Conjugated linoleic acid in meat and meat products: A review

Conjugated linoleic acid (CLA) consists of a group of geometric and positional isomers of linoleic acid to which anticancerogenic, antidiabetic, and antiatherogenic effects, as well as effects on immune system, bone metabolism, and body composition are attributed. CLA is found predominantly in milk and meat of ruminants due to the importance of rumen micro-organism in the formation of CLA and its precursors. This review attempts to give an overview of the available data on intramuscular CLA concentrations in meat and meat products originating from different animal species. The factors influencing these concentrations are discussed and the estimated human daily intakes as well as the percentage provided by meat are reported.     

Application of near infrared reflectance spectroscopy to predict meat and meat products quality: A review

Over the past three decades, near infrared reflectance (NIR) spectroscopy has been proved to be one of the most efficient and advanced tools for the estimation of quality attributes in meat and meat products. This review focuses on the use of NIR spectroscopy to predict different meat properties, considering the literature published mainly in the last decade. Firstly, the potential of NIR to predict chemical composition (crude protein, intramuscular fat, moisture/dry matter, ash, gross energy, myoglobin and collagen), technological parameters (pH value; L*, a*, b* colour values; water holding capacity; Warner–Bratzler and slice shear force) and sensory attributes (colour, shape, marbling, odour, flavour, juiciness, tenderness or firmness) are reviewed. Secondly, the usefulness of NIR for classification into meat quality grades is presented and thirdly its potential application in the industry is shown. The review indicates that NIR showed high potential to predict chemical meat properties and to categorize meat into quality classes. In contrast, NIR showed limited ability for estimating technological and sensory attributes, which may be mainly due to the heterogeneity of the meat samples and their preparation, the low precision of the reference methods and the subjectivity of assessors in taste panels. Hence, future work to standardize sample preparation and increase the accuracy of reference methods is recommended to improve NIR ability to predict those technological and sensory characteristics. In conclusion, the review shows that NIR has a considerable potential to predict simultaneously numerous meat quality criteria.     

Biologically active polyamines in beef, pork and meat products: A review

Dietary polyamines (PAs) putrescine (PUT), spermidine (SPD) and spermine (SPM) participate in an array of roles in human metabolism. Nevertheless, under some physiological conditions they can be undesirable. Meat and meat products are among important sources of PAs in human nutrition, mainly of SPM. The usual contents of PUT, SPD and SPM in fresh beef and pork are <2, <5 and 20-40mgkg(-1), respectively. Current information on changes of PAs during meat storage corresponds with PUT formation by bacterial activity mainly of pseudomonads and Enterobacteriaceae. However, data on SPD and SPM changes during meat chill-storage have been inconsistent. Culinary processing of meat probably does not change SPD and SPM levels. PUT can be formed in different meat products in relation to the microbial population of the raw materials used and the hygienic level of manufacturing process. SPD and SPM contents seem to remain stable during processing of non-fermented meat products or decrease during dry-cured ham ripening. PUT contents increase commonly to 60-140mgkg(-1) in dry spontaneously fermented sausages, however, contents up to several hundreds mgkg(-1) are not extraordinary. Starter cultures are usually able to decrease PUT formation considerably. SPD and SPM contents in dry fermented sausages are comparable with levels typical for fresh meat. Data on SPD and SPM changes during ripening and storage are inconsistent. A decrease of the both polyamines during a storage period has been usually reported.     

A strategy for molecular species detection in meat and meat products by PCR-RFLP and DNA sequencing using mitochondrial and chromosomal genetic sequences

Molecular species detection in food has become common in the last 10 years. The methods are sensitive enough to detect small, but relevant, amounts of one species in composed food. We have developed a strategy for detecting different animal species in food by molecular means. This strategy uses a combination of published PCR systems and new developed PCR primer systems for the detection of porcine, bovine, ovine, avian, cervine and equine DNA by PCR followed by restriction analysis (PCR-RFLP). In some cases, analysis is completed by DNA sequencing. The species detection system includes an amplification control and so is in accordance with the relevant food standards.     

A DNA method for qualitative identification of plant raw materials in feedstuff

This research developed a simple and not expensive DNA method for the qualitative identification of plant raw materials used as feed mixtures. Specific simple sequence tagged (STS) markers were developed to detect faba bean (Lectin A gene), field pea (Convicilin A gene), grain sorghum (UDP-glucosyltransferase gene) and barley (Hordoindoline-a gene), whereas identification of durum and common wheat (lipid transfer protein gene), soybean (Gly m Bd 30K allergen gene) and maize (invertase gene) was carried out using markers available from the literature. Cross-reactivity of the primer pairs was also checked against oat, rye, kidney bean and lentil. The method was effectively applied to the analysis of flour mixtures and extruded feedstuff. It could be included in traceability and certification of animal feeding systems within high quality animal production chains which are strictly related to the production area by the valorisation of locally grown raw materials.     

