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This study estimated the risk of listeriosis from Brazilian cheese consumption using quantitative microbial risk assessment (QMRA). Risks associated to consumption of two cheese types were assessed: artisanal ripened semi-hard cheese (produced with raw milk) and refrigerated fresh soft cheese (produced with pasteurized milk). The semi-hard cheese model predicted Listeria monocytogenes growth or decline during ripening, while the soft cheese model predicted pathogen growth during refrigerated storage. Semi-hard cheese modeling scenarios considered L. monocytogenes starting concentration from −2.4 to 6 log CFU/mL in raw milk and three ripening times (4, 22 and 60 days). Soft cheese modeling scenarios considered L. monocytogenes starting concentration from −2.4 to 4 log CFU/mL in milk. The inclusion of anti-listerial lactic acid bacteria (LAB) in cheeses was also examined. Risk of listeriosis due to consumption of soft cheese was 6000 and 190 times greater than that of semi-hard cheese, for general and vulnerable populations, respectively. Aging semi-hard cheese reduced risk, and risk was influenced by L. monocytogenes starting concentration. Aging cheese with inhibitory LAB for 22 days reduced risk over 4 million-fold when L. monocytogenes was assumed to be 6 log CFU/mL in raw milk. The inclusion of inhibitory LAB also reduced risk of listeriosis due to soft cheese consumption, but not as much as for semi-hard cheese. QMRA results predicted that consumption of contaminated cheeses can carry a high risk of listeriosis, especially for vulnerable populations. Scenario analyses indicated that aging of semi-hard cheese and inclusion of antimicrobial LAB mix in semi-hard and soft cheeses are effective risk mitigation measures. [ABSTRACT FROM AUTHOR]

The increase of soluble solids in milk by the addition of powdered products is a normal practice in the elaboration of yogurt in order to enhance viscosity, texture and sensory properties for the consumer. The purpose of this study was to evaluate the effect of adding jumbo squid ( Dosidicus gigas ) powder (protein content, 420 g/kg) on the aforementioned quality properties of yogurt. Six formulations of yogurt were prepared with the addition of 0, 1, 3, 5, 7 or 10 g/100 mL jumbo squid powder, plus one formulation with 3 g/100 mL maltodextrin. During fermentation, yogurts formulated with squid powder gradually achieved greater viscosity while producing both more acidity and at a higher rate than the controls. Apart from lower pH (hence, higher titratable acidity) and higher viscosity, the final enriched yogurts presented lower syneresis than the controls (p < 0.05). Although the highest viscosity (58.90 Pa.s) and the lowest syneresis (1.00%) was achieved by the yogurt with 10 g/100 mL jumbo squid powder, it was the treatment formulated with 3 g/100 mL (pH 4.31, acidity 0.85 g/100 g, viscosity 40.90 Pa.s and syneresis 9.10%) that kept constant sensory properties, as evaluated by the panelists, while improving some physical properties of the control yogurts. [ABSTRACT FROM AUTHOR]

A meta-analysis on the influence of the pasture on the lipid content and fatty acid profile in lamb meat was conducted. A total of 20 studies were selected and data on total lipid content, saturated, mono- and polyunsaturated fatty acids in lamb meat were extracted for two population groups, indoors, and pastured. Due to the high between-study heterogeneity, separate random-effects models were applied to the raw mean difference (effect size parameterization) for each of the outcomes. The results of the meta-analysis pointed that access to pasture tended to decrease the fat content in lamb, while increasing the saturated fatty acids (P < 0.05). The amounts of monounsaturated and n-6 polyunsaturated fatty acids were decreased (P < 0.05). On the other hand, grazing led to substantial increase in the content of n-3 polyunsaturated fatty acids, and decrease (P < 0.01) of the ratio n-6/n-3 in lamb meat, thus suggesting that pasture rearing can be recommended for improvement of meat dietetic quality. [ABSTRACT FROM AUTHOR]

In this work, all publicly-accessible published findings on Alicyclobacillus acidoterrestris heat resistance in fruit beverages as affected by temperature and pH were compiled. Then, study characteristics (protocols, fruit and variety, °Brix, pH, temperature, heating medium, culture medium, inactivation method, strains, etc.) were extracted from the primary studies, and some of them incorporated to a meta-analysis mixed-effects linear model based on the basic Bigelow equation describing the heat resistance parameters of this bacterium. The model estimated mean D * values (time needed for one log reduction at a temperature of 95 °C and a pH of 3.5) of Alicyclobacillus in beverages of different fruits, two different concentration types, with and without bacteriocins, and with and without clarification. The z T (temperature change needed to cause one log reduction in D -values) estimated by the meta-analysis model were compared to those (‘observed’ z T values) reported in the primary studies, and in all cases they were within the confidence intervals of the model. The model was capable of predicting the heat resistance parameters of Alicyclobacillus in fruit beverages beyond the types available in the meta-analytical data. It is expected that the compilation of the thermal resistance of Alicyclobacillus in fruit beverages, carried out in this study, will be of utility to food quality managers in the determination or validation of the lethality of their current heat treatment processes. [ABSTRACT FROM AUTHOR]

Abstract: Mixed Poisson distributions have been shown to be able to represent low microbial counts more efficiently than the lognormal distribution because of its greater flexibility to model microbial clustering even when data consist of a large proportion of zero counts. The objective of this study was to develop an alternative modelling framework for low microbial counts based on heterogeneous Poisson regressions. As an illustration, Poisson-gamma regression models were used to assess the effect of chilling on the concentration of total coliforms from beef carcasses (n = 600) sampled at eight large Irish abattoirs. Three Poisson-gamma and three zero-modified (hurdle and zero-inflated) models were appraised with a series of random-effects variants in order to extract any variability in microbial mean concentration, dispersion and/or proportion of zero counts. Models were compared and validated in their ability to predict the coliforms counts on carcasses after chilling. In all five test batches, the hurdle Poisson-gamma distributions predicted the observed post-chill counts closer than the Poisson-gamma distributions. This is justified by the better capacity of the hurdle model to represent a higher proportion of zero counts, which were in fact observed in the post-chill batches. Thus, with a coded variable (pre-chill/post-chill) as treatment, and extracting the significant variability of batches nested in abattoirs for the coliforms mean concentration (σ 2 u = 2.68), the dispersion measure (σ 2 v = 2.39) and the probability of zero counts (σ 2 w = 0.89), the validated hurdle Poisson-gamma model confirmed that chilling has a decreasing effect on the viability of coliforms from beef carcasses, and that the concentration is reduced by an average (pre-chill to post-chill) factor of 2.2 (95% CI: 2.15–2.24) at batch level. The model also indicated that chilling increases the odds of producing a zero count from a carcass swab in about 13.5 times, and that the higher the coliforms concentration in a batch, the weaker the effect that chilling has to reduce such contamination on the beef carcasses. [Copyright &y& Elsevier]

Abstract: As in many cases, pathogenic microorganisms contaminate the food material as clusters or group of individual cells; the effectiveness of sampling plans based on mixture distributions representing bacterial agglomeration was assessed. In general, sampling plans that do not take into account such consideration lead to higher probabilities of accepting defective lots. Since quite often no scientific data are available in order to determine the degree of over-dispersion or clustering of the target microorganisms, in this theoretical study we compare the variance-to-mean ratio and the reciprocal of the exponent k of the negative binomial distribution (NB) as measures of dispersion. The mixture Poisson-logarithmic (Plog) model is proposed as a special case of the NB distribution, where the bacterial clusters are Poisson distributed while the individuals in each cluster follow a logarithmic distribution. In order to describe microbial data characterised by an excess of zero counts (1−π), we assess the zero-inflated Poisson (ZIP) and zero-inflated negative binomial (ZINB) distributions as alternative statistical models. The Operating Characteristic (OC) curves generated on the basis of the zero-inflated distributions were compared for fixed values of the variance-to-mean ratio and the parameter π at any mean level of contamination and sample weight adopted. The results show that assuming fixed 1/k and π for the NB and ZIP distributions, respectively, both models converge to a Poisson distribution at the producer's quality level. In contrast, the consumer's quality level is highly affected by assuming fixed values of 1/k and π since it increases. The OC curves generated for the NB and ZIP distributions assuming fixed values of the variance-to-mean ratio at any mean level of contamination and sample weight adopted, reveal that both the consumer's and producer's quality level are affected, as they both increase. Within the ZINB distribution, a separate investigation is conducted to determine which parameters are mostly responsible for describing microbial over-dispersion. As a general conclusion, for the design of sampling plans based on any statistical distribution, OC curves that reflect microbial agglomeration should be constructed considering that variance is not constant but dependant on the level of microbial concentration of the lot. [Copyright &y& Elsevier]

