The new ISO 6579-1: A real horizontal standard for detection of Salmonella, at last!

Up to 2016, three international standard methods existed for the detection of Salmonella spp. in food, animal feed and samples from the primary production stage: ISO 6785:2001 for milk and milk products, ISO 6579:2002 for (other) food and animal feed and Annex D of ISO 6579:2007 for samples from the primary production stage. In 2009, an ISO/CEN working group started with the revision of ISO 6579:2002 with two main aims: combining the three aforementioned standards in one document and improving the information in ISO 6579:2002. Additionally it was decided to split ISO 6579 into three parts, where part 1 describes the detection, part 2 the enumeration by mini-MPN (published in 2012) and part 3 the serotyping of Salmonella (published in 2014). This paper describes the experiments and choices made for improving the part on detection of Salmonella (ISO 6579-1). The final voting stage on (draft) ISO 6579-1 was finished by the end of December 2016, with a positive outcome. Finally, a real horizontal standard became available for detection of Salmonella in food, animal feed, environmental samples in the area of food production and food handling and in samples from the primary production stage in 2017.

[New approach for managing microbial risks in food]. / Nouvelle approche de la gestion des risques microbiologiques dans les aliments.

The aim of the food legislation is to ensure the protection of human health. Traditionally, the food legislation requires food business operators to apply good hygiene practices and specific procedures to control foodborne pathogens. These regulations allowed reaching a high level of health protection. The improvement of the system will require risk-based approaches. Firstly, risk assessment should allow the identification of high-risk situations where resources should be allocated for a better targeting of risk management. Then, management measures should be adapted to the health objective. In this approach, the appropriate level of protection is converted intofood safety and performance objectives on the food chain, i.e., maximum microbial contamination to fulfil the acceptable risk level. When objectives are defined, the food business operators and competent authorities can identify control options to comply with the objectives and establish microbiological criteria to verify compliance with these objectives. This approach, described for approximately 10 years, operative thanks to the development of quantitative risk assessment techniques, is still difficult to use in practical terms since it requires a commitment of competent authorities to define the acceptable risk and needs also the implementation of sometimes complex risk models.

The quantitative and qualitative recovery of Campylobacter from raw poultry using USDA and Health Canada methods.

Harmonisation of methods between Canadian government agencies is essential to accurately assess and compare the prevalence and concentrations present on retail poultry intended for human consumption. The standard qualitative procedure used by Health Canada differs to that used by the USDA for both quantitative and qualitative methods. A comparison of three methods was performed on raw poultry samples obtained from an abattoir to determine if one method is superior to the others in isolating Campylobacter from chicken carcass rinses. The average percent of positive samples was 34.72% (95% CI, 29.2-40.2), 39.24% (95% CI, 33.6-44.9), 39.93% (95% CI, 34.3-45.6) for the direct plating US method and the US enrichment and Health Canada enrichment methods, respectively. Overall there were significant differences when comparing either of the enrichment methods to the direct plating method using the McNemars chi squared test. On comparison of weekly data (Fishers exact test) direct plating was only inferior to the enrichment methods on a single occasion. Direct plating is important for enumeration and establishing the concentration of Campylobacter present on raw poultry. However, enrichment methods are also vital to identify positive samples where concentrations are below the detection limit for direct plating.

Evaluation of the ISO 10273:2003 method for the isolation of human pathogenic Yersinia enterocolitica from pig carcasses and minced meat.

Pig carcass swabs (n = 254) and minced meat samples (n = 82) were examined for pathogenic Yersinia enterocolitica using different routinely used enrichment protocols. All samples were obtained in the context of the official Yersinia monitoring program in Belgium. In total, 28 carcasses (11.0%) were contaminated with Y. enterocolitica bioserotype 4/O:3 and one (0.4%) with bioserotype 2/O:9. Four minced meat samples (4.9%) tested positive for Y. enterocolitica bioserotype 4/O:3. Using the ISO 10273:2003 method, eight out of the 29 Yersinia-positive carcasses (27.6%) and none of the contaminated minced meat samples (0.0%) were detected. Reducing the enrichment time in PSB from 5 to 2 days increased the number of positive samples. Overall, enrichment in PSB at 25 °C recovered more positive carcasses and minced meat samples than selective enrichment and cold enrichment. As the exclusive use of the ISO 10273:2003 method results in a strong underestimation of Y. enterocolitica positive carcasses and minced meats, efforts are needed to optimize the current version of the ISO method. In addition, isolation of pathogenic Y. enterocolitica requires experience and the use of a stereomicroscope to avoid false negative results.

Inventory of microbial species with a rationale: a comparison of the IDF/EFFCA inventory of microbial food cultures with the EFSA Biohazard Panel qualified presumption of safety.

In order to provide a harmonised preassessment to support risk assessment performed by the European Food Safety Authority (EFSA), the Biohazard Panel in 2007 published guidelines for evaluation of the safety of a strain included in the food chain, the Qualified Presumption of Safety (QPS). Since 2008, the Biohazard Panel has published on a regular basis an update of the microbial strains submitted for approval and extends the list of species which have been granted QPS status. The International Dairy Federation (IDF) and the European Food and Feed Cultures Association (EFFCA) have, since 2002, been conducting a project on the safety demonstration of microbial food cultures (MFCs). Following the publication of IDF Bulletin 377-2002, an inventory of MFCs was published in IDF Bulletin 455-2012 and updated most recently in IDF Bulletin 495-2018. These two lists developed by EFSA (QPS) and IDF/EFFCA both propose as an outcome an inventory of microbial species that are safe for human consumption. To avoid confusion when these two inventories are compared, this review attempts to explain the rationale that was used to develop them and explain how the two lists should be understood.

