of peanuts and chilli, and these commodities are normally contaminated with Aspergillus spp. and aflatoxins (AFs). Hence, the objective of this study was to evaluate the practices related to reduction of AF hazard and the effect of interventions in peanut sauce processing. Peanut samples were collected from each step of peanut sauce processing from a small peanut sauce company according to four designs: (1) control; (2) oil-less frying of chilli powder; (3) addition of retort processing; and (4) combination of oil-less frying of chilli powder and retort processing. Oil-less frying of chilli powder (Design 2) reduced total AFs by 33-41%, retort processing (Design 3) reduced total AFs by 49%, while combination of these two thermal processes (Design 4) significantly reduced total AFs, by 57%. The present work demonstrated that Design 4 yielded the highest reduction of total AFs and is therefore recommended to be employed by SME companies.
Adulteration of herbal health supplements with phosphodiesterase-5 (PDE-5) inhibitors and their analogues is becoming a worldwide problem. The aim of this study was to investigate herbal and food products sold in the Malaysian market for the presence of these adulterants. Sixty-two products that claim to enhance men's sexual health were sampled between April 2014 and April 2016. These products included unregistered products seized by the Pharmacy Enforcement Division of the Ministry of Health (n = 39), products sent to the National Pharmaceutical Regulatory Agency for pre-registration testing (n = 9) and products investigated under the post-registration market surveillance programme (n = 14). The products were tested against an in-house spectral library consisting of 61 PDE-5 inhibitors and analogues using a validated liquid chromatography-mass spectrometry ion-trap-time-of-flight (LC-MS IT-TOF) method. Thirty-two (82%) of the unregistered products and two (14%) of the registered products were found to be adulterated with at least one PDE-5 inhibitor or analogue, while none of the pre-registration products contained adulterants. A total of 16 different adulterants were detected and 36% of the adulterated products contained a mixture of two or more adulterants. This study has demonstrated that the adulteration of unregistered herbal products in the Malaysian market is an alarming issue that needs to be urgently addressed by the relevant authorities.
The peanut supply chain in Malaysia is dominated by three main stakeholders (importers, manufacturers, retailers). The present study aimed to determine the levels and critical points of aflatoxin and fungal contamination in peanuts along the supply chain. Specifically, two types of raw peanuts and six types of peanut-based products were collected (N = 178). Samples were analysed for aflatoxins by using high-performance liquid chromatography. Results revealed that the aflatoxin contamination was significantly higher (P ≤ 0.05) in raw peanuts and peanut-based products from the retailers. However, there was no significant difference (P ≥ 0.05) in fungal contamination for both types of peanuts except for the total fungal count in raw peanuts from the retailers. Furthermore, raw peanut kernels from the retailers were the most contaminated ones ranged from
The objective of the study was to determine the effect of different types of soy sauce and marinating time on the formation of heterocyclic amines (HCAs) in roasted chicken. Chicken breast samples were marinated with sweet, salty, light and dark soy sauce at 0, 3, 6 and 12 h (control treatment was the chicken without marinade). The concentrations of free amino acids, sugars and creatinine were determined before roasting while HCA concentrations were determined after roasting. All types of soy sauce significantly increased (p ≤ 0.05) the concentration of HCAs in roasted chicken with increasing marinating time. The highest increment of total concentration of HCAs was found in samples marinated with light soy sauce (887%) followed by dark (375%), salty (193%) and sweet (169%) at 12 h. PhIP (2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine) showed a substantial reduction in samples only momentarily marinated with sweet, salty and dark soy sauce (0 h). Free amino acids were found to be more strongly correlated with the formation of HCAs than reducing sugars or creatinine.
High-quality DNA extracts are imperative for downstream applications in molecular identification. Most processed food products undergo heat treatments causing DNA degradation, which hampers application of DNA-based techniques for food authentication. Moreover, the presence of inhibitors in processed food products is also problematic, as inhibitors can impede the process of obtaining high qualities and quantities of DNA. Various approaches in DNA extraction and factors in structure and texture of various food matrices affecting DNA extraction are explained in this review.
