Official Food Control Research Articles

Antimicrobial resistance profiles of Listeria monocytogenes isolated from ready-to-eat products in Poland in 2007–2011

The aim of the study was to characterize strains of Listeria monocytogenes isolated from ready to eat (RTE) products collected as part of official food control and monitoring in Poland. A total of 105 L. monocytogenes isolates from RTE products: 54- cakes and 51 – delicatessen products were examined. The presence L. monocytogenes in cakes and delicatessen products was 0.4% and 0.7% respectively suggesting the level of contamination of RTE products with L. monocytogenes is very low.

Consistency in inspection processes of food control officials and efficacy of official controls in restaurants in Finland

We evaluated the consistency and efficacy of inspection processes of 17 Finnish municipal food control units by analyzing inspection reports of 83 restaurants over the 2007–2011 period and by interviewing food business operators. Fifty-six officials of the food control units responded to an electronic questionnaire about their inspection activities. We found several factors related to the food establishment, the food control official and the working unit of the official that can affect the inspection processes and the efficacy of the controls. The use of checklists and templates for inspection reports enhanced the consistency and efficacy of the controls. The templates also reduced the time used for, and increased the quality of, reporting. Time limits for correcting non-compliances had a significant effect on the efficacy of controls.

Risk characterization of antimicrobial resistance of Salmonella in meat products

Antimicrobial resistance is considered to be a major public health concern in the framework of Horizon 2020. The risk to human health from foodborne antimicrobial resistant microorganisms can be determined and assessed using risk analysis tools in accordance with Codex principles. Therefore, the objective of this work was to determine the qualitative risk characterization of the presence of Salmonella resistant strains in meat products. Consequently, a total of 2050 whole and minced samples of poultry, pork and beef, were assessed. Samples were obtained by the Official Food Control Services of the Valencian administration (Spain), in the province of Valencia between January 2006 and June 2012. Salmonella was not found in any samples of beef. Salmonella strains isolated in poultry and pork samples were not resistant to amikacin, amoxicillin, cephalothin ciprofloxacin levofloxacin and ofloxacin. However, Salmonella isolates found in poultry had a high level of resistance to nalidixic acid, while those found in pork were more resistant to tetracycline and ampicillin. Furthermore, 41% of Salmonella isolates were resistant to three or more antibiotics. Finally, considering these results as exposure and taking into account the severity of the potential adverse health effects related to the different antimicrobials, risk characterization was estimated. As a result, three cases were classified as “Very high additional risk” all of them in minced meat, two cases in poultry (gentamicin and nalidixic acid) and one in pork (ampicillin). In the rest of the cases of resistance, the risk was classified as “high additional risk”. This highlights the importance of continued surveillance and the need to take measures in the primary sector in order to minimize the risk for the consumer.

Prevalence and antimicrobial resistance of Listeria monocytogenes and Salmonella strains isolated in ready-to-eat foods in Eastern Spain

Antimicrobial resistance is a major global public health concern and a food safety issue considered in the framework of Horizon 2020. Bearing this in mind, the current study determined the prevalence of Listeria monocytogenes and Salmonella strains isolated in ready-to-eat food sampled in industry and retail between 2006 and 2012 by the Official Food Control Services of the Valencian administration (Spain). The presence of L. monocytogenes was analysed in a total of 2864 samples including pasteurized cheese (624); cooked ham (487); dried pork sausages (192); ice cream (758) and smoked salmon (803). The presence of Salmonella was analysed in a total of 1264 samples: pasteurized cheese (289); cooked ham (316); dried pork sausages (78); ice cream (376) and smoked salmon (205). The results showed that L. monocytogenes was present in 3.8% of the samples, being most common in smoked salmon. Salmonella was not found in any of the products studied with the exception of 7 out 78 samples of dried pork sausage. Both L. monocytogenes and Salmonella showed resistance to 4 antimicrobials (ampicillin, cephalothin, tetracycline and trimethoprim-sulfamethoxazole). Moreover, the former was resistant to amikacin, ciprofloxacin, erythromycin and vancomycin while the later showed resistance to amoxicillin-clavulanate and chloramphenicol. Furthermore, multi-resistance was found for both microorganisms.