Integration of Basic Knowledge Models for the Simulation of Cereal Foods Processing and Properties.

Cereal processing (breadmaking, extrusion, pasting, etc.) covers a range of mechanisms that, despite their diversity, can be often reduced to a succession of two core phenomena: (1) the transition from a divided solid medium (the flour) to a continuous one through hydration, mechanical, biochemical, and thermal actions and (2) the expansion of a continuous matrix toward a porous structure as a result of the growth of bubble nuclei either by yeast fermentation or by water vaporization after a sudden pressure drop. Modeling them is critical for the domain, but can be quite challenging to address with mechanistic approaches relying on partial differential equations. In this chapter we present alternative approaches through basic knowledge models (BKM) that integrate scientific and expert knowledge, and possess operational interest for domain specialists. Using these BKMs, simulations of two cereal foods processes, extrusion and breadmaking, are provided by focusing on the two core phenomena. To support the use by non-specialists, these BKMs are implemented as computer tools, a Knowledge-Based System developed for the modeling of the flour mixing operation or Ludovic®, a simulation software for twin screw extrusion. They can be applied to a wide domain of compositions, provided that the data on product rheological properties are available. Finally, it is stated that the use of such systems can help food engineers to design cereal food products and predict their texture properties.

Estimation and evaluation of management options to control and/or reduce the risk of not complying with commercial sterility.

In a previous study, a modular process risk model, from the raw material reception to the final product storage, was built to estimate the risk of a UHT-aseptic line of not complying with commercial sterility (Pujol et al., 2015). This present study was focused on demonstrating how the model (updated version with uncertainty and variability separated and 2(nd) order Monte Carlo procedure run) could be used to assess quantitatively the influence of management options. This assessment was done in three steps: pinpoint which process step had the highest influence on the risk, identify which management option(s) could be the most effective to control and/or reduce the risk, and finally evaluate quantitatively the influence of changing process setting(s) on the risk. For Bacillus cereus, it was identified that during post-process storage in an aseptic tank, there was potentially an air re-contamination due to filter efficiency loss (efficiency loss due to successive in-place sterilizations after cleaning operations), followed by B. cereus growth. Two options were then evaluated: i) reducing by one fifth of the number of filter sterilizations before renewing the filters, ii) designing new UHT-aseptic lines without an aseptic tank, i.e. without a storage period after the thermal process and before filling. Considering the uncertainty in the model, it was not possible to confirm whether these options had a significant influence on the risk associated with B. cereus. On the other hand, for Geobacillus stearothermophilus, combinations of heat-treatment time and temperature enabling the control or reduction in risk by a factor of ca. 100 were determined; for ease of operational implementation, they were presented graphically in the form of iso-risk curves. For instance, it was established that a heat treatment of 138°C for 31s (instead of 138°C for 25s) enabled a reduction in risk to 18×10(-8) (95% CI=[10; 34]×10(-8)), instead of 578×10(-8) (95% CI=[429; 754]×10(-8)) initially. In conclusion, a modular risk model, as the one exemplified here with a UHT-aseptic line, is a valuable tool in process design and operation, bringing definitive quantitative elements into the decision making process.

Characterizing uncertainty when evaluating risk management metrics: risk assessment modeling of Listeria monocytogenes contamination in ready-to-eat deli meats.

This report illustrates how the uncertainty about food safety metrics may influence the selection of a performance objective (PO). To accomplish this goal, we developed a model concerning Listeria monocytogenes in ready-to-eat (RTE) deli meats. This application used a second order Monte Carlo model that simulates L. monocytogenes concentrations through a series of steps: the food-processing establishment, transport, retail, the consumer's home and consumption. The model accounted for growth inhibitor use, retail cross contamination, and applied an FAO/WHO dose response model for evaluating the probability of illness. An appropriate level of protection (ALOP) risk metric was selected as the average risk of illness per serving across all consumed servings-per-annum and the model was used to solve for the corresponding performance objective (PO) risk metric as the maximum allowable L. monocytogenes concentration (cfu/g) at the processing establishment where regulatory monitoring would occur. Given uncertainty about model inputs, an uncertainty distribution of the PO was estimated. Additionally, we considered how RTE deli meats contaminated at levels above the PO would be handled by the industry using three alternative approaches. Points on the PO distribution represent the probability that - if the industry complies with a particular PO - the resulting risk-per-serving is less than or equal to the target ALOP. For example, assuming (1) a target ALOP of -6.41 log10 risk of illness per serving, (2) industry concentrations above the PO that are re-distributed throughout the remaining concentration distribution and (3) no dose response uncertainty, establishment PO's of -4.98 and -4.39 log10 cfu/g would be required for 90% and 75% confidence that the target ALOP is met, respectively. The PO concentrations from this example scenario are more stringent than the current typical monitoring level of an absence in 25 g (i.e., -1.40 log10 cfu/g) or a stricter criteria of absence in 125 g (i.e., -2.1 log10 cfu/g). This example, and others, demonstrates that a PO for L. monocytogenes would be far below any current monitoring capabilities. Furthermore, this work highlights the demands placed on risk managers and risk assessors when applying uncertain risk models to the current risk metric framework.