The Effects of X-Ray Irradiation on Safety and Nutritional Value of Food: A Systematic Review Article.

X-ray is a non-thermal technology that has shown good efficacy in reducing pathogenic and spoilage bacteria, viruses and parasites. X-ray hygiene technology resulted in a high microbial loss in numerous food products, such as dairy products, ready-to-eat shrimp, oysters, fresh products, strawberries, shredded iceberg lettuce, and spinach leaves. Some X-ray studies on food safety have shown that X-ray is an effective technology and is also an appropriate alternative to the electron beam and gamma rays, and can be used in the food industry without side effects on human health. Besides, we reviewed the X-ray effect on the nutritional value of food. Therefore in this study, we aimed to review the available pros and cons of current studies regarding X-rays' effects on the food industry.

Screening of intact yeasts and cell extracts to reduce Scrapie prions during biotransformation of food waste.

Yeasts can be used to convert organic food wastes to protein-rich animal feed in order to recapture nutrients. However, the reuse of animal-derived waste poses a risk for the transmission of infectious prions that can cause neurodegeneration and fatality in humans and animals. The aim of this study was to investigate the ability of yeasts to reduce prion activity during the biotransformation of waste substrates-thereby becoming a biosafety hurdle in such a circular food system. During pre-screening, 30 yeast isolates were spiked with Classical Scrapie prions and incubated for 72 h in casein substrate, as a waste substitute. Based on reduced Scrapie seeding activity, waste biotransformation and protease activities, intact cells and cell extracts of 10 yeasts were further tested. Prion analysis showed that five yeast species reduced Scrapie seeding activity by approximately 1 log10 or 90%. Cryptococcus laurentii showed the most potential to reduce prion activity since both intact and extracted cells reduced Scrapie by 1 log10 and achieved the highest protease activity. These results show that select forms of yeast can act as a prion hurdle during the biotransformation of waste. However, the limited ability of yeasts to reduce prion activity warrants caution as a sole barrier to transmission as higher log reductions are needed before using waste-cultured yeast in circular food systems.

Validation studies of the latex agglutination test for the detection of Trichinella larvae in meat products.

Human trichinellosis is a foodborne disease caused by ingestion of meat infected with Trichinella muscle larvae. To control Trichinella spp. infection in the European Union, all slaughtered pigs from holdings that are not officially recognized as applying controlled housing conditions and other animals susceptible to Trichinella infection and intended for human consumption should be examined by one of the approved digestion methods described in Regulation (EU) No. 2015/1375. In the past, Trichinella outbreaks due to the consumption of cured wild boar or pork products have been described in several European countries, making the identification of the larvae from these products relevant for Trichinella control. Therefore, this study aimed to validate the newly approved latex agglutination test (Trichin-L) for routine testing of cured meat products. The test was validated based on the OIE Guidelines using pork products spiked with Trichinella larvae. The sensitivity of the method varied greatly depending on the investigated meat product and was usually lower than for the gold standard, the magnetic stirrer method. The detection rate reached 80% for three larvae and 60% for one larva in cured pork sausages. A detection rate of 100% for three larvae and 50% for one larva was found in bacon. For frozen samples (-20°C) the Trichin-L kit is similarly sensitive as for cured samples. Further, to determine the performance of the test under field conditions, pork products from regions with known high Trichinella prevalences confiscated by customs authorities at two German international airports were analyzed. Problems associated with the Trichin-L test were incomplete digestion due to fatty ingredients, spices and very dry meat products, resulting in data which could not be evaluated. Therefore, the test is currently not suitable for the detection of Trichinella larvae in cured meat products and needs further adaptation steps to increase both usability and sensitivity.

Proficiency testing to detect Trichinella larvae in meat in the European Union.

According to the Commission Implementing Regulation (EU) 2015/1375 (replacing the Commission Regulation (EC) No 2075/2005), all animals, which are potential carriers of Trichinella spp. larvae, should be tested at the slaughterhouse or game-handling establishments according to one of the approved tests. One of the core duties of the European Union Reference Laboratory for Parasites is to organize proficiency testing (PT), as stated in the Commission Regulation (EC) No. 882/2004 of the European Parliament and of the Council. The aim of this work was to evaluate the results of PTs of the digestion method carried out by the National Reference Laboratories for Parasites (NRLPs) over a nine year period (2007-2015). Participating laboratories received a panel of samples consisting in 35g or 100g of minced pork or horse meat spiked with Trichinella spiralis live larvae. The number of spiked samples varied from 2 to 9 over the years. A negative control was also included in the panel, except during the 2015 PT, when only positive samples were used. The percentage of NRLPs, which passed the PT, increased from 83.3% in 2007 to 100% in 2014. Considering the number of recovered larvae, the heterogeneity in participant's results reduced overtime. The values of the overall mean difference between spiked and recovered larvae decreased during the study period, witnessing a general improvement of NRLPs performance and confirming the effectiveness of PT for a good performance of this test.