肉食品中的胆固醇氧化物

胆固醇是肌肉组织的一种组分。新鲜肉中不存在胆固醇氧化物。内在长期贮存和加热中生成胆固醇氧化物。肉食品中的胆固醇氧化物对人的健康有害。肉中胆固醇氧化物的总量与肉的脂类氧化物存在着线性相关。在饲料中添加生育酚以提高内源性生育酚，其动物的肉制品中胆固醇氧化物明显减少。     

Authentication of meat and meat products

In recent years, interest in meat authenticity has increased. Many consumers are concerned about the meat they eat and accurate labelling is important to inform consumer choice. Authentication methods can be categorised into the areas where fraud is most likely to occur: meat origin, meat substitution, meat processing treatment and non-meat ingredient addition. Within each area the possibilities for fraud can be subcategorised as follows: meat origin—sex, meat cuts, breed, feed intake, slaughter age, wild versus farmed meat, organic versus conventional meat, and geographic origin; meat substitution—meat species, fat, and protein; meat processing treatment—irradiation, fresh versus thawed meat and meat preparation; non-meat ingredient addition—additives and water. Analytical methods used in authentication are as diverse as the authentication problems, and include a diverse range of equipment and techniques. This review is intended to provide an overview of the possible analytical methods available for meat and meat products authentication. In areas where no authentication methods have been published, possible strategies are suggested.     

Meat traceability using DNA markers: application to the beef industry

Consumer concerns about beef demands instruments to assure its traceability. A methodology using DNA markers is proposed for beef identification focussing on a Spanish beef certification, Ternera de Navarra (Beef of Navarra). To validate this methodology the number of markers used and the implications of population structure in individual identification were evaluated. In order to get practical implementation, the sampling levels required, depending on the number of markers and amount of possible fraud, is also discussed. Using at least eight very informative markers the origin of retailed meat is always found independent of genetic population structure. The total control of fraud would be very expensive using large-scale application of DNA analyses and a strategy based on anonymous sampling is proposed.     

Chitosan and mint mixture: A new preservative for meat and meat products

Meat is prone to both microbial and oxidative spoilage and therefore it is desirable to use a preservative with both antioxidant and antimicrobial properties. Mint extract alone had good antioxidant activity but poor antimicrobial activity, while chitosan alone showed poor antioxidant activity with excellent antimicrobial properties. Therefore, the potential of chitosan and mint mixture (CM), as a preservative for meat and meat products, was investigated. Addition of chitosan to mint extract did not interfere with the antioxidant activity of mint. In the case of 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, the IC₅₀ value for CM (17.8 μg/ml) was significantly (p ? 0.05) lower than that for mint extract (23.6 μg/ml). CM efficiently scavenged superoxide and hydroxyl radicals. The antimicrobial activities of CM and chitosan were comparable against the common food spoilage and pathogenic bacteria, the minimum inhibitory concentration being 0.05%. CM was more effective against Gram-positive bacteria. The shelf life of pork cocktail salami, as determined by total bacterial count and oxidative rancidity, was enhanced in CM-treated samples stored at 0–3 °C.     

Survey of authenticity of meat species in food products subjected to different technological processes,by means of PCR-RFLP analysis

Polymerase chain reaction (PCR) coupled to restriction-fragment length polymorphism analysis (RFLP) was considered for exploring the incidence of incorrect labelling in food products containing one or more meat species. Universal primers CYT b1/CYT b2, which amplify a variable region of the mitochondrial cytochrome b of vertebrates, and endonucleases PalI, MboI, HinfI and AluI were used for this purpose. Fifty food products, nine of them raw or cured and the other 41 subjected to a variety of technological processes such as pre-cooking and freezing, cooking and smoking, dehydration or sterilisation, were investigated. Twenty of the 50 products declared mixtures of meat species on their labels. Fifteen (30%) of the 50 food samples investigated displayed an incorrect qualitative labelling. While this affected only one (11.1%) of the nine raw/cured products, 14 (34.2%) of the 41 products subjected to some type of heat-processing were not correctly labelled. The undeclared presence of turkey was the most frequent concern, since it was detected in seven food products. The complete absence of a declared species of high commercial value—such as beef or roe-deer—was observed in another four cases. The PCR-RFLP method used here proved to be a rapid and easy-to-perform two-step analytical approach to achieve qualitative meat species identification in raw and cooked food products containing one or more different species.     

