Use of pulsed light to increase the safety of ready-to-eat cured meat products

Pulsed light (PL) was tested for its efficacy to reduce Listeria monocytogenes and Salmonella enterica serovar Typhimurium on the surface of two ready-to-eat (RTE) dry cured meat products (salchichón and loin). Maximum log reductions between 1.5 and 1.8 cfu/cm² were obtained for both microorganisms when a fluence of 11.9 J/cm² was applied. Slight and particular differences in the instrumental color parameters were observed due to the treatment in both products, although no changes in the sensory analysis were detected either immediately after treatment or during 30 days storage in salchichón. Panelists perceived some changes in the sensory quality of loin immediately after treatment, but these differences disappeared along storage. PL could be considered a useful alternative to other non-thermal techniques for increasing the safety of RTE dry cured meat products.     

Strategies to assure the absence of GMO in food products application process in a confectionery firm

This article describes the strategies and the instruments applied in the development and implementation of a system aimed at assuring the production of food which is neither made of nor derived from genetically modified raw material in a confectionery firm. It was chosen to develop a specific planning method partially taken from HACCP and FMEA techniques, mainly as far as the systematic and rigorous analysis of risks is concerned (in this case, the contamination of raw material and/or their genetically modified derivatives along the food chain). The result is a management system model that food organizations can use to assure the traceability of all ingredients incorporated into their food products and, in the same time, to guarantee that these ingredients do not contain or consist or derive from genetically modified organisms (GMOs).     

Identification of meat and poultry species in food products using DNA barcoding

DNA barcoding is a promising method for the sequencing-based identification of meat and poultry species in food products. However, DNA degradation during processing may limit recovery of the full-length DNA barcode from these foods. The objective of this study was to investigate the ability of DNA barcoding to identify species in meat and poultry products and to compare the results of full-length barcoding (658 bp) and mini-barcoding (127 bp). Sixty meat and poultry products were collected for this study, including deli meats, ground meats, dried meats, and canned meats. Each sample underwent full and mini-barcoding of the cytochrome c oxidase subunit I (COI) gene. The resulting sequences were queried against the Barcode of Life Database (BOLD) and GenBank for species identification. Overall, full-barcoding showed a higher sequencing success rate (68.3%) as compared to mini-barcoding (38.3%). Mini-barcoding out-performed full barcoding for the identification of canned products (23.8% vs. 19.0% success), as well as for turkey and duck products; however, the primer set performed poorly when tested against chicken, beef, and bison/buffalo. Overall, full barcoding was found to be a robust method for the detection of species in meat and poultry products, with the exception of canned products. Mini-barcoding shows high potential to be used for species identification in processed products; however, an improved primer set is needed for this application.     

Occurrence of volatile and non-volatile N-nitrosamines in processed meat products and the role of heat treatment

Most of the available data on the occurrence of N-nitrosamines (NA) in processed meat products have been generated in the 1980s and 1990s and especially data on the occurrence of non-volatile NA (NVNA) are scarce. Therefore we have studied the levels of volatile nitrosamines (VNA) and NVNA in processed meat products on the Danish market (N = 70) and for comparison also products on the Belgian market (N = 20). The effect of heat treatment on the NA levels, in selected samples, was also studied, in order to enable an evaluation of how preparation before consumption affects the levels of NA. For the Danish products the mean levels of the VNA were generally low (≤0.8  μg kg⁻¹), whereas the mean levels of the NVNA were considerably higher (≤118 μg kg⁻¹). Slightly higher mean levels were indicated for the Belgian products (i.e. VNA ≤1.5  μg kg⁻¹ and NVNA ≤270 μg kg⁻¹). The sums of VNA were higher than 10 μg kg⁻¹ for one Danish sample and two Belgian samples. Levels of up to 2000 and 4000 μg kg⁻¹ of N-nitroso-thiazolidine-4-carboxylic acid (NTCA) an NVNA occurred in the Danish and the Belgian samples, respectively. The majority of the Danish processed meat products contain NVNA but also VNA occur. The levels of NA are comparable with those reported in previous and recent studies; however the frequency in which they are found may be lower and thereby also the mean contents. The levels of N-nitrosopiperidine (NPIP) increased by frying and baking, whereas varying impacts were observed for N-nitrosoproline (NPRO), N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), N-nitrosodiethylamine (NDEA) and N-nitrosomethylaniline (NMA) depending on the type of product and/or the heat treatment. The levels of the NVNA, NTCA and N-nitroso-2-methyl-thiazolidine 4-carboxylic acid (NMTCA) decreased after frying and baking.     

