Influence of reduced levels or suppression of sodium nitrite on the outgrowth and toxinogenesis of psychrotrophic Clostridium botulinum Group II type B in cooked ham

Facile detection of botulinum neurotoxin using LSPR nanosensor based on Langmuir-Blodgett films of gold nanoparticles

In this exploratory study, Langmuir-Blodgett (LB) films of gold nanoparticles (Au NPs) were utilized for the first time to detect botulinum neurotoxin (BoNT) based on localized surface plasmon resonance (LSPR), acting as biosensors. Monolayers of Au NPs were initially transferred onto a transparent polymer substrate using the LB technique. This substrate was then used as the base material for subsequent depositions of capping ligands, and eventually, the BoNT at different concentrations. Upon each deposition, LSPR signals were recorded employing UV-Vis spectroscopy. As a result, it was demonstrated that the LB films transferred at a surface pressure of 35 mN m-1 were the optimal choice, capable of detecting BoNT at a concentration as low as 1 pg ml-1. Furthermore, it was discovered that the formation of Au NP clusters reduced the sensing capacity of the LB films. This sensor offers advantages such as easy fabrication and a quick detection process that utilizes visible light.

Effects of sodium nitrite reduction, removal or replacement on cured and cooked meat for microbiological growth, food safety, colon ecosystem, and colorectal carcinogenesis in Fischer 344 rats

Epidemiological and experimental evidence indicated that processed meat consumption is associated with colorectal cancer risks. Several studies suggest the involvement of nitrite or nitrate additives via N-nitroso-compound formation (NOCs). Compared to the reference level (120 mg/kg of ham), sodium nitrite removal and reduction (90 mg/kg) similarly decreased preneoplastic lesions in F344 rats, but only reduction had an inhibitory effect on Listeria monocytogenes growth comparable to that obtained using the reference nitrite level and an effective lipid peroxidation control. Among the three nitrite salt alternatives tested, none of them led to a significant gain when compared to the reference level: vegetable stock, due to nitrate presence, was very similar to this reference nitrite level, yeast extract induced a strong luminal peroxidation and no decrease in preneoplastic lesions in rats despite the absence of NOCs, and polyphenol rich extract induced the clearest downward trend on preneoplastic lesions in rats but the concomitant presence of nitrosyl iron in feces. Except the vegetable stock, other alternatives were less efficient than sodium nitrite in reducing L. monocytogenes growth.

Reduction of carcinogens in fermented fish (pla-ra and pla-som) by heating

Background and Aim

The risk factors for cholangiocarcinoma (CCA) are opisthorchiasis and the intake of a combination of nitroso compounds through the consumption of traditionally fermented fish, which is very popular in areas where liver flukes are endemic. The incidence of CCA remains high because this cultural habit of rural people has been altered. Therefore, decreasing nitrate and nitrite concentrations in fermented fish are an alternative approach to reducing the risk of CCA. Thus, this study aimed to reduce nitrate and nitrite concentrations in fermented foods by heating and investigated its effect on CCA development in a hamster model.

Materials and Methods

We used Association of Official Analytical Chemists method 973.31 to measure the nitrate and nitrite concentrations in both fermented fish (pla-ra [PR]) and pickled fish (pla-som [PS]) before and after boiling for 5 and 30 min, respectively. The same samples were fed to Opisthorchis viverrini (OV)-infected or -uninfected hamsters for 3 months. Thereafter, the hamsters' liver and blood were collected for analysis.

Results

The levels of nitrates and nitrites in PS and PR significantly decreased following boiling for 5 and 30 min. The OV-PR and OV-PS groups showed dramatically increased numbers of inflammatory cells, fibrosis surrounding the bile duct, and focal fibrotic areas. However, after boiling the fermented dishes for 5 and 30 min, the extent of inflammatory cell infiltration and intensity of fibrosis in these groups were decreased.

Conclusion

Our findings suggest that boiling reduces nitrate and nitrite toxicity in fermented dishes, as evidenced by reduced hepatic inflammation. However, regardless of heating, kidney tissues are adversely affected when fermented meals are consumed daily.

