Refined liquid smoke: a potential antilisterial additive to cold-smoked sockeye salmon (Oncorhynchus nerka)

Using liquid smoke to control infestations of the ham mite, Tyrophagus putrescentiae, on dry-cured hams during aging

Eight treatments of edible coatings and nets including liquid smoke (SP and 24P) and xanthan gum (XG) were used to evaluate their effectiveness at controlling mite growth on dry-cured hams. Mite growth was controlled (P < 0.05) in both coating and netting treatments of 1% SP + 1% XG. Increasing SP concentration from 1% to 2% in the SP only treatments without XG did not control mite growth (P > 0.05) in the coating but controlled mite growth (P < 0.05) when infused in the nets. Both coating and netting treatments with 2% 24P + 1% XG controlled mite growth (P < 0.05), and ham cubes with 1% and 2% 24P in infused nets had mite numbers of 4.6 and 9.4, respectively. SP did not impact the sensory attributes of the ham. Results indicate that liquid smoke can potentially be added in coatings or ham nets to control mites and used in an integrated pest management program for dry-cured hams.

Mild processing of seafood-A review

Recent years have shown a tremendous increase in consumer demands for healthy, natural, high-quality convenience foods, especially within the fish and seafood sector. Traditional processing technologies such as drying or extensive heating can cause deterioration of nutrients and sensory quality uncompilable with these demands. This has led to development of many novel processing technologies, which include several mild technologies. The present review highlights the potential of mild thermal, and nonthermal physical, and chemical technologies, either used alone or in combination, to obtain safe seafood products with good shelf life and preference among consumers. Moreover, applications and limitations are discussed to provide a clear view of the potential for future development and applications. Some of the reviewed technologies, or combinations thereof, have shown great potential for non-seafood products, yet data are missing for fish and seafood in general. The present paper visualizes these knowledge gaps and the potential for new technology developments in the seafood sector. Among identified gaps, the combination of mild heating (e.g., sous vide or microwave) with more novel technologies such as pulsed electric field, pulsed light, soluble gas stabilization, cold plasma, or Ohmic heat must be highlighted. However, before industrial applications are available, more research is needed.

Effect of different types of smoking materials on the flavor, heterocyclic aromatic amines, and sensory property of smoked chicken drumsticks

This study investigated the effect of different types of smoking materials on the flavor, heterocyclic aromatic amine (HAA) content, and sensory attributes of smoked chicken drumsticks. All smoked samples showed lower pH and L*-value and higher a*-value and b*-value than the control sample (P < 0.05), but no significant differences in water content and water activity (P > 0.05). The samples smoked with sucrose combined with pear-tree woodchips (SP) or green tea leaves (ST) had higher overall acceptability than other samples (P < 0.05). Smoking increased the total HAA content, and the ST sample exhibited the highest total HAA content (P < 0.05). A total of 54 volatile compounds was identified. Overall, SP and ST are suitable for smoked chicken considering the sensory properties, while S and SA are proper for smoked chicken considering the minimization of HAAs, which may provide a theory basis for the production of smoked chicken.

Prosopis Plant Chemical Composition and Pharmacological Attributes: Targeting Clinical Studies from Preclinical Evidence

Members of the Prosopis genus are native to America, Africa and Asia, and have long been used in traditional medicine. The Prosopis species most commonly used for medicinal purposes are P. africana, P. alba, P. cineraria, P. farcta, P. glandulosa, P. juliflora, P. nigra, P. ruscifolia and P. spicigera, which are highly effective in asthma, birth/postpartum pains, callouses, conjunctivitis, diabetes, diarrhea, expectorant, fever, flu, lactation, liver infection, malaria, otitis, pains, pediculosis, rheumatism, scabies, skin inflammations, spasm, stomach ache, bladder and pancreas stone removal. Flour, syrup, and beverages from Prosopis pods have also been potentially used for foods and food supplement formulation in many regions of the world. In addition, various in vitro and in vivo studies have revealed interesting antiplasmodial, antipyretic, anti-inflammatory, antimicrobial, anticancer, antidiabetic and wound healing effects. The phytochemical composition of Prosopis plants, namely their content of C-glycosyl flavones (such as schaftoside, isoschaftoside, vicenin II, vitexin and isovitexin) has been increasingly correlated with the observed biological effects. Thus, given the literature reports, Prosopis plants have positive impact on the human diet and general health. In this sense, the present review provides an in-depth overview of the literature data regarding Prosopis plants' chemical composition, pharmacological and food applications, covering from pre-clinical data to upcoming clinical studies.

Effects of gamma radiation combined with cinnamon oil on qualities of smoked salmon slices inoculated with Shewanella putrefaciens

Smoked salmon slices inoculated with Shewanella putrefaciens were untreated (CK) or treated with 2 kGy gamma radiation (G), 1% (v/v) cinnamon oil (C), or the combination of them (G+C), and then packaged and stored at 4°C for 10 days. Microbiological and physiochemical analyses were then carried out. All treatments showed a better effect on inhibiting the increase in total viable counts, total volatile basic nitrogen, and thiobarbituric acid-reactive substances than CK, especially the treatment of G+C. In addition, the combination treatment also showed a best effect on retarding the reduction in polyunsaturated fatty acids of salmon samples in all treatments. These results indicated that treatments of gamma radiation and cinnamon oil on salmon samples, especially the combination treatment, can be used to maintain the quality of smoked salmon slices.