Quality Control of Trichinella Testing at the Slaughterhouse Laboratory: Evaluation of the Use of a 400-Micrometer-Mesh-Size Sieve in the Magnetic Stirrer Method.

The performance of a 400-µm-mesh-size sieve (sieve400) has not previously been compared with that of a 180-µm-mesh-size sieve (sieve180). Using pork samples spiked with 0 to 10 Trichinella muscle larvae and an artificial digestion method, sieve performance was evaluated for control of Trichinella in meat-producing animals. The use of a sieve400 resulted in 12% lower larval counts, 147% more debris, and 28% longer counting times compared with the use of a sieve180. Although no false-negative results were obtained, prolonged counting times with the sieve400 may have an impact on performance in a high-throughput environment such as a slaughterhouse laboratory. Based on our results, the sieve180 remains the sieve of choice for Trichinella control in meat in slaughterhouse laboratories, according to the European Union reference method (European Commission regulation 2075/2005). Furthermore, the results of the present study contribute to the discussion of harmonization of meat inspection requirements among countries.

Impacts of globalisation on foodborne parasites.

Globalisation is a manmade phenomenon encompassing the spread and movement of everything, animate and inanimate, material and intangible, around the planet. The intentions of globalisation may be worthy--but may also have unintended consequences. Pathogens may also be spread, enabling their establishment in new niches and exposing new human and animal populations to infection. The plethora of foodborne parasites that could be distributed by globalisation has only recently been acknowledged and will provide challenges for clinicians, veterinarians, diagnosticians, and everyone concerned with food safety. Globalisation may also provide the resources to overcome some of these challenges. It will facilitate sharing of methods and approaches, and establishment of systems and databases that enable control of parasites entering the global food chain.

Bovine cysticercosis--development of a real-time PCR to enhance classification of suspect cysts identified at meat inspection.

Laboratory confirmation methods are important in bovine cysticerosis diagnosis as other pathologies can result in morphologically similar lesions resulting in false identifications. We developed a probe-based real-time PCR assay to identify Taenia saginata in suspect cysts encountered at meat inspection and compared its use with the traditional method of identification, histology, as well as a published nested PCR. The assay simultaneously detects T. saginata DNA and a bovine internal control using the cytochrome c oxidase subunit 1 gene of each species and shows specificity against parasites causing lesions morphologically similar to those of T. saginata. The assay was sufficiently sensitive to detect 1 fg (Ct 35.09 ± 0.95) of target DNA using serially-diluted plasmid DNA in reactions spiked with bovine DNA as well as in all viable and caseated positive control cysts. A loss in PCR sensitivity was observed with increasing cyst degeneration as seen in other molecular methods. In comparison to histology, the assay offered greater sensitivity and accuracy with 10/19 (53%) T. saginata positives detected by real-time PCR and none by histology. When the results were compared with the reference PCR, the assay was less sensitive but offered advantages of faster turnaround times and reduced contamination risk. Estimates of the assay's repeatability and reproducibility showed the assay is highly reliable with reliability coefficients greater than 0.94.

PCR test for detecting Taenia solium cysticercosis in pig carcasses.

Polymerase chain reaction (PCR) test was employed to detect Taenia solium DNA in muscle lesions for validation of the meat inspection results of slaughtered pigs. Two sets of oligonucleotide primers, one targeted against the large subunit rRNA gene (TBR primers) and the other targeted against cytochrome c oxidase subunit 1 gene (Cox1 primers) of T. solium were used in this study. On reactivity in PCR test, the TBR primers and the Cox1 primers yielded products of 286 and 984 bp, respectively, in cysticercosis positive cases. Both the sets of primers were found to be highly specific, since they did not yield any PCR product in negative controls. A total of 225 pig carcasses were screened for cysticercosis by meat inspection, out of which 25 carcasses with visible cysts (16 viable and 9 degenerated cysts) were also confirmed to be positive for cysticercosis in PCR test. However, out of the 35 carcasses with suspected lesions on meat inspection, only two were found to be positive for cysticercosis in PCR test. The detection limits for both the primer sets were analyzed. The TBR primer set could detect up to 10 pg of cysticercus DNA, whereas the Cox1 primer set could detect only up to 1 ng. It is evident from the study that PCR test is an efficient tool for validation of meat inspection results and also to rule out ambiguity in carcass judgment of suspected cases of porcine cysticercosis.

