Scientific Opinion on the public health risks related to mechanically separated meat (MSM) derived from poultry and swine

Prevalence of Salmonella species and factors associated with contamination of mechanically recovered poultry meat imported into South Africa, 2016-2017

Background and Aim

Mechanically recovered meat (MRM) products have been linked to outbreaks of human salmonellosis. However, no studies have investigated the prevalence of Salmonella species in MRM products in South Africa despite the products being imported. Therefore, this study aimed to estimate the prevalence and factors associated with Salmonella spp. contamination of mechanically recovered poultry meat (MRPM) imported into South Africa.

Materials and Methods

This study used secondary data of MRPM consignments imported through a port entry into South Africa from May 2016 to December 2017. Crude and factor-specific proportions of Salmonella positive MRPM and their 95% confidence intervals were calculated. A logistic regression model was used to assess the association among country, season, importer, year, and MRPM Salmonella status.

Results

A total of 8127 MRPM consignments were imported. Seventeen percentages (17.18%, 985/5733) of consignments tested positive for Salmonella species and only 364 isolates were serotyped. Salmonella Heidelberg (73.90%, 269/364) was the most common serotype followed by Salmonella Infantis (6.59%, 24/364), Salmonella Salamae (4.67%, 17/364), and Salmonella Schwarzengrund (3.57%, 13/364). The odds of a consignment testing positive for Salmonella spp. was higher among consignments from country-B (Odds Ratio [OR]: 3.958, p < 0.0001) compared to "All others." The odds of testing positive for Salmonella were also higher among consignments imported in autumn (OR: 1.488, p < 0.0001) but lower among those imported in spring (OR: 0.767, p = 0.0004) and summer (OR: 0.843, p < 0.0001) when compared to the winter season. Consignments imported in 2016 compared to 2017 were 1.563 times (p < 0.0001) as likely to test positive for a Salmonella species.

Conclusion

Salmonella species were reported in MRPM consignments in this study with Salmonella Heidelberg being the most common serotype. Furthermore, some Salmonella serotypes reported in this study have been implicated in foodborne disease outbreaks. Country of origin, season, and year of importation were significantly associated with the odds of a consignment testing positive for Salmonella species.

Determination of Calcium in Meat Products by Automatic Titration with 1,2-Diaminocyclohexane-N,N,N',N'-tetraacetic Acid

Mechanically separated meat (MSM) is a by-product of the poultry industry that requires routine quality assessment. Calcium content is an indirect indicator of bone debris in MSM but is difficult to determine by EDTA titration due to the poor solubility of calcium phosphate. Therefore, 1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid was used instead, which has two orders of magnitude higher affinity for calcium ions. In addition, the auxiliary complexing agents triethanolamine and Arsenazo III, an indicator that is sensitive to low calcium concentrations, were used. Automatic titration endpoint detection was performed using an immersion probe at 660 nm. It has been shown that the color change in Arsenazo III can also be read with an RGB camera. The CDTA titration procedure has been tested on commercial Bologna-type sausages and the results were in line with AAS and ICP reference data. The content of calcium in sausages turned out to be very diverse and weakly correlated with the content of MSM. The tested MSM samples had a wide range of calcium content: from 62 to 2833 ppm. Calcium-rich poultry by-products include fat and skin (115 to 412 ppm), articular cartilage (1069 to 1704 ppm), and tendons (532 to 34,539 ppm). The CDTA titration procedure is fully suitable for small meat processing plants due to its simplicity of use and low cost.