We investigated the combined effect of three internal temperatures (60, 65 and 71.1°C) and four concentrations (0.0, 0.1, 0.5 and 1% vol/wt) of two natural antimicrobials on the heat resistance of an eight-strain cocktail of Salmonella serovars in chicken meat. A complete factorial design (3×4×4) was used to assess the effects and interactions of heating temperature and the two antimicrobials, carvacrol and cinnamaldehyde. The 48 variable combinations were replicated to provide a total of 96 survivor curves from the experimental data. Mathematical models were then developed to quantify the combined effect of these parameters on heat resistance of starved Salmonella cells. The theoretical analysis shows that the addition of plant-derived antimicrobials overcomes the heat resistance of starvation-stressed Salmonella in ground chicken meat. The influence of the antimicrobials allows reduced heat treatments, thus reducing heat-induced damage to the nutritional quality of ground-chicken products. Although the reported omnibus log-linear model with tail and the omnibus sigmoid model could represent the experimental survivor curves, their discrepancy only became apparent in the present study when lethality times (D-values and t 7.0) from each of the models were calculated. Given the concave nature of the inactivation curves, the log-linear model with tail greatly underestimates the times needed to obtain 7.0 log lethality. Thus, a polynomial secondary model, based on the sigmoid model, was developed to accurately predict the 7.0-log reduction times. The three-factor predictive model can be used to estimate the processing times and temperatures required to achieve specific log reductions, including the regulatory recommendation of 7.0-log reduction of Salmonella in ground chicken. [ABSTRACT FROM AUTHOR]

Abstract: The effect of chilling on the occurrence of Salmonella on pig carcasses was investigated at study, abattoir and batch level by meta-analysis. Both the fixed-effects and random-effects model confirmed (p<0.05) the significant effect of chilling in decreasing Salmonella occurrence on pig carcasses; although the random-effects solution was preferred to account for the significant variability in effect size (p<0.001) estimated from the 13 primary studies considered, the 32 abattoirs surveyed, and the 51 sampled batches. Conservatively, it can be said that chilling reduces the Salmonella incidence on pig carcasses by a mean ratio of ~1.6 (95% CI: 1.0–2.6). Multilevel meta-analysis models investigating study characteristics that could explain the heterogeneity (τ 2) in the true effect size among primary studies (τ 2 =0.578), among surveyed abattoirs (τ 2 =0.431), and among sampled batches (τ 2 =0.373), revealed that study size (represented by the moderating variables of ‘total sample size’ and ‘number of batches sampled in an abattoir’) and ‘carcass swabbed area’ have a significant impact (p<0.05) on the measured effect size of chilling. The fact that swabbed area explained between 56 and 62% and total sample size between 23 and 38% of the total heterogeneity in the chilling true effect size, indicates that differences in experimental design greatly affect our substantive conclusion about the effect of chilling on Salmonella occurrence. This inconsistency to elucidate the effect of chilling arises because of the many factors influencing both the performance of the chilling operation and the measurement itself. Meta-analysis was not only instrumental to show that small-size studies (i.e., only one batch sampled per abattoir, total number of sampled carcasses per batch<50) and small swabbed areas (<100cm2) lead to imprecise and even conflicting conclusions, but most importantly, enabled definition of the characteristics of a well-designed study having a minimum statistical power to produce precise results. A sound experimental design derived by multilevel meta-analysis consists of swabbing carcass areas of at least 500cm2 from 25 pre-chill and 25 post-chill carcasses from a single production batch, with a minimum of two batches sampled per surveyed abattoir. If the survey were to be conducted in more than one abattoir, the total sample size should not be less than 400. Two methods to test for publication bias, a common problem in meta-analysis, suggested that whilst the presence of unpublished small-size studies is probable, it is not likely that this would significantly bias the overall chilling effect estimated in this study. [Copyright &y& Elsevier]

Abstract: This study proposes a novel step-wise methodology for the derivation of a sampling plan by variables for food production systems characterised by relatively low concentrations of the inspected microorganism. After representing the universe of contaminated batches by modelling the between-batch and within-batch variability in microbial counts, a tolerance criterion defining batch acceptability (i.e., up to a tolerance percentage of the food units having microbial concentrations lower or equal to a critical concentration) is established to delineate a limiting quality contour that separates satisfactory from unsatisfactory batches. The problem consists then of finding the optimum decision criterion – arithmetic mean of the analytical results (microbiological limit, mL ) and the sample size (n) – that satisfies a pre-defined level of confidence measured on the samples'' mean distributions from all possible true within-batch distributions. This is approached by obtaining decision landscape curves representing collectively the conditional and joint producer''s and consumer''s risks at different microbiological limits along with confidence intervals representing uncertainty due to the propagated between-batch variability. Whilst the method requires a number of risk management decisions to be made such as the objective of the sampling plan (GMP-based or risk-based), the modality of derivation, the tolerance criterion or level of safety, and the statistical level of confidence, the proposed method can be used when past monitoring data are available so as to produce statistically-sound dynamic sampling plans with optimised efficiency and discriminatory power. For the illustration of Enterobacteriaceae concentrations on Irish sheep carcasses, a sampling regime of n =10 and mL =17.5CFU/cm2 is recommended to ensure that the producer has at least a 90% confidence of accepting a satisfactory batch whilst the consumer at least a 97.5% confidence that a batch will not be mistakenly accepted in the long run. Unlike classical sampling plan theory, which derives sampling plans solely based on a tolerance criterion, our sampling plans are more informative and amenable to be updated as they take into account the actual microbial concentrations of the food process, enabling the same methodology to be used to construct control charts. [Copyright &y& Elsevier]

Abstract: An assessment of the performance of an EC 1441/2007 microbiological criterion was conducted based on the new Poisson-gamma modelling framework characterising within-batch and between-batch variability in Enterobacteriaceae counts on pre-chill sheep carcasses. Since the model does not assume within-batch constant variance but instead represents an association between within-batch means and dispersion measures, the operating characteristic (OC) curves could be constructed with confidence intervals arising from the uncertainty in the within-batch spread conditional to the within-batch mean. The model predicted that in Ireland the microbiological criterion would categorise the hygiene of sheep processing as ‘satisfactory’ (below mT  = 1.5 log CFU/cm2) and ‘acceptable’ (between m T and MT  = 2.5 log CFU/cm2) on average 98.6% (95% CI: 84.6–100%) and 1.4% (95% CI: 0–14.8%) of the times a batch is tested by taking the mean log of five individual samples. On average, batches produced beyond ∼260 CFU/cm2 and ∼1660 CFU/cm2 of mean Enterobacteriaceae concentration would have at least 95% confidence of being spotted by the ‘acceptable’ and the ‘unsatisfactory’ criterion (>MT), respectively, although under the existing contamination levels virtually no tested batch will prompt the revision of hygiene procedures in the Irish sheep abattoirs. This work proposes the definition of microbiological limits in arithmetic means, as by simulation this approach was found to lead to the definition of sampling plans that are both more effective (i.e., reduced uncertainty around the acceptance probabilities) and with more discriminatory power than those based on the common mean log scale. Based on the relatively low levels of Enterobacteriaceae on Irish pre-chill sheep carcasses (4.5 CFU/cm2), a new lower limit of 60 CFU/cm2 derived from the arithmetic means approach has been suggested so that batches of up to the 95th percentile of mean concentrations (∼22 CFU/cm2) be considered as originating from a ‘satisfactory’ process with at least 95% confidence. This more conservative implies that 1.5% (95% CI: 0–16.3%) of the tested batches will emit a warning signal in the long run. Increasing sample size however will not affect the average probability of warning but will have an impact on reducing the uncertainty resulting from the between-batch variability. [Copyright &y& Elsevier]

Abstract: In modelling risk management strategies (i.e., acceptance sampling plans, statistical process control), two basic assumptions have been normally made: that the true concentration of microorganisms are log-normally distributed within a batch, and that the variance of the samples is the same for a little or highly contaminated lot. Within a heterogeneous Poisson theoretical framework, these two assumptions have been evaluated by characterising the between-batch and within-batch variability in microbial counts. To this effect, three variants of regressions (random effects for within-batch means only, correlated and uncorrelated random effects for within-batch means and spread measures) based on the Poisson-gamma (m,1/k) and the Poisson-lognormal (μ,σ) models were fitted to six microbial data sets of TVC, coliforms and Escherichia coli on pre-chill and post-chill beef carcasses sampled from different production batches. For the high counts data sets, the Poisson-lognormal regression with random effects for within-batch means (μ) provided a better model for the estimation of the within-batch and between-batch standard deviation; whereas for the low counts data sets, the Poisson-gamma regressions were superior for the characterisation of within-batch and between-batch variability. However, the selection of a complex Poisson-gamma model with correlated (m,1/k) random effects against a simple Poisson-gamma with variable means (m) depended on the extent of between-batch heterogeneity in the dispersion factor 1/k. The need to introduce the between-batch variability notion in risk management was further highlighted by assessing the real effectiveness of a hypothetical sampling plan operating under the best-fit correlated random effects Poisson-gamma approach, whereby the within-batch dispersion factor was variable and conditional on the within-batch mean. [Copyright &y& Elsevier]