Development of loop-mediated isothermal amplification (LAMP) assay for rapid and sensitive identification of ostrich meat.

Animal species identification is one of the primary duties of official food control. Since ostrich meat is difficult to be differentiated macroscopically from beef, therefore new analytical methods are needed. To enforce labeling regulations for the authentication of ostrich meat, it might be of importance to develop and evaluate a rapid and reliable assay. In the present study, a loop-mediated isothermal amplification (LAMP) assay based on the cytochrome b gene of the mitochondrial DNA of the species Struthio camelus was developed. The LAMP assay was used in combination with a real-time fluorometer. The developed system allowed the detection of 0.01% ostrich meat products. In parallel, a direct swab method without nucleic acid extraction using the HYPLEX LPTV buffer was also evaluated. This rapid processing method allowed detection of ostrich meat without major incubation steps. In summary, the LAMP assay had excellent sensitivity and specificity for detecting ostrich meat and could provide a sampling-to-result identification-time of 15 to 20 minutes.

Quality control of used deep‐frying oils

Quality of deep‐fried food is inseparably attached to the quality of the used deep‐frying oil. Taste, flavor, shelf life, consumer acceptance, and safety of fried food essentially depend on frying oil quality. Evaluation of frying oil quality therefore is an important issue for both frying operators and official food control agencies. Organoleptic evaluation is an essential step in the monitoring of frying fat quality. Several official laboratory methods are available to support the sensory evaluation. Total polar materials (TPM) and polymer TAGs (PTG) are the most reliable parameters for this purpose. Recommended and widely accepted limits are 24% for TPM and 12% for PTG. When oxidative alterations strongly predominate over thermal alterations, sensory defects can appear before TPM and PTG reach recommended values. In that case additional parameters like anisidine value, carbonyl value, or epoxy fatty acids should be considered. A number of physical and chemical rapid methods are available. Despite the limited informative value and the possibility of error of rapid tests, they are essential for fryer operators, because they deliver information about fat quality in real‐time. Most reliable for most applications are quick tests measuring TPM. A unique and powerful tool for the simultaneous detection of multiple parameters corresponding to thermal and oxidative alterations is near infrared spectroscopy (NIRS), which will become more and more important in future.

Temperature control efficacy of retail refrigeration equipment

Abstract Temperature control of food products in retail food stores (food stores) is essential for food safety. The food business operator (FBO) must ensure that the product temperatures comply with food regulations. This study investigated the temperatures of products in 32 food stores and the relationship between the product temperature with the temperature of the refrigeration equipment (open front) and the temperature settings. The FBOs awareness of the equipment and product temperatures and the equipment temperature settings (temperature setpoint, alarm setpoint, timing for alarm to go off) were also investigated. The food stores represented four nationwide chain-store groups in Finland. The study included four categories of food products namely: fresh fish, minced meat, vacuum packed ready-to-eat processed fish and other ready-to-eat products, all of which are easily perishable products. Vacuum packed fish products and other ready-to-eat products are also sensitive to Listeria monocytogenes contamination. The temperatures of the products (n = 84) and refrigeration equipment (n = 86) were measured by a temperature data logger by the health inspector for 24 h. Temperature violations were observed in 50% of the products and 17.9% of the products exceeded the temperature limit by over 3 °C for more than 30 min. Products that were most often in noncompliance were fresh fish and vacuum packed processed fish products. Temperature violations were observed in food stores in all four chain-store groups and no significant difference between the chain-store groups was observed. The temperature of the equipment as measured by the refrigeration equipment's fixed thermometers differed significantly from the temperatures of the products. Moreover, no significant correlation was found between the equipment temperatures (fixed thermometer) and the products with the exception of minced meat. These results highlight, that the product temperature could not be reliably determined by the equipment's fixed thermometer. There was a lack of awareness of temperature settings in all chain-store groups. Only three stores (9.4%) were aware of all the settings of the inspected equipment. The results show that the FBOs own-check of equipment and product temperatures is not functioning correctly in food stores. This can have serious consequences for food safety. FBOs, equipment manufacturers, monitoring system providers and official food control authorities should take active measures to improve the situation.