Improvements in the ecological safety of thermal process plants on conversion to a water-carbon fuel

The feasibility of a new type of fuel — water-carbon suspension (WCC) produced on the basis of hydrodynamic-cavitation effects — is examined. It is demonstrated that the rate of the combustion reaction of WCC is higher than that during the burning of coal dust. __________ Translated from Khimicheskoe i Neftegazovoe Mashinostroenie, No. 7, pp. 11–12, July, 2006.     

N型催化剂在间歇式聚丙烯装置上应用时聚丙烯产品等规度的控制

论述了使用N型催化剂生产聚丙烯时等规度的控制方法及影响因素,并与CS-1型催化剂进行了比较,结果显示N型催化剂生产聚丙烯等规度范围宽,易于调节,能满足多种品种和牌号,适用于中高档聚丙烯的生产使用。     

Identification of species in ground meat products sold on the U.S. commercial market using DNA-based methods

The objective of this study was to test a variety of ground meat products sold on the U.S. commercial market for the presence of potential mislabeling. Forty-eight ground meat samples were purchased from online and retail sources, including both supermarkets and specialty meat retailers. DNA was extracted from each sample in duplicate and tested using DNA barcoding of the cytochrome c oxidase I (COI) gene. The resulting sequences were identified at the species level using the Barcode of Life Database (BOLD). Any samples that failed DNA barcoding went through repeat extraction and sequencing, and due to the possibility of a species mixture, they were tested with real-time polymerase chain reaction (PCR) targeting beef, chicken, lamb, turkey, pork and horse. Of the 48 samples analyzed in this study, 38 were labeled correctly and 10 were found to be mislabeled. Nine of the mislabeled samples were found to contain additional meat species based on real-time PCR, and one sample was mislabeled in its entirety. Interestingly, meat samples ordered from online specialty meat distributors had a higher rate of being mislabeled (35%) compared to samples purchased from a local butcher (18%) and samples purchased at local supermarkets (5.8%). Horsemeat, which is illegal to sell on the U.S. commercial market, was detected in two of the samples acquired from online specialty meat distributors. Overall, the mislabeling detected in this study appears to be due to either intentional mixing of lower-cost meat species into higher cost products or unintentional mixing of meat species due to cross-contamination during processing.     

Development of an efficient real-time PCR assay to quantify enterotoxin-producing staphylococci in meat products

A SYBR Green-based real-time PCR (qPCR) procedure for the rapid and specific detection of enterotoxin-producing Staphylococcus spp. in meat products has been developed. For this, a specific primer pair based on conserved regions of enterotoxin genes was designed for detecting most of the described staphylococcal enterotoxins. No cross-reactivity with other microorganisms or non-enterotoxin-producing Staphylococcus spp. was detected. The detection limits of the assay were about 2–40 cfu/g for artificially contaminated meat products after 8 h enrichment period at 30 °C. Total time for assay completion was approximately 12 h. Thus, the qPCR method offers a useful, rapid and efficient tool for screening enterotoxin-producing Staphylococci in meat products. This tool could be also used for monitoring these foodborne pathogens in food safety preventive programs.     

A COIBar-RFLP strategy for the rapid detection of Engraulis encrasicolus in processed anchovy products

The species identity on anchovy products was tested through COI mitochondrial DNA sequences analysis in 50 samples belonging to 20 different commercial lots, such as anchovy fillets in vegetal oil, canned anchovies and anchovy paste. Seven samples (14%) were found to be not from Engraulis encrasicolus meats, confirming concerns of species substitution. Conventional COI-DNA barcoding revealed the presence of four different species, E. encrasicolus, Engraulis japonicus, Sardinella aurita and Sardina pilchardus, in the processed products labeled as European anchovy. The DNA barcoding was then used in combination with PCR-RFLP method to investigate labeling accuracy in processed anchovy products and to unveil putative fish fraud involving the replacement of the European anchovy, E. encrasicolus, with less valuable Engraulidae and Clupeidae species. We applied a COIBar-RFLP (Cytochrome Oxidase I Barcode-Restriction Fragment Length Polymorphism) analysis that yielded differential patterns allowing the unambiguous discrimination of European anchovy from the other species tested. The proposed molecular strategy relies on the efficiency of COI as a DNA barcode and proved very efficient and less expensive than DNA sequencing strategies. This approach may be useful in routine controls, especially in cases of large-scale sample screening.     