Abstract: The choice of statistical distributions characterising microbial counts is essential in risk assessment and risk management. While the lognormal distribution has been long used to directly model the microbial data obtained from food samples, it does not allow for complete absence of microorganisms in a sample. Within a heterogeneous Poisson theoretical interpretation, a gamma or a lognormal population distribution for the unknown microbial concentration and a Poisson measurement distribution produces a discrete Poisson-gamma (λ, 1/k) or a Poisson-lognormal (μ,σ) distribution of observed plate counts. The capability of both distributions to deal with clustering was compared using six data sets of variable proportion of zero counts: total viable counts, coliforms and Escherichia coli on pre-chill and post-chill beef carcasses. Whereas the Poisson-lognormal distribution fitted better to the high counts data sets, the Poisson-gamma distribution represented the low counts data sets (13–81% zero counts) by far better than the Poisson-lognormal – which invariably tended to have a longer tail, an overestimated mean log and a lower predicted probability of zero counts. The inverse close relationship between the observed proportion of zero counts in the data set and the fitted dispersion factor 1/k suggested the possibility of obtaining a first approximation of 1/k by this means. Finally, in absence of zero counts, it was demonstrated that fitting a Poisson-lognormal to the observed plate count data can be closely approximated by the common practice of fitting a simple normal distribution to the back-calculated ‘unobserved’ mean concentrations in log CFU/g. [Copyright &y& Elsevier]

Abstract: This communication deals with the use of meta-analysis as a valuable tool for the synthesis of food safety research, and in quantitative risk assessment modelling. A common methodology for the conduction of meta-analysis (i.e., systematic review and data extraction, parameterisation of effect size, estimation of overall effect size, assessment of heterogeneity, and presentation of results) is explained by reviewing two meta-analyses derived from separate sets of primary studies of Salmonella in pork. Integrating different primary studies, the first meta-analysis elucidated for the first time a relationship between the proportion of Salmonella-carrier slaughter pigs entering the slaughter lines and the resulting proportion of contaminated carcasses at the point of evisceration; finding that the individual studies on their own could not reveal. On the other hand, the second application showed that meta-analysis can be used to estimate the overall effect of a critical process stage (chilling) on the incidence of the pathogen under study. The derivation of a relationship between variables and a probabilistic distribution is illustrations of the valuable quantitative information synthesised by the meta-analytical tools, which can be incorporated in risk assessment modelling. Strengths and weaknesses of meta-analysis within the context of food safety are also discussed. [Copyright &y& Elsevier]

Abstract: A stochastic consumer-phase exposure assessment modelling the transport and refrigeration modules indicated that the concentration of Salmonella typhimurium in contaminated Irish pork sausages prior to cooking was on average 1.79logCFU/g (95% CI: 1.22–2.42logCFU/g); and that, out of 100 000 refrigerated sausage packs, an average of ∼83 packs (95% CI: 73–96) would have hazardous mean Salmonella concentrations above 3logCFU/g prior to cooking (Freq(Y >3)). Scenario analysis revealed that a decrease in the refrigeration temperature by 2°C and a decrease of the initial prevalence of S. typhimurium by half (∼0.02) would have a comparable level of reduction in Freq(Y>3) (∼23–43 packs per 100000 packs), while a decrease in the storage time by half would have by far the highest level of reduction (Freq(Y >3)=∼2–7 packs per 100000 packs). Finally, a practical method for the simulation of the product’s temperature profile in cold storage has been proposed based on the application of heat transfer equations and actual product’s temperature history data. [ABSTRACT FROM AUTHOR]

Prevalence and counts of Salmonella Typhimurium in fresh pork sausage packs at the point of retail were modeled by using Irish and United Kingdom retail surveys' data. A methodology for modeling a second-order distribution for the initial Salmonella concentration (λ0) in pork sausage at retail was presented considering the uncertainty originated from the most-probable-number (MPN) serial dilutions. A conditional probability of observing the tube counts given true Salmonella concentration in a contaminated pack was built from the MPN triplets of every sausage tested. A posterior distribution was then modeled under the assumption that the counts from each of the portions of sausage mix stuffed into casings (and subsequently packed) are Poisson distributed. In order to model the variability of λ0 among contaminated sausage packs, MPN uncertainties were propagated to a predefined lognormal distribution. Because the sausage samples from the Irish survey were frozen prior to MPN analysis (which is expected to cause reduction in viable cells), the resulting distribution for λ0 appeared greatly underestimated (mean: 0.514 CFU/g; 95% confidence interval [CI]: 0.02 to 2.74 CFU/g). The L0 distribution produced with the United Kingdom survey data (mean: 69.7 CFU/g; 95% CI: 15 to 200 CFU/g) was, however, more conservative, and is to be used along with the fitted distribution for prevalence of Salmonella Typhimurium in pork sausage packs in Ireland (gamma[37.997, 0.0013]; mean: 0.046; 95% CI: 0.032 to 0.064) as the main inputs of a stochastic consumer-phase exposure assessment model. [ABSTRACT FROM AUTHOR]

Abstract: In many cases, microbial data are characterised by a relatively high proportion of zero counts, as occurs with some hygiene indicators and pathogens, which complicates the statistical treatment under the assumption of log normality. The objective of this work was to introduce an alternative Poisson-based distribution framework capable of representing this kind of data without incurring loss of information. The negative binomial, and two zero-modified parameterisations of the Poisson and negative binomial distributions (zero-inflated and hurdle) were fitted to actual zero-inflated bacterial data consisting of total coliforms (n =590) and Escherichia coli (n =677) present on beef carcasses sampled from nine Irish abattoirs. Improvement over the simple Poisson was shown by the simple negative binomial (p =0.426 for χ 2 test for the coliforms data) due to the added heterogeneity parameter, although it slightly overestimated the zero counts and underestimated the first few positive counts for both data sets. Whereas, the zero-modified Poisson could not cope with the data over-dispersion in any of its parameterisations (p <0.001 for χ 2 tests), the parameterisations of the zero-modified negative binomial presented differences in fit due to approximation errors. While the zero-inflated negative binomial parameterisation was apparently reduced to a negative binomial due to a non-convergence of the logit parameter estimate, the goodness of fit of the hurdle negative binomial parameterisation indicated that for the data sets under evaluation (coliforms data with ~13% zero counts and E. coli data with ~42% zero counts), the zero-modified negative binomial distribution was comparable to the simpler negative binomial distribution. Thus, bacterial data consisting of a considerable number of zero counts can be appropriately represented by using such count distributions, and this work serves as the starting point for an alternative statistical treatment of this kind of data and stochastic risk assessment modelling. [Copyright &y& Elsevier]

Abstract: The objective of this work was to assess the crumb grain appearance of bread loaves prepared with four organic flours (11.3–12.4% protein content) in comparison with a control bread prepared with non-organic flour (12.4% protein content), by means of three statistical and one spectral grey-level image texture analysis methods. Stepwise-selected textural features independently extracted from each method could successfully distinguish 94–97% of the non-organic bread’s crumb grain images, and could classify 76–83% of the organic bread’s crumb grain images into their respective flour types using cross-validation. The statistical texture analysis methods (explained variance 91–96%) depicted the bread crumb visual texture better than the spectral method (explained variance 80%). Factor analysis performed over the highest discriminant textural features identified three major components: grain coarseness, heterogeneity and isotropy, being the last component extracted only from the spectral method. This model showed that crumb grain of organic breads was variably heterogeneous, coarse and, in some cases, with a high degree of isotropy, since their cells were much more rounded than the non-organic bread’s crumb cells. [Copyright &y& Elsevier]

Abstract: The suitability of seven thresholding methods (six algorithms: isodata, Otsu, minimum error, moment-preserving, Pun and fuzzy; and a manual method) to consistently segment bread crumb images was investigated in comparison with the previously reported k-means clustering technique. Thresholding performance was assessed by two criteria: uniformity and busyness of the binary images. Crumb features (cell density, mean cell area, cell uniformity and void fraction) were computed for each optimal threshold on 135 bread slice images. Slight variations in threshold led to substantial variations in crumb feature values, with cell uniformity and void fraction being more sensitive than the others. The manual method was inadequate for quantification of cell uniformity and void fraction. The fuzzy, Otsu, isodata and moment-preserving methods yielded good and consistent binary images. Although the fuzzy method showed relatively higher amount of busyness than the other methods, it was able to perform well on images with large void areas. [Copyright &y& Elsevier]