Restaurant business operators' knowledge of food hygiene and their attitudes toward official food control affect the hygiene in their restaurants

We surveyed the knowledge and attitudes of restaurant business operators (RBOs) with respect to their restaurants' hygiene. A total of 82 RBOs were interviewed and a hygiene evaluation was performed in each of the restaurants by one researcher. Fifty-six food control officials responded to an electronic questionnaire. Based on our results, positive correlations exist between hygiene knowledge of the RBOs, their attitudes toward food hygiene and official food control, and their restaurants' hygiene level. Proper justification of control measures used by food control officials and a negotiative approach appear to be highly important for improving restaurant hygiene.

Total and inorganic arsenic in foods of the first Hong Kong total diet study

Arsenic (As) is a metalloid that occurs in different inorganic and organic forms, which are found in the environment from both natural occurrence and anthropogenic activity. The inorganic forms of As (iAs) are more toxic as compared with the organic As, but so far most of the occurrence data in food collected in the framework of official food control are still reported as total As without differentiating the various As species. In this paper, total As and iAs contents of 600 total diet study (TDS) samples, subdivided into 15 different food groups, were quantified by high-resolution inductively coupled plasma mass spectrometry (HR-ICP/MS) and hydride generation (HG) ICP/MS respectively. The method detection limits for both total As and iAs were 3 μg As kg−1. As the samples were prepared for TDS, food items were purchased directly from the market or prepared as for normal consumption, i.e. table ready, in the manner most representative of and consistent with cultural habits in Hong Kong as far as practicable. The highest total As and iAs content were found in ‘fish, seafood and their products’ and ‘vegetables and their products’ respectively. Besides, this paper also presents the ratios of iAs and total As content in different ready-to-eat food items. The highest ratio of iAs to total As was found in ‘vegetables and their products’. It is likely that iAs in vegetables maintained its status even after cooking.

Recovery of Anisakid larvae by means of chloro-peptic digestion and proposal of the method for the official control

Anisakidae larvae belonging to the genera Anisakis and Pseudoterranova, are the most responsible for zoonosis transmitted by fish products (anisakidosis). Acquired by the consumption of raw or undercooked marine fish or squid, the anisakid larvae may cause pathogenic diseases like gastric or intestinal anisakiasis and gastro-allergic disorders. In accordance with current EU legislation, the fresh fish products must be inspected visually in order to detect the possible presence of visible parasites. It is recognized that the visual method is not accurate enough to detect the larvae of parasites in food preparations containing raw or practically raw seafood and it clearly emerges that the official system of control needs to be able to utilise an most efficient analytical technique. In this work, the authors have drawn up and validated an analytical method, which involves artificial digestion and the use of a heated magnetic stirrer, based on the EU Regulation n. 2075/2005. The larvae isolated are then subjected to morphological identification at genus level by using optical microscope. The method, proved to be suitable for the detection of live and dead larvae of anisakidae in ready-to-eat foodstuffs containing raw fish or cephalopods and it is fast and accurate. The method showed high levels of sensitivity and specificity, and the suitability of its use in official food control was confirmed. Its use should be incorporated systematically into specific monitoring programs for the control of foodstuffs containing raw fish products.

Validation studies for multicomponent quantitative NMR analysis: the example of apple fruit juice

Laboratories intending to work as official laboratories for food control have to be accredited according to ISO/IEC 17025. This necessitates the use of validated analytical methods. In this study, we present validation results of the recently commercialized “JuiceScreener” based on nuclear magnetic resonance (NMR) spectroscopy with apple juice as application example. The quantitative analysis included 29 compounds such as major sugars, amino acids, organic acids, as well as acetoin, arbutin, benzaldehyde, hydroxymethylfurfural, acetaldehyde, methanol, and ethanol. Limit of detection (LOD), limit of quantification (LOQ), coefficients of variation (CV) for replicated measurements, repeatability, linear range, and recoveries were determined. The LOD and LOQ values varied in the 0.48–16 mg/L and in the 1.9–122 mg/L ranges with the lowest values for shikimic acid and highest for the principal sugars. The 1H NMR assays were linear in broad concentration ranges (R > 0.99), encompassed typical concentration in apple juices, and are sufficient to control the requirements of the code of practice of the European fruit juice association. Recoveries between 92 and 109 % on average for five separate standard additions were obtained. The average CVs were found to be 3.0 % (intraday) and 3.6 % (interday) excluding sample preparation (by measuring five time one solution) and 5.5 % (intraday) and 6.2 % (interday) including sample preparation (by preparing and analyzing five separate samples). The NMR method was judged as suitable for the simultaneous quantification of compounds in apple juice for official food control purposes. Our results show that multiparameter NMR methods can be successfully validated with standard instrumentarium and that they are fit for the purpose of official food control.