Application of ozone sprays as a strategy to improve the microbial safety and quality of salmon fillets

Ozone research investigating the efficacy of spray application mechanisms for balancing microbial safety with chemical quality attributes of high lipid content fish is lacking. The objectives of this study were to investigate the influence of aqueous spray treatments of 1 mg/L and 1.5 mg/L ozone on the microbial and chemical quality indices of Atlantic salmon fillets inoculated with Listeria innocua as a surrogate species replacing the pathogen Listeria monocytogenes. In order to simulate industry processing parameters, number of passes under spray nozzles (1, 2, and 3) was also investigated.Listeria counts resulting from treatment with three passes of 1 mg/L ozone sprays were significantly lower (p ≤ 0.05) than non-ozonated controls on days 0, 3, 6, and 10 of refrigerated storage at 4 °C. At both ozone concentrations, Listeria counts were significantly influenced (p ≤ 0.05) by the number of passes under spray nozzles with increasing passes resulting in increasing reductions. The residual antimicrobial effectiveness of ozone at both concentrations against aerobic bacterial populations on treated samples was limited to <6 days storage at 4 °C. Lipid oxidation analyses indicate that ozone concentration did not significantly affect (p ≤ 0.05) TBARS but did influence headspace propanal with 1 mg/L ozone treatments yielding approximately 30% higher propanal values than spray treatments of 1.5 mg/L ozone. Both TBARS and propanal levels were significantly influenced (p ≤ 0.05) by storage time, yet the number of spray passes did not significantly affect either measure of lipid oxidation. Our results indicate that ozone sprays at concentrations up to 1.5 mg/L are effective in reducing initial counts of aerobic bacterial populations and in significantly reducing (p ≤ 0.05) counts of L. innocua without causing significant increases in lipid oxidation levels in farmed Atlantic salmon fillets during refrigerated storage at 4 °C.     

海上稠油热采井防砂筛管热应力分析

为了研究稠油热采井防砂筛管的热稳定性,建立了筛管热应力分析模型,对不同工况下不同钢级的筛管基管进行研究。建模时为获得较高的网格密度,且在划分网格时不引起网格畸变,只取筛管基管的一部分进行模拟,忽略多元热流体化学因素的影响,采用8节点线性减缩积分应力单元C3D8R。结果认为,筛管弹性模量、膨胀系数与屈服强度受温度影响变化显著,对筛管热应力分析有明显的影响;热应力补偿器的配备可显著缓解防砂管柱热应力,提高其热稳定性。     

A high incidence of species substitution and mislabelling detected in meat products sold in South Africa

Due to their high market value, meat products are often targets for species substitution and adulteration. DNA-based methods are recognized as the most appropriate means to detect such fraudulent practices, however, these have not been extensively employed for the authentication of meat products available in South Africa. The aim of this study was to utilize a variety of molecular techniques to evaluate the extent of meat product mislabelling prevailing on the local market. A total of 139 processed meat products (minced meats, burger patties, deli meats, sausages and dried meats) were collected from retail outlets and butcheries in South Africa. The enzyme-linked immunosorbent assay (ELISA) was employed for the detection of undeclared plant proteins (soya and gluten) in the samples. A commercial DNA-based LCD array was used to screen the samples for the presence of 14 animal species, the results of which were confirmed by species-specific polymerase chain reaction (PCR) and in some cases also DNA sequencing. The results revealed that 95 of 139 (68%) samples contained species which were not declared on the product labelling, with the incidence being highest in sausages, burger patties and deli meats. Soya and gluten were identified as undeclared plant proteins in a large number of samples (>28%), while pork (37%) and chicken (23%) were the most commonly detected animal species. Unconventional species such as donkey, goat and water buffalo were also discovered in a number of products. Overall, this study confirmed that the mislabelling of processed meats is commonplace in South Africa and not only violates food labelling regulations, but also poses economic, religious, ethical and health impacts.     