• Lamb meat quality of three Italian and German breeds was evaluated. • Meat of lambs reared in extensive system had the lowest SFA content. • Meat of lambs reared in extensive system had the highest n-3 PUFA content. • Meat from the Italian Sambucana lambs presented the lowest cholesterol content. • Meat from the three breeds was of high quality with low fat content. The aim of this study was to evaluate and compare the quality characteristics, chemical composition and lipid profile of lamb meat from Italian (Biellese and Sambucana) and German (Texel-Merino-Blackhead-Charollais [TMBC]) breeds reared in extensive and semi-extensive production systems. Meat samples from 89 animals were analysed. The meat of the lambs from semi-intensively reared Biellese, and extensively reared Sambucana and TMBC breeds produced lean meat, with slightly higher intramuscular fat content in TMBC. The latter also produced meat of darker colour (P < 0.05) and higher protein content (P < 0.05). The meat of Sambucana lambs presented the lowest total cholesterol content (P < 0.05). The fatty acid profile of the meat showed a clear advantage of both extensively reared breeds, which had substantially lower proportion of saturated but higher of polyunsaturated fatty acids, particularly n-3 (P < 0.05). The beneficial effect of the extensive rearing conditions was associated with lower n-6/n3 ratio, and atherogenic and thrombogenic indices, thereby suggesting that production system can be used successfully to modify the fatty acid profile to achieve a positive effect for the human health. [ABSTRACT FROM AUTHOR]

• Quality of lamb meat from 8 European breeds raised in 10 farms was assessed. • Carcass weight and fat content determined colour, cooking loss, TBARs and tenderness. • TBARs was driven by all meat's intrinsic properties studied except Ph. • Lamb meat from extensive systems required longer maturation for tenderization. • CIE b* and shear work were the attributes least affected by the intrinsic properties. The sustainability of the European sheep farming sector can be ensured through the high and consistent quality of products, although the concept of meat quality, being multifaceted, is challenging to keep up by farmers and producers. The objectives of this study were (i) to evaluate quality attributes (CIE L*, a*, b*, lipid oxidation, cooking loss and Warner-Bratzler texture test) of lamb meat during cold storage originating from eight European breeds raised under their normal production systems (n = 292 lambs); and (ii) to elucidate the influence of storage and intrinsic properties (cold carcass weight [CCW], ultimate pH [pH 24 ], water activity [a w ], and proximate composition) on the aforementioned quality attributes measured on the 3rd, 9th and 15th day post slaughter. All meat quality properties displayed a high variability due to the breed × production systems, although, as a whole, L*, a*, b*, TBARs and cooking loss increased during storage (P < 0.001), whereas the tenderisation process was of non-linear decay nature (P = 0.001). While production system – taken across breeds – was not found to affect meat cooking losses, it heavily influenced CCW, producing intensive systems heavier (P < 0.001) carcasses (21.4 kg) than those raised in semi-extensive (14.9 kg) and extensive systems (13.8 kg). On the 15th day of storage, TBARs from intensive systems was significantly (P < 0.001) higher than those of extensively raised lambs (0.839 mg MDA/kg vs. 0.299 mg MDA/kg, respectively). Although the extensive and semi-extensive systems initially produced less tender meat (P < 0.05) than intensive systems, on the 15th day of storage, meat from extensive (23.4 N/cm2) and semi-extensive systems (24.4 N/cm2) presented as good tenderness quality (P < 0.10) as that of the intensive systems (22.1 N/cm2). Within breed × production systems, higher CCW or intramuscular fat was associated to darker meat (P < 0.001 and P = 0.014), higher redness (P < 0.001 for both), greater lipid oxidation (P = 0.016 and P < 0.001), and lower slope (P = 0.014 and P = 0.004) and force (P = 0.027 and P = 0.001). The only intrinsic property that heavily affected most of the quality attributes was ash content, since meat of higher ash content presented higher luminosity (P = 0.008), and lower redness (P < 0.001), yellowness (P < 0.001), TBARS (P < 0.001), cooking loss (P = 0.002) and tenderness (P < 0.001). The elucidation of the impact of intrinsic properties on the lamb meat quality attributes during storage can help breeders and producers modify current flock management, feeding strategies and pre-slaughter and slaughter practices towards quality improvement or meeting particular consumers' demands. [ABSTRACT FROM AUTHOR]

In this pilot study, we compared the metagenomic profiles of different types of artisanal fermented meat products collected in Italy, Greece, Portugal, and Morocco to investigate their taxonomic profile, also in relation to the presence of foodborne pathogens and antimicrobial resistance genes. In addition, technical replicates of the same biological sample were tested to estimate the reproducibility of shotgun metagenomics. The taxonomic analysis showed a high level of variability between different fermented meat products at both the phylum and genus levels. Staphylococcus aureus was identified with the highest abundance in Italian fermented meat; Escherichia coli in fermented meat from Morocco; Salmonella enterica in fermented meat from Greece; Klebsiella pneumoniae and Yersinia enterocolitica in fermented meat from Portugal. The fungi Aspergillus, Neosartoria, Emericella, Penicillum and Debaryomyces showed a negative correlation with Lactococcus, Enterococcus, Streptococcus, Leuconostoc and Lactobacillus. The resistome analysis indicated that genes conferring resistance to aminoglycoside, macrolide, and tetracycline were widely spread in all samples. Our results showed that the reproducibility between technical replicates tested by shotgun metagenomic was very high under the same conditions of analysis (either DNA extraction, library preparation, sequencing analysis, and bioinformatic analysis), considering both the degree of overlapping and the pairwise correlation. [ABSTRACT FROM AUTHOR]

• Quality characteristics of lamb meat from eight European breeds was characterised. • Proximate composition of lamb meat was affected by production system. • Substantial variability in the levels of spoilage bacteria in lamb meat was found. • Growth of spoilage bacteria in meat was exarcerbated by higher ultimate pH. • Meat from heavier lamb carcasses underwent a slower spoilage process. Although sheep meat has a small share of ∼1.5 % of the total meat production in the EU, sheep farming is of great importance to rural development and the environment. Enhancing the quality of lamb meat of local breeds is essential to ensure both profitability for sheep producers and the conservation of endangered breeds. This study aimed to (i) characterise the evolution of spoilage microorganisms in refrigerated vacuum-packed lamb meat from a total of 10 farms housing 8 local breeds of Portuguese, Spanish, Italian and Slovenian origin raised in intensive, extensive or semi-extensive regime; and (ii) elucidate how intrinsic properties of meat can affect its microbial spoilage. Cold carcass weight (CCW), ultimate pH (pH 24) and proximate analysis were quantified on carcass/meat from each of the 285 animals raised and slaughtered for this purpose; while mesophiles, lactic acid bacteria, Pseudomonas spp. and psychrotrophic bacteria were enumerated during 15-day storage at 4 °C. Substantial variability in all attributes were found between the ten farms. CCW of intensively-raised lambs (21.4 kg; 95 % CI: 20.6–22.1 kg) were higher (p < 0.05) than the ones in semi-extensive regime (14.9 kg; 95 % CI: 14.4–15.4 kg), and in turn these were heavier (p < 0.05) than the extensively raised lambs (12.4 kg; 95 % CI: 12.0–12.7). Mean contents of protein (76.5–87.4% db), fat (3.78–13.1% db) and ashes (4.62–5.65% db) in lamb meat were highly dependent on the farm. Although meat from some farms was associated to higher microbial levels, in general, microbial growth was found to be modulated by intrinsic properties of meat. Higher pH 24 (p < 0.05), moisture (p < 0.05), protein content (p < 0.05) and ashes content (p < 0.01) accelerated spoilage rate; whereas meat from heavier carcasses (p < 0.001) and of higher fat content (p < 0.01) presented slower growth of spoilage bacteria. In order to improve the microbial quality of lamb meat, animal handling must be enhanced to minimise pre-slaughter stress; slaughtering practices and hygiene must be improved; and a carcass classification system could be adopted towards the selection of fatter animals and chilled carcasses of optimal pH 24. [ABSTRACT FROM AUTHOR]