Investigation on penetration of three conventional foodstuffs packaging polymers with two different thicknesses by larvae and adults of major species of stored-product pest insects.

Despite modern methods of packaging, stored agricultural products are still under attack by stored-insect pests. Therefore, determination of the best polymer and appropriate thickness inhibiting the penetration of the insects must be considered. In this study, we investigated the ability of penetration and the rates of contamination by nine important stored product pest insects for three conventional flexible polymers (polyethylene, cellophane and polypropylene) at two thicknesses (16.5 and 29 microm), which are used as pouches for packing of agricultural products. We used adults of T. castaneum (Coleoptera), S. granarius (Coleoptera), R. dominica (Coleoptera), C. maculates (Coleoptera), O. surinamensis (Coleoptera), and larvae of P. interpunctella (Lepidoptera), E. kuehniella (Lepidoptera), S. cerealella (Lepidoptera) and T. granarium (Coleoptera). Results showed that for most of the species penetration occurred between 4 days and 2 weeks, but there were significant differences (p < or = 0.05) in the penetration of three polymers (cellophane, polyethylene and polypropylene) by the insects. Among the polymers, polyethylene with a thickness of 16.5 microm showed the highest degree of penetration and was the most unsuitable polymer for packaging of foodstuffs. Application of this polymer led to a complete infestation of the product and a lot of punctures were created by the insects. In contrast, no penetration was observed in polypropylene polymer with a thickness of 29 microm. Furthermore, adults and larvae of all species showed a much lower penetration when there was no food present in the pouches and this was the case for all polymers tested.

Evaluation of the risk of transmission of Trichinella in pork production systems in Argentina.

Recently, there has been interest in programs that certify pork production practices that minimize the risk of exposure of pigs to Trichinella spiralis. Certification might be useful for reducing the risk of human trichinellosis from pork in Argentina, but more information is needed on pig production practices and sources of Trichinella infection in Argentinian pigs. In this study, 21 pig farms were assessed for Trichinella infection including some farms using total and partial confinement management, and others with pigs raised exclusively outdoors. A total of 3224 muscle samples were collected from pigs raised on these farms and tested to determine the presence of T. spiralis larvae by artificial digestion. Serum samples from the same 3224 pigs were tested for antibodies to T. spiralis by ELISA. For each farm, a questionnaire was completed summarizing information about management factors and this information was used to assess risk factors for exposure of T. spiralis. Based on the results, pigs raised outdoors were more likely to be infected than pigs raised in total or partial confinement (p< or =0.05). Pigs fed waste products containing meat were 12.5 times more likely to be infected than pigs not fed waste containing meat (p<0.01). The role played by rats in transmission of Trichinella is unclear; however, on farms with evidence of wild animals and access of pigs to wildlife carcasses, the prevalence of Trichinella infection was significantly higher. All pigs raised under good hygienic and sanitary conditions were negative for Trichinella infection by both artificial digestion and ELISA.

Trichinella diagnostics and control: mandatory and best practices for ensuring food safety.

Because of its role in human disease, there are increasing global requirements for reliable diagnostic and control methods for Trichinella in food animals to ensure meat safety and to facilitate trade. Consequently, there is a need for standardization of methods, programs, and best practices used in the control of Trichinella and trichinellosis. This review article describes the biology and epidemiology of Trichinella, and describes recommended test methods as well as modified and optimized procedures that are used in meat inspection programs. The use of ELISA for monitoring animals for infection in various porcine and equine pre- and post-slaughter programs, including farm or herd certification programs is also discussed. A brief review of the effectiveness of meat processing methods, such as freezing, cooking and preserving is provided. The importance of proper quality assurance and its application in all aspects of a Trichinella diagnostic system is emphasized. It includes the use of international quality standards, test validation and standardization, critical control points, laboratory accreditation, certification of analysts and proficiency testing. Also described, are the roles and locations of international and regional reference laboratories for trichinellosis where expert advice and support on research and diagnostics are available.