池火环境下液化石油气储罐响应规律及影响因素

有关液化石油气(LPG)储罐火灾爆炸的研究,国内外研究者对池火环境下LPG储罐的热响应规律开展了大量的实验研究和数值模拟工作,但研究结果尚难以给出通用规律。为此,利用FLUENT软件建立了池火灾环境下LPG储罐热响应模型,以英国HSE管理局现场实验的卧式LPG储罐为例进行了三维数值模拟,计算结果与实验实测结果吻合较好。数值模拟结果表明:①池火环境下储罐内介质温度分布总体上呈现上部高下部低的趋势,气相及液相区的温度分层明显;②储罐内介质压力上升速率随着充装率的增大而增大;③LPG储罐失效是由介质温度升高导致的储罐内介质压力升高和气相区壁温升高导致的材料强度下降共同引起的。     

A multiplex real-time PCR method for the quantitative determination of equine (horse) fractions in meat products

The recent horse meat scandal that rocked Europe in early 2013 shows how important it is for the routine food control authorities to constantly evolve analytical tools for the accurate evaluation of meat products among others, to ensure that product declaration and actual composition correlate. While in most cases qualitative detection approaches suffice for product evaluation, in other cases a quantitative analysis is important to distinguish between inadvertent contamination and deliberate adulteration.In this work an optimized real-time qPCR-based approach is presented and compared with another real-time based method for the detection of equine sequences among others in meat products. The method is a multiplex system for the simultaneous quantification of horse, beef, pork and sheep fractions, and was validated for use in the routine analysis of meat products. We describe a modular multiplex approach, where a quadruplex system (without sheep) and a pentaplex assay (with an integrated sheep detection system) can be applied in meat detection and quantification strategies. The analysis is matrix independent and relies on concomitant quantification of the animal species present in the food sample against the backdrop of myostatin, a universal sequence present in most mammalian and poultry species. The limit of detection of the analytical method was 10 genome copy equivalents. For validation of the method, meat samples comprising differing meat compositions were analysed, and the assay performed well in terms of robustness and reproducibility.     

HACCP-based approach to the derivation of an on-farm food safety program for the Australian red meat industry

The standard Codex HACCP approach was modified to allow a hazard analysis to be conducted at an industry level which could then be used to derive appropriate on-farm food safety control measures for cattle, sheep and goat production in Australia. Scientific information from a through chain risk profile of the red meat industry was used as a major resource for the hazard analysis. The process resulted in the identification of critical control points for control of bovine spongioform encephalopathy (BSE), prevention of violations of maximum residue limits with agricultural and veterinary chemicals and infection with Cysticercus bovis (Beef Measles). By applying this HACCP-based approach it was determined that the application of a simple set of good agricultural practices (GAP) on-farm would be effective in ensuring low risk. It was, therefore, concluded that on-farm food safety schemes may not warrant full HACCP plans at the individual enterprise level as long as appropriate GAP is in place. The results provide red meat producers with the elements of a HACCP-based food safety scheme that is scientifically justifiable, understandable and realistic to apply which are essential elements that underpin successful implementation and compliance by industry. Subsequently, an on-farm food safety program has been developed to provide an appropriate level of protection for consumers as well as to protect Australia’s trade from food safety-related issues.     

Natural occurrence of aflatoxin B1, ochratoxin A and citrinin in Croatian fermented meat products

When domestic animals are exposed to mycotoxins, significant amounts of the latter shall be carried over into animal products such as milk, eggs and meat. This study was carried out in order to determine the possible presence of aflatoxin B₁ (AFB₁), ochratoxin A (OTA) and citrinin (CIT) in game sausages (n = 15), semi-dry sausages (n = 25) and fermented dry-meat products (n = 50), randomly taken from individual producers and the Croatian market. AFB₁ and OTA were quantified using ELISA, while CIT was quantified using HPLC-fluorescence detector. Out of 90 samples, the fungi most frequently isolated from dry-cured meat products were of Penicillium species, while Aspergillus was isolated from only one sample. As much as 68.88% of the samples were positive for mycotoxins. Finally, the analysis of different types of meat products resulted in OTA identification in 64.44%, CIT identification in 4.44% and AFB₁ identification in 10% of the samples. The maximum OTA concentrations established in the commercial sausage samples equalled to 7.83 μg/kg, while that of AFB₁ amounted to 3.0 μg/kg. Generally, although OTA was detected in all three types of products in different percentage shares, mutual differences were not statistically significant (P > 0.05).     

Conversion of a delayed coking unit to mild thermal cracking (visbreaking) conditions

The possibility of converting a combined delayed-coking unit to operating in conditions of mild thermal cracking (visbreaking) of petroleum resids is examined. Major technical and process solutions that ensure the maximally efficient use of the existing equipment are proposed. The possibility of obtaining boiler fuel with a maximum residual hydrogen sulfide content of 2 ppm is demonstrated. Cost effectiveness is ensured by a significant increase in the volume of refined petroleum resids.