The management of Heat Resistant Moulds (HRMs) is considered a great challenge for the juice fruit industry. Neosartorya , Byssochlamys and Talaromyces are three out of the main genera isolated from fruit juices that show great resistance to heat treatments. Several inactivation parameters can be found in the literature, however all of them were carried out in specific food matrices and using diverse inactivation methods. Thus, this meta-analysis study synthesizes the thermal resistance parameters of the three HRMs by adjusting extended Bigelow-based meta-regression models to data on inactivation experiments conducted in different liquid media. The meta-analytical data, extracted from publications between 1969 and 2017, was composed of decimal reduction time (D), inactivation method, temperature of inactivation, pH, °Brix, age of spores, and type of medium (model, juice, concentrates). Pooled D* values (D at 90 °C, pH 3.5 and 12° Brix) were estimated for B. fulva (1.95 min; 95% CI: 1.21–3.11 min), Talaromyces (4.03 min; 95% CI: 3.43–4.74 min), Neosartorya (0.5.35 min; 95% CI: 4.10–7.08 min), and B. nivea (10.32 min; 95% CI: 5.81–18.4 min). It was found that increasing the soluble solids in concentrates tends to cause a lower decrease in the heat resistance of Neosartorya and Talaromyces than increasing the soluble solids in model liquid or juices (p = 0.001; 0.012). In general, the screw-capped tubes and three neck round inactivation methods render higher D* values (p < 0.05) than the thermal death tubes, the polyethylene bag and the capillary methods. Spores of Talaromyces (overall z pH = 7.56; 95% CI: 5.13–13.5) and Neosartorya (overall z pH = 7.07; 95% CI: 5.04–10.8) appear to be more thermal sensitive to a decrease in medium pH than spores of Byssochlamys (overall z pH = 4.34; 95% CI: 3.20–6.73). The meta-regression models presented in this study can be valuable for estimating pooled inactivation kinetic parameters to be used by the fruit juice industry in the management of thermal processes and in the determination of shelf-life. • Pooled D 90°C * were higher for B. nivea > Neosartorya > Talaromyces > B. fulva. • The addition of preservatives reduced z-values from 8.9–10.1 °C to 6.9–6.8 °C. • Screw-capped tube and three neck round render higher D* values than other methods. • Talaromyces and Neosartorya are more heat sensitive to a drop in pH than Byssochlamys. • Meta-regression models are useful in thermal process design and shelf-life estimation. [ABSTRACT FROM AUTHOR]

• Prosopis pallida pods flour was tested as supplementary flour in breadmaking. • Mesquite flour (MF) increased the amount of fibre and unsaturated fatty acids. • Partially replacing wheat flour with MF did not produce harder crumbs. • MF in low ash content flour delays the loss in crumb elasticity during shelf life. • MF in low ash content flour slows down crumb hardening during shelf life. The objective of this study was to evaluate the effect of partially replacing two types of wheat flour (low ash content [type 55] and high ash content [type 65]) with Peruvian Prosopis pallida (mesquite) pod flour (0, 5, 10, 15%) on the nutritional quality and staling of composite breads. Mesquite flour (MF) enhanced the nutritional quality by increasing the fibre contents and unsaturated fatty acids of the bread. MF did not affect crumb hardness either when prepared with wheat flour type 65 (p = 0.374) or 55 (p = 0.122), but reduced crumb resilience (p < 0.001) and water activity (p = 0.003) in both wheat flour types. When blended with wheat flour type 55, increasing levels of MF delayed the dehydration (p < 0.001) and resilience loss rates. Likewise, the higher the MF level, the slower the crumb hardening of composite breads formulated with wheat flour type 55 (p = 0.028). Thus, MF did not only enhance the nutritional profile of composite breads, but could also retard staling as a supplement of wheat flour type 55. [ABSTRACT FROM AUTHOR]

The fate of Listeria monocytogenes during ripening of artisanal Minas semi-hard cheese, as influenced by cheese intrinsic properties and by autochthonous (naturally present) or intentionally-added anti-listerial lactic acid bacteria (LAB) was modeled. Selected LAB strains with anti-listerial capacity were added or not to raw or pasteurized milk to prepare 4 cheese treatments. Counts of LAB and L. monocytogenes , pH, temperature and water activity were determined throughout cheese ripening (22 days, 22±1ᵒC). Different approaches were adopted to model the effect of LAB on L. monocytogenes : an independent approach using the Huang primary model to describe LAB growth and the linear decay model to describe pathogen inactivation; the Huang-Cardinal [pH] model using the effect of pH variation in a dynamic tertiary approach; and the Jameson-effect with N max tot model which simultaneously describes L. monocytogenes and LAB fate. L. monocytogenes inactivation occurred in both treatments with added LAB and inactivation was faster in raw milk cheese (−0.0260 h−1) vs. pasteurized milk cheese (−0.0182 h−1), as estimated by the linear decay model. Better goodness-of-fit was achieved for the cheeses without added LAB when the Huang primary model was used. A faster and great pH decline was detected for cheeses with added LAB, and the Huang-Cardinal [pH] model predicted higher pathogen growth rate in cheese produced with raw milk, but greater L. monocytogenes final concentration in pasteurized milk cheese. The Jameson-effect model with N max tot predicted that LAB suppressed pathogen growth in all treatments, except in the treatment with pasteurized milk and no LAB addition. The Huang-Cardinal [pH] model was more accurate in modeling L. monocytogenes kinetics as a function of pH changes than was the Jameson-effect model with N max tot as a function of LAB inhibitory effect based on the goodness-of-fit measures. The Jameson-effect model may however be a better competition model since it can more easily represent L. monocytogenes growth and death. This study presents crucial kinetic data on L. monocytogenes behavior in the presence of competing microbiota in Minas semi-hard cheese under dynamic conditions. • Three different approaches were evaluated to predict L. monocytogenes behavior in semi-hard cheese. • All proposed models were capable of closely describing L. monocytogenes growth/death potential. • Huang-Cardinal [pH] present better fit quality than the Jameson-effect model. • The Huang-Cardinal model was not able to describe inactivation. • Addition of anti-listerial LAB results in a decrease in L. monocytogenes. [ABSTRACT FROM AUTHOR]

In cheese-making, a starter culture composed of adequately chosen lactic acid bacteria (LAB) may be suitable to ensure the rapid acidification of milk, improve textural and sensory characteristics, and avoid pathogen proliferation. In this work, 232 LAB isolates collected from artisanal goat's raw milk cheeses produced in Portugal were evaluated for their antimicrobial capacity (at 10 and 37°C), as well as their acidifying and proteolytic properties. Among the 232 isolates, at least 98% of those isolated in De Man-Rogosa-Sharpe (MRS) agar presented antagonism against Listeria monocytogenes, Salmonella Typhimurium, or Staphylococcus aureus, whereas less than 28.1% of M17-isolated LAB showed antagonism against these pathogens. M17-isolated LAB displayed better results than MRS ones in terms of acidifying capacity. As for the proteolytic assay, only 2 MRS isolates showed casein hydrolysis capacity. Principal component analyses and molecular characterization of a subset of selected isolates were conducted to identify those with promising capacities and to correlate the identified LAB genera and species with their antimicrobial, acidifying, and/or proteolytic properties. Lactococcus strains were associated with the highest acidifying capacity, whereas Leuconostoc and Lacticaseibacillus strains were more related to antimicrobial capacities. Leuconostoc mesenteroides, Lactococcus lactis, and Lacticaseibacillus paracasei were the predominant organisms found. The results of this work highlight various strains with pathogen inhibition capacity and suitable technological properties to be included in a customized starter culture. In future work, it is necessary to appropriately define the starter culture and implement it in the cheese-making process to evaluate if the in-vitro capacities are observable in a real food system. [ABSTRACT FROM AUTHOR]

An assessment was conducted on the level of inactivation of relevant pathogens that could be present in processed animal protein of porcine origin intended to feed poultry and aquaculture animals when methods 2 to 5 and method 7, as detailed in Regulation (EU) No 142/2011, are applied. Five approved scenarios were selected for method 7. Salmonella Senftenberg, Enterococcus faecalis, spores of Clostridium perfringens and parvoviruses were shortlisted as target indicators. Inactivation parameters for these indicators were extracted from extensive literature search and a recent EFSA scientific opinion. An adapted Bigelow model was fitted to retrieved data to estimate the probability that methods 2 to 5, in coincidental and consecutive modes, and the five scenarios of method 7 are able to achieve a 5 log10 and a 3 log10 reduction of bacterial indicators and parvoviruses, respectively. Spores of C. perfringens were the indicator with the lowest probability of achieving the target reduction by methods 2 to 5, in coincidental and consecutive mode, and by the five considered scenarios of method 7. An expert knowledge elicitation was conducted to estimate the certainty of achieving a 5 log10 reduction of spores of C. perfringens considering the results of the model and additional evidence. A 5 log10 reduction of C. perfringens spores was judged: 99–100% certain for methods 2 and 3 in coincidental mode; 98–100% certain for method 7 scenario 3; 80–99% certain for method 5 in coincidental mode; 66–100% certain for method 4 in coincidental mode and for method 7 scenarios 4 and 5; 25–75% certain for method 7 scenario 2; and 0–5% certain for method 7 scenario 1. Higher certainty is expected for methods 2 to 5 in consecutive mode compared to coincidental mode. [ABSTRACT FROM AUTHOR]