Challenge tests reveal limited outgrowth of proteolytic Clostridium botulinum during the production of nitrate- and nitrite-free fermented sausages

Nitrate and nitrite salts perform a versatile role in fermented meats, including the inhibition of food pathogens (in particular proteolytic group I Clostridium botulinum). Despite the increasing interest in clean-label products, little is known about the behaviour of this pathogen in response to the removal of chemical preservatives from fermented meat formulations. Therefore, challenge tests with a cocktail of nontoxigenic group I C. botulinum strains were performed to produce nitrate/nitrite-free fermented sausages under different acidification conditions and starter culture formulations, including the use of an anticlostridial Mammaliicoccus sciuri strain. Results showed limited outgrowth of C. botulinum, even in the absence of acidification. The anticlostridial starter culture did not lead to an additional inhibitory effect. The selective plating procedure adopted within this study proofed robust to follow germination and growth of C. botulinum, inhibiting common fermentative meat microbiota. The challenge tests constitute a suitable tool to assess the behaviour of this food pathogen within fermented meats upon nitrate- and nitrite omission.

Impact of environmental conditions and gut microbiota on the in vitro germination and growth of Clostridioides difficile

Clostridioides difficile is a spore-forming anaerobic Gram-positive bacterium responsible for a broad spectrum of intestinal symptoms and healthcare-associated diarrhoea. The hypothesis of this work was that different in vitro conditions, notably pH and human faecal microbiota composition, impact the germination and/or the growth of C. difficile. This study aimed to correlate growth kinetics of the bacterium with these two physiochemical parameters by using a static in vitro model. To better understand the initial gut colonisation, several growth curve assays were carried out to monitor the behaviour of the spores and vegetative forms of C. difficile strain 078 under different conditions mimicking the gut environment. When the faeces were added, no spore germination or growth was observed, but C. difficile spores germinated in vitro when the pH was maintained between 6.6 and 6.9 for four different faeces donors. The evolution of microbiota studied by 16S rDNA profiling showed high proportions of Enterobacteriaceae and E. coli/Shigella when C. difficile grew, regardless of the inoculated faeces. This model helped us to understand that the germination and growth of C. difficile are strongly pH dependent, and further research is needed to evaluate the potential impact of the gut microbiota composition on C. difficile.

Bell felcinin viral patojenitesi ve tedavi olarak botulinum toksin tip A kullanımı

Bell'in felci, kraniyal sinir VII'nin iltihaplanmasının ortak adıdır. Kendine özgü genikulat ganglion iltihabı idiyopatiktir ve hemifasiyal felce neden olur. Bu felçten muzdarip olan hastaların semptomları 3 hafta ile 3 ay arasında kaybolabilir. Yüz felci devam eden bazı hastalar için botulinum toksin tip A etkili bir tedavi olabilir. Kas felcinin şiddetine göre botoksun yanı sıra ameliyat, steroid ve antiviral tedavi gibi farklı tedaviler sunulabilir. Bu derleme makalesinin amacı, viral patojenlerin fasiyal sinir iltihabının aktivasyonu ile olası ilişkisine ve Bell felçli hastaların tedavi olarak botoks tip-A'dan nasıl yararlanabileceğine dalmaktır.

Nitrite-Free Implications on Consumer Acceptance and the Behavior of Pathogens in Cured Pork Loins

