Applying the food safety objective and related standards to thermal inactivation of Salmonella in poultry meat

Cross-contamination events of Campylobacter spp. in domestic kitchens associated with consumer handling practices of raw poultry

Contaminated poultry is the major vehicle for consumer's exposure to Campylobacter. This study aimed to perceive potential cross-contamination events during preparation of raw poultry that can contribute to the spread of Campylobacter spp. in domestic kitchen environments and to understand consumers' meanings and justifications on preparation of a poultry dish at home. A total of 18 households were visited to observe consumers preparing a recipe that included poultry. Poultry samples and swabs from the kitchen surfaces and utensils, such as kitchen cloth, hand towel, sponge, cutting boards and the sink, were collected before and after food preparation and tested for the presence of Campylobacter spp. Genotypic characterization of 72 Campylobacter spp. isolates was carried out through Pulse-Field Gel Electrophoresis (PFGE). Fourteen chicken samples were contaminated with Campylobacter spp. (77.8%). Twelve consumers (66.6%) washed the chicken meat under running tap water and eight (44.4%) used cutting boards. Also, only five consumers washed their hands properly prior to or during meal preparation. Cross-contamination events were detected in four kitchens, between the raw chicken and two cutting boards, two sinks and one kitchen cloth. The poultry samples presented different levels of contamination (< 4.0 × 10¹ CFU/g to 2.2 × 10³ CFU/g), being some poultry with lower Campylobacter loads the origin of three cross-contamination events during food preparation. Both C. jejuni and C. coli were recovered. Molecular typing by PFGE showed a high diversity among the isolates. There were different explanations for the practice of cleaning and rinsing chicken, but, in general, it is an habit linked to what they have learned from their families. These results highlight the potential for the dissemination of Campylobacter strains in the domestic environment through the preparation of chicken meat and the need to raise awareness among consumers for an appropriate handling of raw poultry in order to decrease the risk of campylobacteriosis.

Cooking chicken at home: Common or recommended approaches to judge doneness may not assure sufficient inactivation of pathogens

About one third of foodborne illness outbreaks in Europe are acquired in the home and eating undercooked poultry is among consumption practices associated with illness. The aim of this study was to investigate whether actual and recommended practices for monitoring chicken doneness are safe. Seventy-five European households from five European countries were interviewed and videoed while cooking chicken in their private kitchens, including young single men, families with infants/in pregnancy and elderly over seventy years. A cross-national web-survey collected cooking practices for chicken from 3969 households. In a laboratory kitchen, chicken breast fillets were injected with cocktails of Salmonella and Campylobacter and cooked to core temperatures between 55 and 70°C. Microbial survival in the core and surface of the meat were determined. In a parallel experiment, core colour, colour of juice and texture were recorded. Finally, a range of cooking thermometers from the consumer market were evaluated. The field study identified nine practical approaches for deciding if the chicken was properly cooked. Among these, checking the colour of the meat was commonly used and perceived as a way of mitigating risks among the consumers. Meanwhile, chicken was perceived as hedonically vulnerable to long cooking time. The quantitative survey revealed that households prevalently check cooking status from the inside colour (49.6%) and/or inside texture (39.2%) of the meat. Young men rely more often on the outside colour of the meat (34.7%) and less often on the juices (16.5%) than the elderly (>65 years old; 25.8% and 24.6%, respectively). The lab study showed that colour change of chicken meat happened below 60°C, corresponding to less than 3 log reduction of Salmonella and Campylobacter. At a core temperature of 70°C, pathogens survived on the fillet surface not in contact with the frying pan. No correlation between meat texture and microbial inactivation was found. A minority of respondents used a food thermometer, and a challenge with cooking thermometers for home use was long response time. In conclusion, the recommendations from the authorities on monitoring doneness of chicken and current consumer practices do not ensure reduction of pathogens to safe levels. For the domestic cook, determining doneness is both a question of avoiding potential harm and achieving a pleasurable meal. It is discussed how lack of an easy "rule-of-thumb" or tools to check safe cooking at consumer level, as well as national differences in contamination levels, food culture and economy make it difficult to develop international recommendations that are both safe and easily implemented.

