The challenge of defining risk-based metrics to improve food safety: inputs from the BASELINE project

Food Safety Controls during Bulk Food Preparation-An Observational Analysis

Seeing the palpable impact of food poisoning associated with catering operations, we surveyed caterers with and without past hygiene violations to examine staffing, food safety practices and correlations with microbial counts in food and the processing environment. Past infringements did not negatively impact the current execution of food safety measures nor the microbial quality of food. In preference to added stringencies for errant operators, we discuss alternative efforts to augment food safety, as well as the policy implications thereof.

Estimating Listeria monocytogenes Growth in Ready-to-Eat Chicken Salad Using a Challenge Test for Quantitative Microbial Risk Assessment

Currently, there is a growing preference for convenience food products, such as ready-to-eat (RTE) foods, associated with long refrigerated shelf-lives, not requiring a heat treatment prior to consumption. Because Listeria monocytogenes is able to grow at refrigeration temperatures, inconsistent temperatures during production, distribution, and at consumer's household may allow for the pathogen to thrive, reaching unsafe limits. L. monocytogenes is the causative agent of listeriosis, a rare but severe human illness, with high fatality rates, transmitted almost exclusively by food consumption. With the aim of assessing the quantitative microbial risk of L. monocytogenes in RTE chicken salads, a challenge test was performed. Salads were inoculated with a three-strain mixture of cold-adapted L. monocytogenes and stored at 4, 12, and 16 °C for eight days. Results revealed that the salad was able to support L. monocytogenes' growth, even at refrigeration temperatures. The Baranyi primary model was fitted to microbiological data to estimate the pathogen's growth kinetic parameters. Temperature effect on the maximum specific growth rate (μ_max ) was modeled using a square-root-type model. Storage temperature significantly influenced μ_max of L. monocytogenes (p < 0.05). These predicted growth models for L. monocytogenes were subsequently used to develop a quantitative microbial risk assessment, estimating a median number of 0.00008726 listeriosis cases per year linked to the consumption of these RTE salads. Sensitivity analysis considering different time-temperature scenarios indicated a very low median risk per portion (<-7 log), even if the assessed RTE chicken salad was kept in abuse storage conditions.

Performance Metrics for Slaughter and Dressing Hygiene at Australian Beef Export Establishments

ABSTRACT

A study was undertaken to examine hygienic control of the slaughter and dressing process for beef cattle at Australian export processing establishments. Samples were collected from two points during the process: immediately after hide removal and at the completion of dressing before the commencement of chilling. Hindquarter and forequarter samples were collected from 24 establishments, half of which (n = 12) used some form of microbial intervention (in addition to trimming). The overall contamination level on carcass sides was low and was reduced between hide removal and entering the chiller. The concentration and prevalence of indicator bacteria were higher on samples from hindquarters than on samples from forequarters. Application of an intervention, such as hot water, in addition to trimming resulted in a greater reduction in the concentration and prevalence of indicator bacteria than trimming alone, although the level of Escherichia coli and coliform bacteria on all samples was too low to allow meaningful comparisons to be made. Salmonellae were isolated from 2.09 and 0.56% of samples after hide removal and before chilling, respectively. Application of an intervention in addition to trimming did not result in a significant reduction (P = 0.4) of Salmonella prevalence on prechill carcasses. Low levels of bacteria were found on carcasses after hide removal. This, combined with small reductions as a result of trimming and sometimes other interventions, resulted in carcasses with very low levels of bacterial contamination. If performance metrics were to be applied to the slaughter and dressing process, a measure of the expected contamination at the end of the process would provide a more unequivocal measure of the process than either contamination on the carcass after hide removal or any reduction achieved as a result of the dressing process.

HIGHLIGHTS

The role of meat in foodborne disease: Is there a coming revolution in risk assessment and management?

Meat has featured prominently as a source of foodborne disease and a public health concern. For about the past 20 years the risk management paradigm has dominated international thinking about food safety. Control through the supply chain is supported by risk management concepts, as the public health risk at the point of consumption becomes the accepted outcome based measure. Foodborne pathogens can be detected at several points in the supply chain and determining the source of where these pathogens arise and how they behave throughout meat production and processing are important parts of risk based approaches. Recent improvements in molecular and genetic based technologies and data analysis for investigating source attribution and pathogen behaviour have enabled greater insights into how foodborne outbreaks occur and where controls can be implemented. These new approaches will improve our understanding of the role of meat in foodborne disease and are expected to have a significant impact on our understanding in the coming years.