Cattle coming from feedlots to slaughter often harbor pathogenic E . coli that can contaminate final meat products. As a result, reducing pathogenic contamination during processing is a main priority. Unfortunately, food safety specialists face challenges when trying to determine optimal intervention strategies from published literature. Plant intervention literature results and methods vary significantly, making it difficult to implement interventions with any degree of certainty in their effectiveness. To create a more robust understanding of plant intervention effectiveness, a formal systematic literature review and meta-analysis was conducted on popular intervention methods. Effect size or intervention effectiveness was measured as raw log reduction, and modeled using study characteristics, such as intervention type, temperature of application, initial microbial concentration, etc. Least-squares means were calculated for intervention effectiveness separately on hide and on carcass surfaces. Heterogeneity between studies (I 2 ) was assessed and factors influencing intervention effectiveness were identified. Least-squares mean reductions (log CFU/cm 2 ) on carcass surfaces (n = 249) were 1.44 [95% CI: 0.73–2.15] for acetic acid, 2.07 [1.48–2.65] for lactic acid, 3.09 [2.46–3.73] for steam vacuum, and 1.90 [1.33–2.47] for water wash. On hide surfaces (n = 47), least-squares mean reductions were 2.21 [1.36–3.05] for acetic acid, 3.02 [2.16–3.88] for lactic acid, 3.66 [2.60–4.72] for sodium hydroxide, and 0.08 [− 0.94–1.11] for water wash. Meta-regressions showed that initial microbial concentrations and timing of extra water washes were the most important predictors of intervention effectiveness. Unexplained variation remained high in carcass, hide, and lactic acid meta-regressions, suggesting that other significant moderators are yet to be identified. The results will allow plant managers and risk assessors to evaluate plant interventions, variation, and factors more effectively. [ABSTRACT FROM AUTHOR]

Health concerns have led to a search for natural plant-based antimicrobials. Ellagic acid has been shown to have antimicrobial activity against foodborne pathogens. The objective of this study was to assess the effect of a high-ellagic acid commercial pomegranate on the heat resistance of Escherichia coli O104:H4 in ground chicken. A full 2 4 factorial design was used, consisting of temperature treatment with four levels (55.0, 57.5, 60.0, and 62.5 °C) and pomegranate with four levels (0.0, 1.0, 2.0, and 3.0 wt/wt. % containing 70% ellagic acid). Experiments were conducted twice, providing a total of 32 survival curves. A three-parameter Weibull primary model was used to describe survival kinetics. Secondary models were then developed to estimate the shape parameter β (i.e., curvature representing susceptibility of cells to stress), scale parameter γ (i.e., time to reach the first decimal reduction) and the 5.0-log lethality time t 5.0 (i.e., time to reach a 5.0-log reduction), all as polynomial functions of temperature and pomegranate powder concentration. The positive effect of pomegranate concentration on both β and γ demonstrated that the phenolic-rich pomegranate powder causes E. coli O104:H4 cells to become more susceptible to heat, increasing the steepness and concavity of the isothermal survival curves. It was estimated that the 5.0-log reduction time would reach a minimum at a pomegranate powder concentration of 1%, producing a 50% decrease in lethality time, in comparison to that without added pomegranate powder. Nonetheless, a mixed-effect omnibus regression further confirmed that the greatest difference in the thermal resistance of E. coli O104:H4 happened between tests with and without pomegranate powder. In fact, adding more than 1.0% pomegranate powder, at a constant temperature, resulted only in a marginal decrease in thermal resistance. Meat processors can use the model to design lethality treatments in order to achieve specific reductions of E. coli O104:H4 in ground chicken. [ABSTRACT FROM AUTHOR]

The aim of this study was to perform a meta-analysis of the effects of sanitizing treatments of fresh produce on Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes. From 55 primary studies found to report on such effects, 40 were selected based on specific criteria, leading to more than 1,000 data on mean log reductions of these three bacterial pathogens impairing the safety of fresh produce. Data were partitioned to build three meta-analytical models that could allow the assessment of differences in mean log reductions among pathogens, fresh produce, and sanitizers. Moderating variables assessed in the meta-analytical models included type of fresh produce, type of sanitizer, concentration, and treatment time and temperature. Further, a proposal was done to classify the sanitizers according to bactericidal efficacy by means of a meta-analytical dendrogram. The results indicated that both time and temperature significantly affected the mean log reductions of the sanitizing treatment (P< 0.0001). In general, sanitizer treatments led to lower mean log reductions when applied to leafy greens (for example, 0.68 log reductions [0.00 to 1.37] achieved in lettuce) compared to other, nonleafy vegetables (for example, 3.04 mean log reductions [2.32 to 3.76] obtained for carrots). Among the pathogens, E. coli O157:H7 was more resistant to ozone (1.6 mean log reductions), while L. monocytogenes and Salmonella presented high resistance to organic acids, such as citric acid, acetic acid, and lactic acid (_3.0 mean log reductions). With regard to the sanitizers, it has been found that slightly acidic electrolyzed water, acidified sodium chlorite, and the gaseous chlorine dioxide clustered together, indicating that they possessed the strongest bactericidal effect. The results reported seem to be an important achievement for advancing the global understanding of the effectiveness of sanitizers for microbial safety of fresh produce. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess the combined effects of temperature, pH, sodium chloride (NaCl), and sodium pyrophosphate (SPP) on the heat resistance of Escherichia coli O157:H7 in minced beef meat. A fractional factorial design consisted of four internal temperatures (55.0, 57.5, 60.0 and 62.5 °C), five concentrations of NaCl (0.0, 1.5, 3.0, 4.5 and 6.0 wt/wt.%) and SPP (0.0, 0.1, 0.15, 0.2 and 0.3 wt/wt.%), and five levels of pH (4.0, 5.0, 6.0, 7.0 and 8.0). The 38 variable combinations were replicated twice to provide a total of 76 survivor curves, which were modelled by a modified three-parameter Weibull function as primary model. The polynomial secondary models, developed to estimate the time to achieve a 3-log and a 5-log reduction, enabled the estimation of critical pH, NaCl and SPP concentrations, which are values at which the thermo-tolerance of E. coli O157:H7 reaches it maximum. The addition up to a certain critical concentration of NaCl (~ 2.7–4.7%) or SPP (~ 0.16%) acts independently to increase the heat resistance of E. coli O157:H7. Beyond such critical concentrations, the thermo-resistance of E. coli O157:H7 will progressively diminish. A similar pattern was found for pH with a critical value between 6.0 and 6.7, depending upon temperature and NaCl concentration. A mixed-effects omnibus regression model further revealed that the acidity of the matrix and NaCl concentration had a greater impact on the inactivation kinetics of E. coli O157:H7 in minced beef than SPP, and both are responsible for the concavity/convexity of the curves. When pH, SPP or NaCl concentration is far above or below from its critical value, the temperatures needed to reduce E. coli O157:H7 up to a certain log level are much lower than those required when any other environmental condition is at its critical value. Meat processors can use the model to design lethality treatments in order to achieve specific log reductions of E. coli O157:H7 in ready-to-eat beef products. [ABSTRACT FROM AUTHOR]

This study assessed the chemical profiles and bioactivities of the infusions, decoctions and hydroethanolic extracts of tarragon, basil and French lavender. The extracts were chemically characterised (HPLC-DAD-ESI/MS) and their bioactivities were evaluated in vitro. All extracts revealed antimicrobial, antifungal and antioxidant properties. French lavender extracts showed higher total phenolic content, regardless of the extraction method used, and antioxidant and antitumour capacities, but no anti-inflammatory action. All basil and two of the tarragon extracts revealed anti-inflammatory power. Thus, tarragon, basil and French lavender extracts may be considered for inclusion in foods, as preservatives or functional ingredients. Nonetheless, further studies must be conducted to evaluate the pharmacokinetic parameters of the bioactive compounds. • All extracts demonstrated antimicrobial, antifungal and antioxidant properties. • Basil and French lavender infusions showed the highest total phenolic content. • Tarragon decoction showed the highest anti-inflammatory capacity (IC 50 = 34.6 μg/mL). • All French lavender extracts were active against, at least, three tumour cell lines. • Hydroethanolic extracts showed undesirable toxicity against non-tumour hFOB cells. [ABSTRACT FROM AUTHOR]