Cured pork loins are valued products due to their particular sensory characteristics. These products are usually prepared with nitrite to guarantee adequate color and pathogen control. The use of nitrite in meat products has been criticized due to its potential contribution to carcinogenic N-nitroso-compound formation. The present work aimed to evaluate the effect of eliminating nitrite from the manufacturing of cured loins made with wine- and water-based marinades on the color evaluation of consumers and on the behavior of Clostridium sporogenes, Listeria monocytogenes, and Salmonella. The use of nitrite in processing cured loins resulted in a color considered adequate by more than 50% of the consumers. When nitrite was not used, the color was described mainly as weak. The hedonic evaluation of cured loins did not reflect the color evaluation. The samples with a weak and an adequate color had similar hedonic evaluations. The present work did not allow us to infer the potential interest in injecting S. xylosus into meat to prepare cured loins. The use of nitrite did not affect the survival of Cl. sporogenes, L. monocytogenes, or Salmonella. The reduction in the aw was the primary determinant influencing pathogen survival. The production of nitrite-free cured loins seems possible once the control of pathogens can be achieved. However, the product will have a weaker color. Consumers appreciate sensory aspects other than color, which, combined with the positive impact of the “additive-free” claim, can support the possibility of producing cured loins without nitrite.

Review: Pork quality attributes from farm to fork. Part II. Processed pork products

Pork is often consumed in a very wide variety of products, processed from integral cuts or minced meat using different conservation methods (curing, smoking, cooking, drying, fermenting). Quality of pork products results from a combination between the properties of the raw material and the processing conditions to elaborate the final products. The influence of primary production factors, slaughtering and carcass processing on the quality of fresh pork has been reviewed (part 1), considering quality as an integrative combination of various attributes: commercial, organoleptic, nutritional, technological, convenience, and societal image, the latter denotes cultural, ethical (including animal welfare) and environment dimensions related to the way pork is produced, processed, and its geographical origin. This review (part 2) focuses on the influence of primary production factors and processing techniques on the quality of two important and economically significant processed pork products issued from contrasting processing techniques: cooked ham and dry-cured ham. As with fresh pork, many factors influence the quality of processed products, and one factor can affect several attributes. Moreover, in the case of processed products, numerous factors in both animal production and processing steps interact to determine their quality attributes. The quality of cooked ham depends on the properties of the raw material (in particular pH, colour, water holding capacity, presence of destructured meat defect, etc.) which are determined by pig husbandry practices (especially the genotype), pre-, postslaughter and processing conditions including the composition of curing mixture (ingredients, additives), salting, mixing and heat treatment. Processing techniques of cooked ham aim at homogenising the product quality within a given quality category (e.g. 'standard' or 'superior') or brand. Therefore, the variability of raw material is problematic for the cooked ham processing industry, which generally seeks uniformity and homogeneity of fresh hams. Likewise, pig husbandry conditions exert even greater impact on dry-cured ham quality. Indeed, the properties of raw material (including weight of fresh ham, fat thickness, pH, intramuscular fat and antioxidants content, fatty acid profile, etc.) that result from combined effects of primary production factors (genotype, feeding, production system, etc.) interact with processing conditions (salting, drying, ripening conditions and duration, etc.) to elaborate the quality attributes of the final products. Synergies can be sought between the primary production factors and processing techniques leading to specific organoleptic characteristics (texture, taste, aroma, flavour, etc.) that can be valued by quality labels. Quality of products is thus built along the whole chain from farm to fork.

Predictive model for growth of Clostridium botulinum from spores during cooling of cooked ground chicken

Cooking temperature of poultry meat is typically inadequate to inactivate the heat resistant spores of Clostridium botulinum. The purpose of this study is to develop a predictive model for C. botulinum during cooling of cooked ground chicken. Cooked chicken was inoculated with a cocktail of five strains of proteolytic C. botulinum type A and five strains of proteolytic C. botulinum type B to yield a final spore concentration of approximately 2 log CFU/g. The growth of C. botulinum was determined at constant temperatures from 10 to 46 °C. Dynamic temperature experiments were performed with continued cooling from 54.4 to 4.4 °C or 7.2 °C in mono- or bi-phasic cooling profiles, respectively. The Baranyi primary model was used to fit growth data and the modified Ratkowsky secondary model was used to fit growth rates with respect to temperature. The primary models fitted the growth data well (R² values ranging from 0.811 to 0.988). The R² and root mean square error (RMSE) of the modified Ratkowsky secondary model were 0.95 and 0.06, respectively. Out of 11 prediction error values calculated in this study, ten were within the limit of acceptable prediction zone (-1.0 to 0.5), indicating a good fit of the model. The predictive model will assist institutional food service operations in determining the safety of cooked ground chicken subjected to different cooling periods.