Impact of Cooking Procedures and Storage Practices at Home on Consumer Exposure to Listeria Monocytogenes and Salmonella Due to the Consumption of Pork Meat

The objective of this research was to analyze the impact of different cooking procedures (i.e., gas hob and traditional static oven) and levels of cooking (i.e., rare, medium, and well-done) on inactivation of Listeria monocytogenes and Salmonella in pork loin chops. Moreover, the consumer's exposure to both microorganisms after simulation of meat leftover storage at home was assessed. The results showed that well-done cooking in a static oven was the only treatment able to inactivate the tested pathogens. The other cooking combinations allowed to reach in the product temperatures always ≥73.6 °C, decreasing both pathogens between 6 log₁₀ cfu/g and 7 log₁₀ cfu/g. However, according to simulation results, the few cells surviving cooking treatments can multiply during storage by consumers up to 1 log₁₀ cfu/g, with probabilities of 0.059 (gas hob) and 0.035 (static oven) for L. monocytogenes and 0.049 (gas hob) and 0.031 (static oven) for Salmonella. The key factors affecting consumer exposure in relation to storage practices were probability of pathogen occurrence after cooking, doneness degree, time of storage, and time of storage at room temperature. The results of this study can be combined with prevalence data and dose-response models in risk assessment models and included in guidelines for consumers on practices to be followed to manage cooking of pork meat at home.

Microbiological and Modeling Approach to Derive Performance Objectives for Bacillus cereus Group in Ready-to-Eat Salads

In this article, the performance objectives (POs) for Bacillus cereus group (BC) in celery, cheese, and spelt added as ingredients in a ready-to-eat mixed spelt salad, packaged under modified atmosphere, were calculated using a Bayesian approach. In order to derive the POs, BC detection and enumeration were performed in nine lots of naturally contaminated ingredients and final product. Moreover, the impact of specific production steps on the BC contamination was quantified. Finally, a sampling plan to verify the ingredient lots' compliance with each PO value at a 95% confidence level (CL) was defined. To calculate the POs, detection results as well as results above the limit of detection but below the limit of quantification (i.e., censored data) were analyzed. The most probable distribution of the censored data was determined and two-dimensional (2D) Monte Carlo simulations were performed. The PO values were calculated to meet a food safety objective of 4 log₁₀ cfu of BC for g of spelt salad at the time of consumption. When BC grows during storage between 0.90 and 1.90 log₁₀ cfu/g, the POs for BC in celery, cheese, and spelt ranged between 1.21 log₁₀ cfu/g for celery and 2.45 log₁₀ cfu/g for spelt. This article represents the first attempt to manage the concept of PO and 2D Monte Carlo simulation in the flow chart of a complex food matrix, including raw and cooked ingredients.

Extraction and downstream processing of plant-derived recombinant proteins

Plants offer the tantalizing prospect of low-cost automated manufacturing processes for biopharmaceutical proteins, but several challenges must be addressed before such goals are realized and the most significant hurdles are found during downstream processing (DSP). In contrast to the standardized microbial and mammalian cell platforms embraced by the biopharmaceutical industry, there are many different plant-based expression systems vying for attention, and those with the greatest potential to provide inexpensive biopharmaceuticals are also the ones with the most significant drawbacks in terms of DSP. This is because the most scalable plant systems are based on the expression of intracellular proteins in whole plants. The plant tissue must therefore be disrupted to extract the product, challenging the initial DSP steps with an unusually high load of both particulate and soluble contaminants. DSP platform technologies can accelerate and simplify process development, including centrifugation, filtration, flocculation, and integrated methods that combine solid-liquid separation, purification and concentration, such as aqueous two-phase separation systems. Protein tags can also facilitate these DSP steps, but they are difficult to transfer to a commercial environment and more generic, flexible and scalable strategies to separate target and host cell proteins are preferable, such as membrane technologies and heat/pH precipitation. In this context, clarified plant extracts behave similarly to the feed stream from microbes or mammalian cells and the corresponding purification methods can be applied, as long as they are adapted for plant-specific soluble contaminants such as the superabundant protein RuBisCO. Plant-derived pharmaceutical proteins cannot yet compete directly with established platforms but they are beginning to penetrate niche markets that allow the beneficial properties of plants to be exploited, such as the ability to produce 'biobetters' with tailored glycans, the ability to scale up production rapidly for emergency responses and the ability to produce commodity recombinant proteins on an agricultural scale.