In this study, the kinetic parameters of mesophilic, psychrotrophic and lactic acid bacteria in vacuum-packed beef at 1 °C and 4 °C were estimated from experimental growth curves produced by samples stored during 21 and 60 days, respectively. In a separate experiment, the survival of multidrug resistant (MDR) Salmonella enterica 0:4,5 at 1°C was also characterized. The shelf-life of vacuum-packed beef stored at 4 °C was estimated at 16.1 days (95% CI: 14.8 17.3 days), whereas at 1 °C it was longer than 21 days because the mesophiles count estimated towards the end of the experiment was 12.5 In CFU.g-1 (95% CI: 11.8 - 13.3 In CFU.g-1) which is lower than the shelf-life reference value. At 1 °C, inoculated Salmonella was reduced in 6.61 In CFU.g-1 (2.87 log CFU.g-1). These results demonstrated the importance of establishing in legislation, especially in Brazil, standard values of deteriorating microorganisms in beeffor maintaining product quality. [ABSTRACT FROM AUTHOR]

Abstract This study compares dynamic tertiary and competition models for L. monocytogenes growth as a function of intrinsic properties of a traditional Brazilian soft cheese and the inhibitory effect of lactic acid bacteria (LAB) during refrigerated storage. Cheeses were prepared from raw or pasteurized milk with or without the addition of selected LAB with known anti-listerial activity. Cheeses were analyzed for LAB and L. monocytogenes counts, pH and water activity (a w) throughout cold storage. Two approaches were used to describe the effect of LAB on L. monocytogenes : a Huang-Cardinal model that considers the effect of pH and a w variation in a dynamic kinetic analysis framework; and microbial competition models, including Lotka-Volterra and Jameson-effect variants, describing the simultaneous growth of L. monocytogenes and LAB. The Jameson-effect with γ and the Lotka-Volterra models produced models with statistically significant coefficients that characterized the inhibitory effect of selected LAB on L. monocytogenes in Minas fresh cheese. The Huang-Cardinal model [pH] outperformed both competition models. Taking a w change into account did not improve the fit quality of the Huang-Cardinal [pH] model. These models for Minas soft cheese should be valuable for future microbial risk assessments for this culturally important traditional cheese. Highlights • LAB with anti-listerial activity reduced the μ opt and Y max of L. monocytogenes. • Dynamic tertiary and competition models presented good fit quality. • Jameson-effect model with γ showed that LAB inhibited L. monocytogenes growth. • Lotka-Volterra model was significant for inhibition of L. monocytogenes. [ABSTRACT FROM AUTHOR]

Highlights • Chemical composition of black, red and white quinoa grains was explored. • Proteins and carbohydrates were main nutrients present. • Sucrose and oxalic acid were the major hydrophilic compounds. • γ-Tocopherol and linoleic acid were the main lipophilic compounds. • The three quinoa varieties presented very similar profiles. Abstract With the purpose of valuing the species Chenopodium quinoa Willd (quinoa), as well as encouraging the consumption of its grains, this study aimed at providing a detailed evaluation of the nutritional value and chemical composition of several quinoa grains of different colour varieties (black, red and white) from different origins. The results demonstrated an excellent composition, namely in the presence of many compounds of interest, such as organic acids, tocopherols and unsaturated fatty acids, as well as a very favourable nutritional profile, with carbohydrates and proteins being the prominent macronutrients. Regarding the different varieties, statistical analysis showed that there were no significant differences in studied parameters, with the exception of proteins, carbohydrates, oxalic acid, γ-tocopherol and total tocopherols content. Thus, this pseudocereal takes a position of nutritional excellence, compared to others cereals more commonly consumed, thereby representing a promising ingredient for many uses in the food industry. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess the combined effect of guar gum (GG) and water content (WC) on the rheological properties of batter, and the physicochemical and textural properties of bread. Batches of gluten-free bread used a base formulation of rice (50%), maize (30%) and quinoa flour (20%), with different levels of GG (2.5, 3.0 or 3.5%) and water (90, 100 or 110%) in a full factorial design. Higher GG doses (p < 0.001) tended to produce batters of lower stickiness, work of adhesion and cohesive strength; yet, of higher firmness, consistency, cohesiveness and viscosity index. These batters yielded loaves of lower (p < 0.001) specific volume and baking loss; and crumbs of lower (p < 0.001) aw, pH, mean cell area, void fraction, mean cell aspect ratio; and higher (p < 0.001) hardness, adhesiveness, springiness, cohesiveness, chewiness, resilience, mean cell density, cell size uniformity and mean cell compactness. The sticker and less consistent batters produced with higher WC rendered larger bread loaves of softer and more cohesive and springy/resilient crumbs with greater mean cell size and void fraction. Gluten-free loaves of good appearance in terms of higher specific volume, lower crumb hardness, higher crumb springiness, and open grain visual texture were obtained in formulations with 110% WC and GG doses between 2.5 and 3.0%. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the combined effect of xanthan gum (XG) on physicochemical, rheological and textural properties of gluten-free batter and bread. To prepare gluten-free batter, different levels of XG (1.5, 2.5 and 3.5%) and water (90, 100 and 110%) were added to a base formula of rice (50%), maize (30%) and quinoa flours (20%); and the batters were evaluated in a factorial design. Several properties on both batter (stickiness and back extrusion) and its corresponding bread (loaf specific volume, baking loss, water activity and pH, texture profile, mean cell area, mean cell density, cell size uniformity, void fraction, mean cell compactness and mean cell aspect ratio) were then evaluated. Higher XG doses (p < .001) tended to produce batters of lower stickiness, adhesion and cohesive-strength, yet, of higher firmness, consistency, cohesiveness and viscosity index. After baking, these loaves presented lower specific volume; lower crumb a w , pH, hardness, springiness, mean cell area and void fraction; and higher (p < .001) chewiness, resilience, mean cell density, cell size uniformity and mean cell compactness. The sticker and less consistent batters produced with higher WC rendered larger bread loaves of softer and more springy/resilient crumbs with greater mean cell size and void fraction. Gluten-free loaves of good appearance in terms of higher specific volume, lower crumb hardness, higher crumb springiness, and open grain visual texture were obtained in formulations with 110% WC and XG doses between 1.5 and 2.5%. [ABSTRACT FROM AUTHOR]

Artisanal raw milk cheeses are highly appreciated dairy products in Brazil and ensuring their microbiological safety has been a great need. This study reports the isolation and characterization of lactic acid bacteria (LAB) strains with anti-listerial activity, and their effects on Listeria monocytogenes during refrigerated shelf-life of soft Minas cheese and ripening of semi-hard Minas cheese. LAB strains (n = 891) isolated from Minas artisanal cheeses (n = 244) were assessed for anti-listerial activity by deferred antagonism assay at 37 °C and 7 °C. The treatments comprised the production of soft or semi-hard Minas cheeses using raw or pasteurized milk, and including the addition of selected LAB only [ Lactobacillus brevis 2-392, Lactobacillus plantarum 1-399 and 4 Enterococcus faecalis (1-37, 2-49, 2-388 and 1-400)], L. monocytogenes only, selected LAB co-inoculated with L. monocytogenes , or without any added cultures. At 37 °C, 48.1% of LAB isolates showed anti-listerial capacity and 77.5% maintained activity at 7 °C. Selected LAB strains presented a bacteriostatic effect on L. monocytogenes in soft cheese. L. monocytogenes was inactivated during the ripening of semi-hard cheeses by the mix of LAB added. Times to attain a 4 log-reduction of L. monocytogenes were 15 and 21 days for semi-hard cheeses produced with raw and pasteurized milk, respectively. LAB with anti-listerial activity isolated from artisanal Minas cheeses can comprise an additional barrier to L. monocytogenes growth during the refrigerated storage of soft cheese and help shorten the ripening period of semi-hard cheeses aged at ambient temperature. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop robust chemometric models for the routine determination of dietary constituents of quinoa ( Chenopodium quinoa Willd.) using Near-Infrared Transmission (NIT) spectroscopy. Spectra of quinoa grains of 77 cultivars were acquired while dietary constituents were determined by reference methods. Spectra were subjected to multiplicative scatter correction (MSC) or extended multiplicative signal correction (EMSC), and were (or not) treated by Savitzky-Golay (SG) filters. Latent variables were extracted by partial least squares regression (PLSR) or canonical powered partial least squares (CPPLS) algorithms, and the accuracy and predictability of all modelling strategies were compared. Smoothing the spectra improved the accuracy of the models for fat (root mean square error of cross-validation, RMSECV: 0.319–0.327%), ashes (RMSECV: 0.224–0.230%), and particularly for protein (RMSECV: 0.518–0.564%) and carbohydrates (RMSECV: 0.542–0.559%), while enhancing the prediction performance, particularly, for fat (root mean square error of prediction, RMSEP: 0.248–0.335%) and ashes (RMSEP: 0.137–0.191%). Although the highest predictability was achieved for ashes (SG-filtered EMSC/PLSR: bootstrapped 90% confidence interval for RMSEP: [0.376–0.512]) and carbohydrates (SG-filtered MSC/CPPLS: 90% CI RMSEP: [0.651–0.901]), precision was acceptable for protein (SG-filtered MSC/CPPLS: 90% CI RMSEP: [0.650–0.852]), fat (SG-filtered EMSC/CPPLS: 90% CI RMSEP: [0.478–0.654]) and moisture (non-filtered EMSC/PLSR: 90% CI RMSEP: [0.658–0.833]). [ABSTRACT FROM AUTHOR]