A sensitive and selective gas chromatography with mass spectrometry method was developed for the simultaneous determination of three organophosphorus pesticides, namely, chlorpyrifos, malathion, and diazinon in three different food commodities (milk, apples, and drinking water) employing solid-phase extraction for sample pretreatment. Pesticide extraction from different sample matrices was carried out on Chromabond C18 cartridges using 3.0 mL of methanol and 3.0 mL of a mixture of dichloromethane/acetonitrile (1:1 v/v) as the eluting solvent. Analysis was carried out by gas chromatography coupled with mass spectrometry using selected-ion monitoring mode. Good linear relationships were obtained in the range of 0.1-50 μg/L for chlorpyrifos, and 0.05-50 μg/L for both malathion and diazinon pesticides. Good repeatability and recoveries were obtained in the range of 78.54-86.73% for three pesticides under the optimized experimental conditions. The limit of detection ranged from 0.02 to 0.03 μg/L, and the limit of quantification ranged from 0.05 to 0.1 μg/L for all three pesticides. Finally, the developed method was successfully applied for the determination of three targeted pesticides in milk, apples, and drinking water samples each in triplicate. No pesticide was found in apple and milk samples, but chlorpyrifos was found in one drinking water sample below the quantification level.
Food forgery has posed considerable risk to public health, religious rituals, personal budget and wildlife. Pig, dog, cat, rat and monkey meat are restricted in most religions, but their sporadic adulteration are rampant. Market controllers need a low-cost but reliable technique to track and trace suspected species in the food chain. Considering the need, here we documented a lab-on-a-chip-based multiplex polymerase chain reaction (PCR) assay for the authentication of five non-halal meat species in foods. Using species-specific primers, 172, 163, 141, 129 and 108-bp sites of mitochondrial ND5, ATPase 6 and cytochrome b genes were amplified to detect cat, dog, pig, monkey and rat species under complex matrices. Species-specificity was authenticated against 20 different species with the potential to be used in food. The targets were stable under extreme sterilisation (121°C at 45 psi for 2.5 h) which severely degrades DNA. The assay was optimised under the backgrounds of various commercial meat products and validated for the analysis of meatballs, burgers and frankfurters, which are popular fast food items across the globe. The assay was tested to detect 0.1% suspected meats under commercial backgrounds of marketed foods. Instead of simplex PCR which detects only one species at a time, such a multiplex platform can reduce cost by at least fivefolds by detecting five different species in a single assay platform.
This paper describes a short-amplicon-based TaqMan probe quantitative real-time PCR (qPCR) assay for the quantitative detection of canine meat in chicken nuggets, which are very popular across the world, including Malaysia. The assay targeted a 100-bp fragment of canine cytb gene using a canine-specific primer and TaqMan probe. Specificity against 10 different animals and plants species demonstrated threshold cycles (Ct) of 16.13 ± 0.12 to 16.25 ± 0.23 for canine DNA and negative results for the others in a 40-cycle reaction. The assay was tested for the quantification of up to 0.01% canine meat in deliberately spiked chicken nuggets with 99.7% PCR efficiency and 0.995 correlation coefficient. The analysis of the actual and qPCR predicted values showed a high recovery rate (from 87% ± 28% to 112% ± 19%) with a linear regression close to unity (R(2) = 0.999). Finally, samples of three halal-branded commercial chicken nuggets collected from different Malaysian outlets were screened for canine meat, but no contamination was demonstrated.
Fish tilapia Oreochromis mossambicus were collected from a contaminated Seri Serdang (SS) pond potentially receiving domestic effluents and an uncontaminated pond from Universiti Putra Malaysia (UPM). The fish were dissected into four parts namely gills, muscles, intestines, and liver. All the fish parts were pooled and analyzed for the concentrations of Cd, Cu, Fe, Ni, Pb, and Zn. Generally, the concentrations of all metals were low in the edible muscle in comparison to the other parts of the fish. It was found that the levels of all the heavy metals in the different parts of fish collected from the SS were significantly (P<0.05) higher than those from UPM, indicating greater metal bioavailabilities in the SS pond. The sediment data also showed a similar pattern with significantly (P<0.05) higher metal concentrations in SS than in UPM, indicating higher metal contamination in SS. Potential health risk assessments based on provisional tolerable weekly intake (PTWI) and the amount of fish required to reach the PTWI values, estimated daily intake (EDI), and target hazard quotient (THQ) indicated that health risks associated with heavy metal exposure via consumption of the fish's muscles were insignificant to human. Therefore, the consumption of the edible muscles of tilapia from both ponds should pose no toxicological risk of heavy metals since their levels are also below the recommended safety guidelines. While it is advisable to discard the livers, gills, and intestines of the two tilapia fish populations before consumption, there were no potential human health risks of heavy metals to the consumers on the fish muscle part.
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.