Risk assessment and risk management for safe foods: Assessment needs inclusion of variability and uncertainty, management needs discrete decisions

The introduction of relevant food safety changes in legislation, like time-temperature criteria for pasteurisation and sterilisation, microbiological criteria, HACCP and FSOs, generally took several decades. All these approaches have helped to define specific targets or systems to improve the management of food safety. More and more the measures could be related to specific efficiency in public health protection. With the use of quantitative risk assessment, theoretically the effect of all interventions on the final risk can be determined, which can help to design the appropriate controls in the food safety management system. In such an assessment in practice, however results have understandably large variability and also uncertainty. There is large variability and uncertainty in the biological parts of the assessment, the dose response (infectivity, human susceptibility) the micro-organism kinetics in the chain (growth, inactivation, stress response) and also in the more technological parts, the conditions in the chain and the consumer behaviour. Often the results of risk assessments are probability distributions of the variability in illness probability, also sometimes represented with their uncertainty. To make a link from these distributions to managerial decisions, that need to be black and white, should not be considered the job of risk managers. This link needs investment from both the assessor and the manager.

Selection of process conditions by risk assessment for apple juice pasteurization by UV-heat treatments at moderate temperatures

The effect of bactericidal UV-C treatments (254 nm) on Escherichia coli O157:H7 suspended in apple juice increased synergistically with temperature up to a threshold value. The optimum UV-C treatment temperature was 55 °C, yielding a 58.9% synergistic lethal effect. Under these treatment conditions, the UV-heat (UV-H55 °C) lethal variability achieving 5-log reductions had a logistic distribution (α = 37.92, β = 1.10). Using this distribution, UV-H55 °C doses to achieve the required juice safety goal with 95, 99, and 99.9% confidence were 41.17, 42.97, and 46.00 J/ml, respectively, i.e., doses higher than the 37.58 J/ml estimated by a deterministic procedure. The public health impact of these results is that the larger UV-H55 °C dose required for achieving 5-log reductions with 95, 99, and 99.9% confidence would reduce the probability of hemolytic uremic syndrome in children by 76.3, 88.6, and 96.9%, respectively. This study illustrates the importance of including the effect of data variability when selecting operational parameters for novel and conventional preservation processes to achieve high food safety standards with the desired confidence level.

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

In 2002, the Regulation (EC) 178 of the European Parliament and of the Council states that, in order to achieve the general objective of a high level of protection of human health and life, food law shall be based on risk analysis. However, the Commission Regulation No 2073/2005 on microbiological criteria for foodstuffs requires that food business operators ensure that foodstuffs comply with the relevant microbiological criteria. Such criteria define the acceptability of a product, a batch of foodstuffs or a process, based on the absence, presence or number of micro-organisms, and/or on the quantity of their toxins/metabolites, per unit(s) of mass, volume, area or batch. The same Regulation describes a food safety criterion as a mean to define the acceptability of a product or a batch of foodstuff applicable to products placed on the market; moreover, it states a process hygiene criterion as a mean indicating the acceptable functioning of the production process. Both food safety criteria and process hygiene criteria are not based on risk analysis. On the contrary, the metrics formulated by the Codex Alimentarius Commission in 2004, named Food Safety Objective (FSO) and Performance Objective (PO), are risk-based and fit the indications of Regulation 178/2002. The main aims of this review are to illustrate the key differences between microbiological criteria and the risk-based metrics defined by the Codex Alimentarius Commission and to explore the opportunity and also the possibility to implement future European Regulations including PO and FSO as supporting parameters to microbiological criteria. This review clarifies also the implications of defining an appropriate level of human protection, how to establish FSO and PO and how to implement them in practice linked to each other through quantitative risk assessment models. The contents of this review should clarify the context for application of the results collected during the EU funded project named BASELINE (www.baselineeurope.eu) as described in the papers of this special issue. Such results show how to derive POs for specific food/biological hazard combinations selected among fish, egg, dairy, meat and plant products.