Potential and limitations of non-targeted fingerprinting for authentication of food in official control

The investigation of the so-called food fingerprints provides high potential with regard to the characterization and identity verification of food. Therefore, this kind of non-targeted analysis obtained increasingly importance during the recent years. These applications are usually based on spectroscopic and spectrometric data providing the capability for a comprehensive characterization of the investigated matrices. The subsequent statistical multivariate data analysis enables a general identification of many deviations from the expected product composition. Besides the classical tests of authenticity of foods, a comprehensive analysis that also allows the detection of hazardous or safety-relevant manipulations and violations of the respective laws e.g. with regard to non-authorized food additives or a prohibited use of technological processes is of urgent need in food control. In the literature, several approaches are already pursuing the non-targeted observation of abnormalities in various foods covering a broad variety of analytical methods. This review highlights a current overview of the applicability of this approach using classic spectroscopic as well as spectrometric analytical techniques on the basis of examples of the three most investigated food matrices: honey, olive oil and wine. Furthermore, difficulties as well as challenges regarding the use of food fingerprinting in official food control are discussed.

Auditing local official food control: Perceptions of auditors and auditees

We surveyed the perceptions of regional food control officials (auditors) and municipal food control officials (auditees) on food control audits during 2007–2010 in Finland. According to the responses, the perceptions of auditors and auditees differed significantly. The regional officials had experienced the audits as clearly more useful and positive than the municipal officials and also found the current auditing system to be more suitable for evaluating municipal food control. The regional officials did, however, state that the audit results had not been adequately utilized in planning the guidance and education of professionals working in official food control. The municipal officials, in turn, were not satisfied with the expertise of the auditors concerning official food control in practice and did not find the audits very useful. The results suggest that more emphasis should be placed on peer-auditing to enhance the impact of food control audits.

Retail food stores' internet-based own-check databank records and health officers' on-site inspection results for cleanliness and food holding temperatures reveal inconsistencies

Official food control inspects retail food stores (food stores) regularly for compliance with food safety regulations. The health officer (inspector) inspects the food store's own-check (self-verification) and facilities and operations. The own-check inspection is usually performed on-site and includes the examination of own-check documentation. The chain-store groups (grocery multiple retailers) studied have developed an internet based own-check databank for documentation of own-check data for their own use, and also to enable official food control to make inspections via the internet. The chain-stores aim to speed up and possibly decrease the number of on-site inspections made by the official control in food stores. The purpose of this study was to investigate the accuracy and reliability of the own-check databank from the view of official food control.Fourteen food stores that represented three different national chain-store groups in a local municipality in Finland were included in the study. The own-check documentation from a 3-month period with regard to the receiving of products, cleanliness and temperatures of the refrigeration equipment was inspected by the official control via the internet based own-check databank. This was followed by an on-site inspection for comparison. The frequency of non-compliance for cleanliness recorded by the inspector on-site was significantly higher than the frequency of non-compliance recorded in the databank (Fisher's exact test, p < 0.05). On-site inspection observed non-compliance in temperatures (aberration >3 °C for at least 30 min) of refrigeration equipment for minced meat and processed fish products, determined by temperature data logger (24 h measurement), in 57.1% (8/14) of the stores. In contrast, no non-compliance regarding those same refrigeration equipment was recorded in the databank during a 3-month period. Discrepancies between the inspection results of cold holding and cleanliness in the databank and the on-site inspections were observed in food stores representing all three chain-store groups.The observed differences between the databank data and the on-site inspections, suggest that the frequency of on-site inspections should not be decreased or substituted by off-site databank inspections. Issues of on-site inspection and off-site databank inspection are discussed. Further, the study revealed serious problems in maintaining and monitoring of the temperature in refrigeration equipment in food stores.