Currently, food industries need rapidly available information related to food production while most lab-based instrumentation techniques are often complicated and expensive for real-time application. Studies show that the measurement of rheological characteristics of dough is a relevant control variable for the proper formulation of ingredients and bread-making additives. It is in this context that this work aims to present an alternative method for real-time monitoring of the evolution of the dough behavior during processing with telemetry form. The dough behavior is monitored through the changes in the electrical properties of the motor as affected by the properties of the machine torque that makes the mixture. Results of this work showed that it is possible to record dough deformation during mixing in real time and also demonstrated how wireless technology can contribute to the quality control of a food processing system. [ABSTRACT FROM AUTHOR]

• The effect of the feeding system on meat of Gallega lambs was evaluated. • Rearing system does not affect chemical composition, except for the ash content. • Feeding system highly influenced individual volatile compounds and volatile families. • Benzyl alcohol and carbon disulfide were proposed as grass-diet biomarkers 1-butanone, 2-heptanone, and furan, 2-penthyl were concentrate-diet tracers. The chemical composition and volatile profile of the Longissimus thoracis et lumborum muscle of lambs reared in two distinct production systems (intensive and extensive) was evaluated. For this, sixty-six lambs for meat production of the autochthonous Gallega Iberian breed were raised with concentrate and grass in intensive (30 animals) and extensive (36 animals) system, respectively, until 4–4.5 months of age when they were slaughtered. Subsequently, Longissimus thoracis et lumborum muscles were excised for the determination of chemical composition (moisture, intramuscular fat, protein, and ash percentages) and volatile substances. The aftermaths obtained evidenced that moisture (75.90% and 75.68%), intramuscular fat (1.68% and 1.76%), and protein (20.62% and 20.97%) contents were not significantly (P > 0.05) affected by the production system. However, the extensively-fed lambs displayed a higher ash content (1.35% vs. 1.24%). Additionally, the total volatile content was also not significantly (P > 0.05) influenced by feeding system. Despite this, the total content of hydrocarbons, acids, aldehydes, ketones, esters, ethers, furans, sulfur compounds, and others was significantly (P < 0.05) affected by diet, being the alcohol family the only group not influenced (P > 0.05) by the production system (1321.3 vs. 1211.3 AU × 104/g fresh muscle). Specifically, intensively-fed lambs showed significantly higher amounts for all volatile families apart from ketones (2215 vs. 2826 AU × 104/g fresh muscle) and sulfur compounds (22.7 vs. 123.7 AU × 104/g fresh muscle). In addition, benzyl alcohol and carbon disulfide were proposed as appropriate biomarkers for grass diets, while 1-butanone, 2-heptanone, and furan, 2-penthyl were indicated as suitable tracers for concentrate-based diets. [ABSTRACT FROM AUTHOR]

• Lamb meat quality depends on the combined effect breed × production system. • BEDM and Gallega reared under extensive conditions had high amounts of n-3 PUFA. • Lambs reared under extensive system had the highest tocopherol and cholesterol levels. • Lambs reared under extensive system had the best n-6/n-3 ratio and high SFA content. • The production system and diet had great influence in meat quality. This study aimed to compare lamb meat composition from five Iberian breeds raised in their typical rearing systems and to reveal trends in compositional meat attributes due to breed or production system. The meat quality of 153 animals was analysed. The combined effect of breed × production system produced significant differences in lamb meat quality. Meat from the extensively-reared Bordaleira-de-Entre-Douro-e-Minho (BEDM) and Gallega breeds had elevated amounts of n-3 PUFAs, tocopherol content and favourable n-6/n-3 ratio. Meat from lambs grown under extensive and semi-extensive systems presented higher content of conjugated linoleic acid than the two breeds reared intensively. The meat of commercial breed (INRA401) was characterised by higher content of protein and MUFAs and lower atherogenic potential than the breeds reared in extensive and semi-extensive systems. Principal component analysis demonstrated that meat from extensively raised lambs was associated to higher SFA, CLA, α-tocopherol, n-3, atherogenic index and cholesterol content, but lower intramuscular fat and retinol content, MUFA and n-6/n-3. [ABSTRACT FROM AUTHOR]

• Phenolic composition of black, red and white quinoa grains was evaluated. • Quercetin and kaempferol derivatives were present in all quinoa varieties. • None of the quinoa varieties showed toxicity in hepatotoxocity assay. • All hydroethanolic extracts possessed antibacterial and antifungal activity. The ingestion of bioactive compounds has revealed health benefits, namely in the prevention and/or treatment of several diseases. This work aims to characterize the phenolic profile of three colour varieties of Chenopodium quinoa Willd. grains (black, red and white), and also evaluate their cytotoxic and antimicrobial activity. All varieties revealed the presence of phenolic compounds, namely, quercetin and kaempferol derivatives. In this study, quinoa grains did not reveal any anti-proliferative capacity in tumour cell lines, and, as expected, they were devoid of any toxicity. All of the analysed extracts possessed antibacterial and antifungal activities (inhibitory and bactericidal/fungicidal) against the microbial strains considered, exhibiting promising values of minimum bactericidal concentrations (mean MBC 0.153–0.916 mg/mL) and minimum fungicidal concentrations (mean MFC 0.211–0.884 mg/mL). Quinoa varieties represent a good source of bioactive compounds, interfering beneficially in the organism, specifically as antimicrobial agents. Thus, these extracts could be used in the development of bioactive ingredients. [ABSTRACT FROM AUTHOR]

• Cardinal values can be estimated by meta-analysing literature growth data. • The meta-regression models built provide an insight on sources of variability. • The cardinal values obtained can be used as reference values for risk assessments. Since Listeria monocytogenes has a high case-fatality rate, substantial research has been devoted to estimate its growth rate under different conditions of temperature, pH and water activity (a w). In this study, published findings on L. monocytogenes growth in broth were extracted and unified by constructing meta-regression models based on cardinal models for (i) temperature (CM[T]), (ii) temperature and pH (CM[T][pH]), and (iii) temperature, pH and a w (CM[T][pH][a w ]). After assessing all the sources retrieved between 1988 until 2017, forty-nine primary studies were considered appropriate for inclusion. Apart from the modelling variables, study characteristics such as: type of broth (BHI, TSB, TPB), reading method (colony-forming-units, CFU; or binary-dilution optical density methods, OD), inoculum concentration and strain serotype, were also extracted. Meta-regressions based on CM[T] and CM[T][pH] were fitted on subsets of the 2009 growth rate measures and revealed that type of broth and reading method significantly modulated the cardinal parameter estimates. In the most parsimonious CM[T][pH][a w ] meta-regression model, whereby the variability due to type of broth was extracted in a nested random-effects structure, the optimum growth rate μ opt of L. monocytogenes was found to be lower when measured as CFU (0.947 log CFU/h; SE = 0.094 log CFU/h) than when measured as OD (1.289 log CFU/h; SE = 0.092 log CFU/h). Such a model produced the following cardinal estimates: T min = -1.273 °C (SE = 0.179 °C), T opt = 37.26 °C (SE = 0.688 °C), T max = 45.12 °C (SE = 0.013 °C), pH min = 4.303 (SE = 0.014), pH opt = 7.085 (SE = 0.080), pH max = 9.483 (SE = 0.080), a w min = 0.894 (SE = 0.002) and a w opt = 0.995 (SE = 0.001). Integrating the outcomes from numerous L. monocytogenes growth experiments, this meta-analysis has estimated pooled cardinal parameters that can be used as reference values in quantitative risk assessment studies. [ABSTRACT FROM AUTHOR]