Complete validation of a unique digestion assay to detect Trichinella larvae in horse meat demonstrates the reliability of this assay for meeting food safety and trade requirements.

A tissue digestion assay using a double separatory funnel procedure for the detection of Trichinella larvae in horse meat was validated for application in food safety programs and trade. The assay consisted of a pepsin-HCl digestion step to release larvae from muscle tissue and two sequential sedimentation steps in separatory funnels to recover and concentrate larvae for detection with a stereomicroscope. With defined critical control points, the assay was conducted within a quality assurance system compliant with International Organization for Standardization-International Electrotechnical Commission (ISO/IEC) 17025 guidelines. Samples used in the validation were obtained from horses experimentally infected with Trichinella spiralis to obtain a range of muscle larvae densities. One-, 5-, and 10-g samples of infected tissue were combined with 99, 95, and 90 g, respectively, of known negative horse tissue to create a 100-g sample for testing. Samples of 5 and 10 g were more likely to be positive than were 1-g samples when larval densities were less than three larvae per gram (lpg). This difference is important because ingested meat with 1 lpg is considered the threshold for clinical disease in humans. Using a 5-g sample size, all samples containing 1.3 to 2 lpg were detected, and 60 to 100% of samples with infected horse meat containing 0.1 to 0.7 lpg were detected. In this study, the double separatory funnel digestion assay was efficient and reliable for its intended use in food safety and trade. This procedure is the only digestion assay for Trichinella in horse meat that has been validated as consistent and effective at critical levels of sensitivity.

Control of neurocysticercosis by routine medical and veterinary services.

Taenia solium neurocysticercosis and ocular cysticercosis are two of the most devastating parasitic infections, which need to be controlled for medical and economic reasons. This paper discusses why control measures are not implemented adequately in endemic areas and proposes simple operational interventions, based on focus-oriented chemotherapy of T. solium taeniasis using existing health care infrastructure and improved collaboration between medical and veterinary services. These interventions can be quickly and easily implemented (irrespective of other applicable control measures), with medical and veterinary staff being adequately trained, and safe, effective and cheap taenicides made available.

[Epidemiology of human trichinellosis in Poland--currently and in the past]. / Epidemiologia wlosnicy w polsce dawniej i dzis.

Since the XIX century human trichinellosis has remained an unsolved problem of public healthcare in Poland. This paper describes the past situation and analyses current changes in the epidemiological pattern of trichinellosis in Poland. Epidemiological data from the last 60 years, point out that the number of human cases as well as the number of deaths caused by trichinellosis has decreased significantly. Up to 90s the main source of Trichinella infection for people was pork. Among other implemented control measures, the introduction of the artificial digestion method in the early 80s to detect trichinellosis in pigs resulted in a shift in the sources of Trichinella infection in humans - pork was replaced with wild boar meat. In the years 1990-1995 the number of outbreaks due to pork consumption was 3.5-times higher than in the years 2000-2005. In the early nineties pork was the source of infection causing about 71% of all outbreaks; in 2000-2005 that number has fallen to only 12%. On the other hand wild boar meat was responsible for 23% of the outbreaks in 1990-1995 and as many as 88% of all outbreaks in the years 2000-2005. Moreover the number of persons infected in the outbreaks significantly decreased. The study of wild animals demonstrated that wild boars in Poland are infected not only with T. spiralis but also with Trichinella britovi. These results and EU recommendations indicate a requirement of determining the Trichinella species which cause infections in outbreaks. In the 3 trichinellosis outbreaks in 2005 the infected meat products were examined with molecular tools. T. spiralis species larvae were the etiological agents of infection in all these outbreaks. The current epidemiological situation of trichinellosis in Poland indicates a need of increasing the awareness of risks related to wild boar meat consumption among the general public. Introducing the artificial digestion method as an obligatory method for wild boar meat examination is also necessary.

The need for implementation of International Commission on Trichinellosis recommendations, quality assurance standards, and proficiency sample programs in meat inspection for trichinellosis in Serbia.