A fast and accurate method for controlling the correct labeling of products containing buffalo meat using High Resolution Melting (HRM) analysis

The substitution of high priced meat with low cost ones and the fraudulent labeling of meat products make the identification and traceability of meat species and their processed products in the food chain important. A polymerase chain reaction followed by a High Resolution Melting (HRM) analysis was developed for species specific detection of buffalo; it was applied in six commercial meat products. A pair of specific 12S and universal 18S rRNA primers were employed and yielded DNA fragments of 220 bp and 77 bp, respectively. All tested products were found to contain buffalo meat and presented melting curves with at least two visible inflection points derived from the amplicons of the 12S specific and 18S universal primers. The presence of buffalo meat in meat products and the adulteration of buffalo products with unknown species were established down to a level of 0.1%. HRM was proven to be a fast and accurate technique for authentication testing of meat products.     

铜在畜产品中的安全性评价

为了保证畜产品的安全性,通过动物实验研究了高铜的危害性,根据对某市铜超标情况的调查,运用风险评估软件@RISK4.5建立畜产品中铜的风险评估模型,最终给出日允许摄入量ADI值,以对畜产品中铜超标的风险进行全面评估。为促进畜产品安全,保护消费者健康及有关部门进行食品安全的风险管理提供依据。     

Consumer perceptions of traceability: A cross-national comparison of the associated benefits

Consumer perceptions regarding traceability were investigated by means-end-chain laddering. Consumers in four European countries were questioned about the benefits they associate with traceability related attributes. The benefits consumers associate with traceability are in terms of health, quality, safety and control, of which the latter was associated with trust and confidence. These benefits were similarly important in the countries investigated. Cross-national differences were also observed. Importantly, both quality and safety were shown to be related to traceability in the consumers′ minds with quality implying safety. The results show that traceability may contribute to improving consumer confidence. The most important aspects of traceability which should be incorporated into communication with consumers are discussed.     

Meat quality of "Galician Mountain" foals breed. Effect of sex, slaughter age and livestock production system

The effects of sex, slaughter age (9 vs. 12 months) and livestock production system (freedom extensive system (FES) vs. semi extensive system (SES)) of "Galician Mountain" foals breed on meat quality from the Longissimus dorsi (LD) muscle were investigated. Forty-two foals had been used for this study, 19 (11 females and 8 males) were reared in a semi extensive system and weaned three months prior to slaughtering (8 and 11 were slaughtered at 9 and 12 months, respectively) while the other 23 (11 females and 12 males) were reared together with its mothers in a system in freedom and were slaughtered at the age of 9 months. The obtained results showed that there were no significant differences between the sexes and the slaughter age whereas the livestock production system was a significant variation source on intramuscular fat content and meat tenderness because SES foals showed 51.6% more of IMF and the improved meat tenderness achieved a shear force of <3 kg. In general, the meat from foals of the study at hand showed very lean meat (<0.3% in IMF) with a high protein content (>20.5%) and heme-iron (1.62 mg/100g meat) comparable to veal meat. Furthermore, the meat samples showed a higher luminosity (L*>40), a very good water holding capacity, measured by cooking losses (<18.3%), and a tenderness less than 4 kg. Thus, it can be classified as "very tender" meat.     

Irradiation effects on meat flavor: A review

Irradiating fresh meat, even at low doses, can result in off-odors and flavors which have been described as rotten egg, bloody, fishy, barbecued corn, burnt, sulfur, metallic, alcohol or acetic acid. The odors vary with the type of meat, temperature during irradiation, oxygen exposure during and/or after the irradiation process, packaging and presence of antioxidative substances. Irradiation can induce formation of isooctane-soluble carbonyl compounds in the lipid fraction and low molecular weight, acid-soluble carbonyls in the protein fraction of meat. Increasing irradiation dose increases these compounds however, cooking reduces them. Among the volatile components, 1-heptene and 1-nonene are influenced most by irradiation dose, and aldehydes (propanal, pentanal, hexanal) are influenced most by packaging type (aerobic vs vacuum). Sulfur-containing volatiles formed from sulfur-containing compounds (primarily amino acids) also contribute to irradiation odor. Dimethyltrisulfide is one of the most potent off-odor compounds, contributing fishy, putrid odors, followed by bismethylthiomethane (sulfurous). Reducing the temperature during the irradiation process reduces the effects on odor/flavor because free radical generation and dispersion are reduced. Ultimately, radiolysis of water into free radical species (OH,H, H(3)0(+), e(aq)(-)) may be the initiators of both lipid oxidation breakdown products and sulfur-containing volatiles responsible for irradiation odor. Methods to decrease the detrimental effects of irradiation include oxygen exclusion (vacuum packaging), replacement with inert gases (nitrogen), addition of protective agents (antioxidants), and post-irradiation storage to allow flavor to return to near-normal levels (re-packaging or double packaging in oxygen permeable film).     