Application of Density Measurements for Discrimination and Evaluation of Chemical Composition of Different Types of Mechanically Separated Meat (MSM)

At present, the problem of identifying and controlling different types of Mechanically Separated Meat (MSM) is a very important practical issue in the meat industry. To address this challenge, the authors propose a new, analytical method for the discrimination and characterization of MSM that uses density measurements. The method proposed by the authors, in contrast to the analytical methods existing so far, is rapid, non-destructive, relatively simple and can be computerized. The density measurements of meat samples were conducted with a modified pycnometric method. Statistically significant (p<0.01) differences were found in the evaluated mean values of density for all investigated types of meat. Subsequently, the density measurements were correlated with the physicochemical properties of meat samples. A high correlation coefficient was found between the density of meat samples and the content of protein, sodium and fat. The authors have proven that density measurements allow for rapid discrimination of various types of MSM, and can also be effectively used to determine the chemical composition of MSM samples, e.g., the content of protein, fat and sodium.

Feasibility of In-Line Raman Spectroscopy for Quality Assessment in Food Industry: How Fast Can We Go?

Raman spectroscopy is a viable tool within process analytical technologies due to recent technological advances. In this article, we evaluate the feasibility of Raman spectroscopy for in-line applications in the food industry by estimating the concentration of the fatty acids EPA + DHA in ground salmon samples (n = 63) and residual bone concentration in samples of mechanically recovered ground chicken (n = 66). The samples were measured under industry like conditions: They moved on a conveyor belt through a dark cabinet where they were scanned with a wide area illumination standoff Raman probe. Such a setup should be able to handle relevant industrial conveyor belt speeds, and it was studied how different speeds (i.e., exposure times) influenced the signal-to-noise ratio (SNR) of the Raman spectra as well as the corresponding model performance. For all samples we applied speeds that resulted in 1 s, 2 s, 4 s, and 10 s exposure times. Samples were scanned in both heterogenous and homogenous state. The slowest speed (10 s exposure) yielded prediction errors (RMSECV) of 0.41%EPA + DHA and 0.59% ash for the salmon and chicken data sets, respectively. The more in-line relevant exposure time of 1 s resulted in increased RMSECV values, 0.84% EPA + DHA and 0.84% ash, respectively. The increase in prediction error correlated closely with the decrease in SNR. Further improvements of model performance were possible through different noise reduction strategies. Model performance for homogenous and heterogenous samples was similar, suggesting that the presented Raman scanning approach has the potential to work well also on intact heterogenous foods. The estimation errors obtained at these high speeds are likely acceptable for industrial use, but successful strategies to increase SNR will be key for widespread in-line use in the food industry.

Critical Analysis of Pork QMRA Focusing on Slaughterhouses: Lessons from the Past and Future Trends

Foodborne microbial diseases have a significant impact on public health, leading to millions of human illnesses each year worldwide. Pork is one of the most consumed meat in Europe but may also be a major source of pathogens introduced all along the farm-to-fork chain. Several quantitative microbial risk assessment (QMRA) have been developed to assess human health risks associated with pork consumption and to evaluate the efficiency of different risk reduction strategies. The present critical analysis aims to review pork QMRA. An exhaustive search was conducted following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) methodology. It resulted in identification of a collection of 2489 papers including 42 on QMRA, after screening. Among them, a total of 29 studies focused on Salmonella spp. with clear concern on impacts at the slaughterhouse, modeling the spreading of contaminations and growth at critical stages along with potential reductions. Along with strict compliance with good hygiene practices, several potential risk mitigation pathways were highlighted for each slaughterhouse step. The slaughterhouse has a key role to play to ensure food safety of pork-based products but consideration of the whole farm-to-fork chain is necessary to enable better control of bacteria. This review provides an analysis of pork meat QMRA, to facilitate their reuse, and identify gaps to guide future research activities.