Cacao Pod Husk Flour as an Ingredient for Reformulating Frankfurters: Effects on Quality Properties

The cocoa pod husk is considered a source of dietary fiber with a high content of water-soluble pectins, bioactive compounds which should be viewed as a by-product with the potential to be incorporated into food. This study aimed to investigate the effect of adding different cocoa pod husk flour (CPHF) levels as a starch replacement for reformulating frankfurters. Results showed that the addition of 1.5 and 3.0% pod husk proportionally increased the frankfurter’s fiber content by 0.49 ± 0.08 and 0.96 ± 0.19 g/100 g, which is acceptable for a product that does not contain fiber. Textural properties and sensory characteristics were affected when substituting the starch with CPHF, either totally or partially, although these samples had higher water content, hardness, and adhesiveness while springiness decreased. Non-adverse effects of nitrite on polyphenolic compounds content were evidenced in samples enriched with CPHF. The incorporation of CPHF did not significantly affect the color parameters (ΔE < 3). Finally, the panelists indicated a sensation of the unsalted sausage, suggesting that CPHF may have natural mucoadhesion properties. In conclusion, in formulated meat products such as sausages, plant co-products such as cacao pod husks could be a valid new ingredient to improve technological parameters, functional characteristics, and stability.

New Insights into the Chemical Reactivity of Dry-Cured Fermented Sausages: Focus on Nitrosation, Nitrosylation and Oxidation

Nitrite and nitrate are added to cured meat for their bacteriological, technological and sensorial properties. However, they are suspected to be involved in the formation of nitroso compounds (NOCs), such as potentially mutagenic nitrosamines, nitrosylheme and nitrosothiols. Controlling the sanitary and sensorial qualities of cured meat products by reducing these additives requires elucidating the mechanisms involved in the formation of NOCs. To this end, we studied the dose-response relationship of added sodium nitrite and/or sodium nitrate (0/0, 80/80, 0/200, and 120/120 ppm) on the formation of NOCs in dry cured fermented sausages. The results showed a basal heme iron nitrosylation in the absence of NaNO2/NaNO3 due to starter cultures. This reaction was promoted by the addition of NaNO2/NaNO3 in the other conditions. Reducing the dose to 80/80 ppm still limits lipid oxidation without the formation of non-volatile nitrosamines. Conversely, the addition of NO2/NO3 slightly increases protein oxidation through higher carbonyl content. The use of 80/80 ppm could be a means of reducing these additives in dry-cured fermented meat products.

Clean Label Meat Technology: Pre-Converted Nitrite as a Natural Curing

Clean labeling is emerging as an important issue in the food industry, particularly for meat products that contain many food additives. Among synthetic additives, nitrite is the most important additive in the meat processing industry and is related to the development of cured color and flavor, inhibition of oxidation, and control of microbial growth in processed meat products. As an alternative to synthetic nitrite, pre-converted nitrite from natural microorganisms has been investigated, and the applications of pre-converted nitrite have been reported. Natural nitrate sources mainly include fruits and vegetables with high nitrate content. Celery juice or powder form have been used widely in various studies. Many types of commercial starter cultures have been developed. S. carnosus is used as a critical nitrate reducing microorganism and lactic acid bacteria or other Staphylococcus species also were used. Pre-converted nitrite has also been compared with synthetic nitrite and studies have been aimed at improving utilization by exploiting the strengths (positive consumer attitude and decreased residual nitrite content) and limiting the weaknesses (remained carcinogenic risk) of pre-converted nitrite. Moreover, as concerns regarding the use of synthetic nitrites increased, research was conducted to meet consumer demands for the use of natural nitrite from raw materials. In this report, we review and discuss various studies in which synthetic nitrite was replaced with natural materials and evaluate pre-converted nitrite technology as a natural curing approach from a clean label perspective in the manufacturing of processed meat products.