Potential application of quantitative microbiological risk assessment techniques to an aseptic-UHT process in the food industry

Aseptic ultra-high-temperature (UHT)-type processed food products (e.g., milk or soup) are ready to eat products which are consumed extensively globally due to a combination of their comparative high quality and long shelf life, with no cold chain or other preservation requirements. Due to the inherent microbial vulnerability of aseptic-UHT product formulations, the safety and stability-related performance objectives (POs) required at the end of the manufacturing process are the most demanding found in the food industry. The key determinants to achieving sterility, and which also differentiates aseptic-UHT from in-pack sterilised products, are the challenges associated with the processes of aseptic filling and sealing. This is a complex process that has traditionally been run using deterministic or empirical process settings. Quantifying the risk of microbial contamination and recontamination along the aseptic-UHT process, using the scientifically based process quantitative microbial risk assessment (QMRA), offers the possibility to improve on the currently tolerable sterility failure rate (i.e., 1 defect per 10,000 units). In addition, benefits of applying QMRA are (i) to implement process settings in a transparent and scientific manner; (ii) to develop a uniform common structure whatever the production line, leading to a harmonisation of these process settings, and; (iii) to bring elements of a cost-benefit analysis of the management measures. The objective of this article is to explore how QMRA techniques and risk management metrics may be applied to aseptic-UHT-type processed food products. In particular, the aseptic-UHT process should benefit from a number of novel mathematical and statistical concepts that have been developed in the field of QMRA. Probabilistic techniques such as Monte Carlo simulation, Bayesian inference and sensitivity analysis, should help in assessing the compliance with safety and stability-related POs set at the end of the manufacturing process. The understanding of aseptic-UHT process contamination will be extended beyond the current "as-low-as-reasonably-achievable" targets to a risk-based framework, through which current sterility performance and future process designs can be optimised.

A probabilistic approach to determine thermal process setting parameters: application for commercial sterility of products

The objective of the probabilistic data analysis presented in this paper was to enable the thermal process to be set on actual data rather than on generic or conservative rules. The application was an ambient stable soup product, heated in a continuous UHT line. The data set comes from a decade of microbiological analysis: initial spore load and survival spore concentration after moderate heat-treatment (100°C for 15 min and 110°C for 15 min) have been enumerated in forty eight ingredients. The probabilistic analysis was carried out within a risk-based context, considering a Performance Objective, PO, set after the heat-treatment process and an initial spore contamination (H₀) at the ingredient mixing step. The probabilistic analysis was based upon Bayesian inference, chosen for its flexibility when dealing with censored data (some values were reported as less than 1 log cfu/g) and also for its ability to incorporate in the data analysis prior information. Beforehand, Z values around 10°C for aerobic bacterial spores, and log count error around 1 log, were assumed. The methodology and the results are reported using two ingredients (garlic and milk powder) illustrating the 'not detected' (censored data) issue and also the inter-ingredient variability. Indeed, Z was estimated to be 13.6°C (mean) for spores selected from garlic and 5.9°C for those selected from milk powder. Based upon a hypothetical soup recipe with these two ingredients, the sterilization value was estimated to be 13 min (95th percentile). The potential use of similar methodology to design and set the sterilization value for the thermal process of future products, is discussed.

Comparing the effect of various contamination levels for salmonella in chicken meat preparations on the probability of illness in belgium

At the urging of competent national authorities, a limited risk assessment on Salmonella in chicken meat preparations in Belgium was undertaken following a retail-to-table approach. The input distribution of Salmonella was based on surveillance data in Belgium. To analyze the relative impact of reducing the risk of salmonellosis associated with a decrease in the Salmonella contamination level, different distributions based on the actual situation but limiting the number of portions containing Salmonella at 1 CFU per 1, 10, and 25 g of meat were used in the quantitative microbial risk assessment model. The quantitative microbial risk assessment model also was run several times with a theoretical fixed input of Salmonella assuming all portions possessed the same fixed contamination level set at 1,000, 100, 10, and 1 CFU/g of meat and 1 CFU per 10, 25, 100, and 1,000 g of meat. With regard to the initial contamination level, the results indicate, both by the narrowing of the current distribution and by the fixed input, that especially the higher levels of contamination (>1 CFU/g) contribute to the increased risk for salmonellosis.