Implementation of methods to control inspection for Trichinella in meat recommended by International Commission on Trichinellosis (ICT), particularly the introduction of the quality assurance standards and proficiency panels for certified analysts is extremely important in Serbia and other countries where Trichinellosis is endemic. In spite of existing regulations, including the inspection of 0.5 g samples of diaphragm by the compression method or by artificial digestion of 1g samples, in Serbia 280 people were diagnosed with clinical trichinellosis after consumption of inspected meat during the period 2001--2002. These outbreaks, which occurred in the municipalities of Kumane, Surcin and Bogatic, were a consequence of inadequate application of inspection methods and insufficient education of some veterinary inspectors. The problem of inadequate veterinary inspection in Serbia can be overcome by strict application of the ICT recommendations for the control of Trichinella with specific emphasis on implementing the quality assurance system (QAS) and proficiency sampling (PS/--PP/panel).

Trichinae certification in the United States pork industry.

Control of Trichinella infection in U.S. pork has traditionally been accomplished by inspection of individual carcasses at slaughter or by post-slaughter processing to inactivate parasites. We propose that an alternative to individual carcass testing or processing can be used when pigs are raised in production systems where risk of exposure to Trichinella spiralis has been mitigated. Declines in prevalence of this parasite in U.S. domestic swine during the last 30 years, coupled with improvements in pork production systems, now allow Trichinella control to be shifted to the farm through implementation of specific pork production practices. Knowledge of risk factors for exposure of swine to T. spiralis was used to develop an objective audit of risk that can be applied to pork production sites. In a pilot study, 461 production site audits were performed by trained veterinary practitioners. The on-farm audit included aspects of farm management, bio-security, feed and feed storage, rodent control programs and general hygiene. Of the 461 production site audits, 450 audits (97.6%) indicated compliance with the required good production practices. These sites are eligible for certification under the U.S. Trichinae Certification Program and will be audited regularly to maintain that status. The described trichinae certification mechanism will establish a process for ensuring the Trichinella safety of swine, and ultimately food products derived from swine, at the production level.

An internationally recognized quality assurance system for diagnostic parasitology in animal health and food safety, with example data on trichinellosis.

A quality assurance (QA) system was developed for diagnostic parasitology and implemented for several diagnostic assays including fecal flotation and sedimentation assays, trichomonad culture assay, and the testing of pork and horse meat for Trichinella to facilitate consistently reliable results. The system consisted of a validated test method, procedures to confirm laboratory capability, and protocols for documentation, reporting, and monitoring. Specific system components included a quality assurance manual, training program, proficiency panels, inter-laboratory check-sample exchange program, assay critical control points, controls, and audits. The quality assurance system of the diagnostic laboratory was audited according to ISO/IEC Standard 17025 by an international third party accrediting body and accredited as a testing laboratory for the specific parasitology tests. Test results generated from the laboratory were reliable and scientifically defensible according to the defined parameters of the tests and were therefore valid for a variety of purposes, including food safety, international trade, and declaration of disease status in an animal, herd, farm, or region. The system was applicable to various test methods for the detection of parasites in feces or other samples, and a digestion test system developed for Trichinella was used as an example. A modified tissue digestion assay was developed, validated, and implemented by the Canadian Food Inspection Agency's Centre for Animal Parasitology for efficiency and quality assurance. The details of the method were properly documented for routine testing and consisted of a homogenization process, an incubation at 45+/-2 degrees C, and two sequential sedimentations in separatory funnels to concentrate and clarify final aliquots for microscopic examination. To facilitate consistently reliable test results, 14 critical control points were identified and monitored, analysts were certified, and the test system verified through the use of validation data, proficiency samples, and training modules.

Proficiency samples for quality assurance in Trichinella digestion tests.

A reliable method to produce proficiency samples containing known numbers of Trichinella spiralis cysts for use in quality assurance systems for Trichinella digestion tests was developed and validated. A filtrate containing Trichinella cysts was produced by homogenizing and filtering the muscles of an experimentally infected rat. Using a stereomicroscope and micropipette, intact cysts were removed from the filtrate and were transferred onto an agar substrate to allow accurate counting and subsequent transfer into a sample matrix. The proficiency sample matrix consisted of 20-g balls of lean ground beef and was combined with 80 g of a Trichinella-free muscle tissue to obtain the required 100-g sample weight for the assay. The mean overall larval recovery from 404 proficiency samples was 93.0%. Larval recoveries > or = 95, 85, and 75% occurred in 52.4, 84.4, and 94.3%, respectively, of the 404 samples tested. Results indicated that, after a short training period, technicians with no prior experience in digestion techniques performed as well as experienced technicians. The maximum shelf life of proficiency samples was not determined but was at least 3 weeks. Validation data were used to develop panels composed of proficiency samples prepared as described above and to establish guidelines for the interpretation of proficiency panel results.