Effect of Chicken Bone Extracts on Metabolic and Mitochondrial Functions of K562 Cell Line

Background: Tetracyclines’ use in intensive animal farming has raised some concerns regarding the biosafety for humans. Increasing evidences have revealed the presence of these drugs in processed animal by-products, such as bone, throughout the food chain. A potential off-target of tetracyclines is the bacterial-like mitochondrial translational machinery, thereby causing proteostatic alterations in mitochondrial DNA-encoded components of the oxidative phosphorylation system. Methods: The Seahorse methodology, confocal microscopy imaging of mitochondrial potential and reactive oxygen species, and q-RT-PCR analysis of the expression of genes involved in mitochondrial biogenesis and mitophagy were carried out on human lymphoblast derived K562 cell line challenged with bone powder derived from chicken treated with or without oxytetracycline and pure oxytetracycline. Results: A complex dose-dependent profile was attained with a low dosage of bone powder extracts causing a metabolic adaptation hallmarked by stimulation of the mitochondrial respiration and enhanced expression of mitochondriogenic factors in particular in cells challenged with oxytetracycline-free bone extract. Conversely, a higher dosage of bone powder extracts, regardless of their source, caused a progressive inhibition of mitochondrial respiration and glycolysis, ultimately leading to cell death. No significant effects of the pure oxytetracycline were observed. Conclusion: Bone powder, regardless of chicken treatment, contains and releases factors/chemicals responsible for the observed effects on energy metabolism. Quantitative differential effects appear to depend on biochemical alterations in the bone matrix caused by antibiotics rather than antibiotics themselves.

The use of bioactive properties of sage preparations to improve the storage stability of low-pressure mechanically separated meat from chickens2

The aim of this study was to determine the effect of Salvia officinalis L. (sage) preparations on the storage stability of vacuum-packed low-pressure mechanically separated meat (MSM) from chickens stored at -18°C for 9 mo. Chilled low-pressure MSM coming from 4 production batches was obtained from the plant located in north-eastern Poland. All sage preparations-a water extract, ethanol extracts, and an essential oil-were prepared and added to the MSM under laboratory conditions. Five samples of low-pressure MSM were prepared that differed in terms of the type of sage preparation added: control-without addition of sage, WE-2.0% addition of water extract from sage, E40-2.0% addition of 40% (vol/vol) ethanol extract from sage, E70-2.0% addition of 70% (vol/vol) ethanol extract from sage, and EOS-0.1% addition of essential oil from sage. The MSM samples were assessed immediately after arrival into the laboratory and after 1, 2, 3, 4, 6, and 9 mo of storage. The quality changes of MSM samples were determined on the basis of the thiobarbituric acid reactive substances (TBARS) index and microbial analyses. On the basis of the TBARS index it was proved that addition of essential oil and (40% and 70% (vol/vol)) as well as water extracts of sage significantly (P < 0.05) slowed down fat oxidation processes in low-pressure MSM from chickens. The growth of mesophilic aerobic bacteria and psychrotrophic bacteria, coliforms, and Enterobacteriaceae was significantly (P < 0.05) restricted by all sage preparations tested. The most effective inhibitory effect for groups of bacteria analyzed in this study was demonstrated by sage essential oil, despite insignificant (P > 0.05) differences between the preparations. In conclusion, it was found that sage preparations are rich in bioactive compounds. Due to their antioxidant and antibacterial properties, especially sage oil and ethanol extracts may be recommended as an auxiliary factor to prolong the storage stability of frozen, vacuum-packed low-pressure MSM from chickens.

Evaluation of antioxidant and antimicrobial activity of oregano (Origanum vulgare L.) preparations during storage of low-pressure mechanically separated meat (BAADER meat) from chickens

The goal of this study was to determine the effect of Origanum vulgare L. (oregano) preparations on the storage stability of vacuum-packed low-pressure mechanically separated meat (BAADER meat) from chickens stored at - 18 °C for 9 months. Oregano was added into the meat as a dried spice, extracts in water and ethanol (40 and 70% (v/v)), and an essential oil. The control samples did not contain oregano. The samples were examined immediately after arrival into the laboratory and after 1, 2, 3, 4, 6, and 9 months of storage. Oregano essential oil was most effective in slowing down lipid oxidation and inhibiting the growth of bacteria in BAADER meat. The number of coliform bacteria in the BAADER meat samples with the 0.1% essential oil was significantly lower than that in the control samples. The storage time was seen to have a more significant effect on the quality of BAADER meat.