Can analytical chemists do molecular biology? A survey of the up-skilling of the UK official food control system in DNA food authenticity techniques

That food accurately matches its description or labelling (food authenticity) is increasingly important to consumers and the agrifood sector. Its converse – mislabelling or misdescription or food fraud (when carried out for financial gain), is detrimental to both. A range of activities is used by enforcement authorities to establish authenticity and detect fraud including sampling and analysis. The UK Government, in a 20 year programme, has developed many novel analytical authenticity approaches including high resolution NMR, carbon isotope ratio analysis and DNA techniques. The flexibility, relatively lower costs and probative value of DNA methods render them particularly effective. However their deployment in the forensic environment of UK Official Food Control Laboratories (OCLs), staffed mainly by analytical chemists, required knowledge transfer (KT) of molecular biology techniques. The KT was carried out by the Food Standards Agency's Food Authenticity Programme (now transferred to Defra), and we present here the results of an assessment of its effectiveness. The findings highlight that the KT was well planned and highly effective. Competence in molecular biology in OCLs rose from 22% prior to the KT, based on qualifications and experience, to 69% after the KT based on embedding a suite of DNA methods in 11 out of 16 eligible laboratories. The transfer of 5 DNA methods (fish species, meat and exotic meat species, bushmeat species, Basmati rice, and orange juice adulteration with mandarin juice) have given OCLs an increased range of effectiveness with fish species identification having been particularly successfully applied and resulting in successful prosecutions of fraudulent activity. Given the current financial constraints in UK OCLs, a beneficial outcome has been a strategic refocussing of effort boosting enthusiasm and excitement for food authenticity issues. A further outcome of the transfer and evidence of the uptake of DNA technology has been the adoption of Real Time Polymerase Chain Reaction techniques by a critical mass (31.3%) of OCLs, permitting their advanced application to problematic authenticity issues such as the detection of adulteration of durum wheat pasta with common wheat, detection of meat ingredients in vegetarian foods, and the quantitative determination of GMOs in single ingredient foods such as pasta, rice and soya. Other recommendations arising out of the study are to adapt, to a lab-on-a-chip platform, DNA methods for pig and cattle breed authentication including wild boar, and an improved Basmati rice authentication. Finally, sustainable deployment of DNA methods to address food authenticity and fraud hinges on regulatory salience of the need for it and this, along with future priorities, should be kept under regular review.

A 5-Day Method for Determination of Soluble Silicon Concentrations in Nonliquid Fertilizer Materials Using a Sodium Carbonate-Ammonium Nitrate Extractant Followed by Visible Spectroscopy with Heteropoly Blue Analysis: Single-Laboratory Validation

A 5-day method for determining the soluble silicon (Si) concentrations in nonliquid fertilizer products was developed using a sodium carbonate (Na2CO3)-ammonium nitrate (NH4NO3) extractant followed by visible spectroscopy with heteropoly blue analysis at 660 nm. The 5-Day Na2CO3-NH4NO3 Soluble Si Extraction Method can be applied to quantify the plant-available Si in solid fertilizer products at levels ranging from 0.2 to 8.4% Si with an LOD of 0.06%, and LOQ of 0.20%. This Si extraction method for fertilizers correlates well with plant uptake of Si (r2 = 0.96 for a range of solid fertilizers) and is applicable to solid Si fertilizer products including blended products and beneficial substances. Fertilizer materials can be processed as received using commercially available laboratory chemicals and materials at ambient laboratory temperatures. The single-laboratory validation of the 5-Day Na2CO3-NH4NO3 Soluble Si Extraction Method has been approved by The Association of American Plant Food Control Officials for testing nonliquid Si fertilizer products.