Strategies for designing novel functional meat products

In recent years, much attention has been paid to physiological functions of foods due to increasing concerns for health. Although there has been limited information of physiological functions of meat until recently, several attractive meat-based bioactive compounds, such as carnosine, anserine, l-carnitine, conjugated linoleic acid, have been studied. Emphasizing these activities is one possible approach for improving the health image of meat and developing functional meat products. This article provides potential benefits of representative meat-based bioactive compounds on human health and an overview of meat-based functional products. Strategies for designing novel functional meat products utilizing bioactive peptides and/or probiotic bacteria, is also discussed. This article focuses particularly on the possibility of meat protein-derived bioactive peptides, such as antihypertensive peptides. There are still some hurdles in developing and marketing novel functional meat products since such products are unconventional and consumers in many countries recognize meat and meat products to be bad for health. Along with accumulation of scientific data, there is an urgent need to inform consumers of the exact functional value of meat and meat products including novel functional foods.     

Past, current and potential utilisation of active and intelligent packaging systems for meat and muscle-based products: A review

Interest in the use of active and intelligent packaging systems for meat and meat products has increased in recent years. Active packaging refers to the incorporation of additives into packaging systems with the aim of maintaining or extending meat product quality and shelf-life. Active packaging systems discussed include oxygen scavengers, carbon dioxide scavengers and emitters, moisture control agents and anti-microbial packaging technologies. Intelligent packaging systems are those that monitor the condition of packaged foods to give information regarding the quality of the packaged food during transport and storage. The potential of sensor technologies, indicators (including integrity, freshness and time-temperature (TTI) indicators) and radio frequency identification (RFID) are evaluated for potential use in meat and meat products. Recognition of the benefits of active and intelligent packaging technologies by the food industry, development of economically viable packaging systems and increased consumer acceptance is necessary for commercial realisation of these packaging technologies.     

Chemical safety of meat and meat products

Since the Second World War the consumer behaviour in developed countries changed drastically. Primarily there existed the demand for sufficient food after a period of starvation, afterwards the desire for higher quality was arising, whereas today most people ask for safe and healthy food with high quality. Therefore a united approach comprising consistent standards, sound science and robust controls is required to ensure consumers' health and to maintain consumers' confidence and satisfaction. Chemical analysis along the whole food chain downstream (tracking) from primary production to the consumer and upstream (tracing) from the consumer to primary production is an important prerequisite to ensure food safety and quality. In this frame the focus of the following paper is the “chemical safety of meat and meat products” taking into account inorganic as well as organic residues and contaminants, the use of nitrite in meat products, the incidence of veterinary drugs, as well as a Failure Mode and Effect Analysis (FMEA) system assessing (prioritizing) vulnerable food chain steps to decrease or eliminate vulnerability.     

Production variations of nutritional composition of commercial meat products

Changes in nutrient composition that habitually occur in commercial meat products in the course of production need to be considered for purposes of production systems control, consumer safety, nutritional information, labelling, official regulations or quality of food composition databases. This paper reports a study of production time variations in the nutritional composition of commercial meat products with different characteristics such as composition (protein and fat levels) and processing conditions (lean-only cuts, ground meat, fresh, cooked, brined, etc.). Proximate composition, fatty acid profile, cholesterol concentration, energy value and mineral content were evaluated. Over the year variability in nutrient composition were generally observed in meat products. The variability of composition (proximate analysis and fatty acid proportion) was greater in lean-only cut products as compared with ground meats. The relationship between fat and cholesterol contents of meat products presented correlation coefficients of 0.809 (P < 0.001) and 0.859 (P < 0.001) for the relationship between cholesterol and the sum of fat and protein contents. Several of the products considered are significant sources of Fe, Zn and K. Production variations in nutritional profiles observed in various meat products can affect the dietary assessment of some components, and also the product's nutritional labelling.