Targeted multidimensional gas chromatography using a heart-cutting device and cryogenic focusing for the determination of benzophenone derivatives in foodstuffs

Photoinitiators are used to promote the polymerization process during the curing of varnishes or inks on cartonboard packaging. Depending on storage conditions and shelf life, these substances are able to migrate through the packaging layer into the foodstuff. This type of contamination phenomenon is therefore becoming a critical issue in terms of food safety. In order to tackle this problem, a fast and selective method was developed for the determination of benzophenone and three methylbenzophenone isomers in cereal-based foodstuffs and their cardboard packaging. Food samples or packages were efficiently extracted by pressurized liquid extraction using acetonitrile, and the extracts were directly injected onto the analytical system. The analysis was performed by multidimensional gas chromatography-mass spectrometry using a heart-cutting approach to reduce the background noise from complex matrices. The strategy employed two distinct cuts each containing its proper deuterated internal standard leading to accurate quantification. By integrating a cryofocusing effect, an enhancement in signal/noise ratio was achieved by a factor >10, which markedly decreased the sensitivity threshold. Moreover, baseline separation of the critical isomers allowed their unequivocal determination. The method was fully validated on cereal-based foodstuffs based upon an analysis of variance, and excellent performances were obtained at the decision limit making this method well suited for official food controls.

Preparation of Test Material and Evaluation of a Proficiency Test for Official Food Control Laboratories on the Determination of Polycyclic Aromatic Hydrocarbons in Baby Food

A proficiency test on the determination of polycyclic aromatic hydrocarbons (PAHs) was organized by the German National Reference Laboratory for PAH in 2010. The test samples were produced by spiking cereal-based instant baby food with PAHs at concentration levels between 0.6 and 3.8 μg/kg; homogeneity and stability of the test material were verified before sample dispatch. Twenty-one official laboratories from Germany and Austria participated in the test and the evaluation of the test was done by applying methods of robust statistics. The individual performance was assessed with the help of z-scores. As to the quantitative results, the dispersion of data for the most important group of benzo(a)pyrene (BaP), benz(a)anthracene (BaA), benzo(b)fluoranthene (BbF), and chrysene (CHR) appeared to be acceptable, with a relative robust standard deviation ranging from 13.2% for BbF to 26.7% for BaA. In total, the performance of one laboratory had to be rated as unsatisfactory because of a result for BaP outside the limits of tolerance. The methods applied in the test may be considered to be comparable, as no significant effects in the distribution of data could be attributed to certain analytical procedures.

Significance of official food control in food safety: Food business operators' perceptions

Finnish food business operators' (FBOs) opinions of the food control inspections performed by local authorities were evaluated, using a questionnaire. The production types of FBOs included were slaughterhouses, meat, fish and milk plants, egg-packing plants and storage facilities dealing with foods of animal origin. Based on a total of 459 responses, we noted that the impacts of official controls were considered valuable for food safety, since 78.8% of the respondents saw that the actions taken based on inspections had enhanced the safety of the products. The results also highlighted the importance of inspectors being familiar with the production processes to increase the efficacy of food control. More frequent visits by official inspectors correlated positively with FBOs' conceptions of noncompliances being relevant for food safety. The FBOs saw local inspectors as the most important sources of new information concerning food safety legislation and 89.1% of the respondents confirmed that discussions with local inspectors had helped them understand the food safety risks within their processes. We also noted that the bigger the FBO, the more clearly they seem to perceive the risks associated with their processes (Spearman's rank correlation coefficient r = 0.127, P = 0.009).

Parallelised real-time PCR for identification of maize GMO events

Identification of specific material derived from genetically modified organisms (GMO) present in food, feed or seed samples screened positive for the presence of genetic modification(s) is mandatory for the official food and feed control in the European Union. Since the introduction of regulation (EC) No 1829/2003 in 2004, the number of maize GMO events either approved in the EU or with a pending application grew constantly. By the sheer multitude of events and crossed events (stacks), maize poses a special challenge on official food and feed control. We developed a modular qualitative detection system for the parallel identification of maize GMO events to cope with the increasing number of GMO potentially present in routine samples. This system is based on validated real-time PCR assays in a microtitre plate format grouped modularly by crop species. The maize module identifies in parallel, i.e. simultaneously, 15 maize events and RoundupReady soy in a single analytical run of approximately 2 h. Maize modules can be conveniently prepared in advance and stored at −20 °C until use. Ready-to-use reference DNA mixtures serve as positive controls. The modular approach is flexible as it allows easy change or addition of individual detection reactions, if necessary, e.g. when new validated methods become available. 23 food, 14 feed and 8 seed samples were successfully analysed with the maize module. The parallel detection of nine different GMO maize and soy events in single routine samples demonstrated the usefulness of the parallelised modular approach for routine GMO analysis.