Selection of Surrogate Bacteria for Use in Food Safety Challenge Studies: A Review

Nonpathogenic surrogate bacteria are prevalently used in a variety of food challenge studies in place of foodborne pathogens such as Listeria monocytogenes, Salmonella, Escherichia coli O157:H7, and Clostridium botulinum because of safety and sanitary concerns. Surrogate bacteria should have growth characteristics and/or inactivation kinetics similar to those of target pathogens under given conditions in challenge studies. It is of great importance to carefully select and validate potential surrogate bacteria when verifying microbial inactivation processes. A validated surrogate responds similar to the targeted pathogen when tested for inactivation kinetics, growth parameters, or survivability under given conditions in agreement with appropriate statistical analyses. However, a considerable number of food studies involving putative surrogate bacteria lack convincing validation sources or adequate validation processes. Most of the validation information for surrogates in these studies is anecdotal and has been collected from previous publications but may not be sufficient for given conditions in the study at hand. This review is limited to an overview of select studies and discussion of the general criteria and approaches for selecting potential surrogate bacteria under given conditions. The review also includes a list of documented bacterial pathogen surrogates and their corresponding food products and treatments to provide guidance for future studies.

Rice hull smoke extract protects mice against a Salmonella lipopolysaccharide-induced endotoxemia

Endotoxemia (sepsis, septic shock) is an inflammatory, virulent disease that results mainly from infection by Gram-negative bacteria. The present study investigates the inhibitory effects of a rice hull smoke extract (RHSE) against murine endotoxemia induced by Salmonella lipopolysaccharide and d-galactosamine (LPS/GalN). Pretreatment of the mice with RHSE via dietary administration for 2 weeks resulted in the suppression (in %) of LPS/GalN-induced catalase by 70.7, superoxide dismutase (SOD) by 54.6, and transaminase (GOT/GPT) liver enzymes by 40.6/62.5, the amelioration of necrotic liver lesions, and the reduction of tumor necrosis factor-α (TNF-α) by 61.1 and nitrite serum level by 83.4, as well as myeloperoxidase (MPO) enzyme associated with necrotic injury of the lung and kidney by 65.7 and 63.3, respectively. The RHSE also extended the lifespan of the toxemic mice. The results using inflammation biomarkers and from the lifespan studies suggest that the RHSE can protect mice against LPS/GalN-induced liver, lung, and kidney injuries and inflammation by blocking oxidative stress and TNF-α production, thereby increasing the survival of the toxic-shock-induced mice. These beneficial effects and previous studies on the antimicrobial effects against Salmonella Typhimurium in culture and in mice suggest that the smoke extract also has the potential to serve as a new multifunctional resource in human food and animal feeds. Possible mechanisms of the beneficial effects at the cellular and molecular levels and suggested food uses are discussed.

Temperature effects on the antimicrobial efficacy of condensed smoke and lauric arginate against Listeria and Salmonella

Condensed smoke or liquid smoke (LS) and lauric arginate (LAE) are antimicrobials used in food preservation. They have demonstrated abilities to reduce or inhibit pathogenic and spoilage organisms. Few studies, however, have reported on the effectiveness of LS or LAE over the range of temperatures typically encountered in food marketing channels. Therefore, the effects of temperature on the antimicrobial properties of two commercial LS fractions, an LS derived from pecan shells, and LAE against two common foodborne pathogens, Listeria and Salmonella, were investigated. The MICs of the three LS samples and LAE were measured at 4, 10, and 37°C for Listeria monocytogenes strains 2045 (Scott A, serotype 4b) and 10403S (serotype 1/2a) and two strains of Listeria innocua, a well-established surrogate, and at 10, 25, and 37°C for Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Heidelberg. The MICs for LS against Listeria ranged from 3 to 48% (vol/vol), with higher MICs seen with lower temperatures. The MICs for LS on Salmonella ranged from 3 to 24%. Values for LAE ranged between 0.004 and 0.07% for both pathogens, and like LS, higher MICs were always associated with lower incubation temperatures. Understanding how storage temperature affects the efficacy of antimicrobials is an important factor that can contribute to lowering the hurdles of use levels and costs of antimicrobials and ultimately improve food safety for the consumer.

Listeria monocytogenes in Vacuum-Packed Smoked Fish Products: Occurrence, Routes of Contamination, and Potential Intervention Measures

The occurrence of Listeria monocytogenes in ready-to-eat (RTE) fish products is well documented and represents an important food safety concern. Contamination of this pathogen in vacuum-packed (VP) smoked fish products at levels greater than the RTE food limit (100 CFU/g) has been traced to factors such as poor sanitary practices, contaminated processing environments, and temperature abuse during prolonged storage in retail outlets. Intervention technologies including physical, biological, and chemical techniques have been studied to control transmission of L. monocytogenes to these products. High-pressure processing, irradiation, and pulsed UV-light treatment have shown promising results. Potential antilisterial effects of some sanitizers and combined chemical preservatives have also been demonstrated. Moreover, the concept of biopreservation, use of bioactive packaging, and a combination of different intervention technologies, as in the hurdle concept, are also under consideration. In this review, the prevalence, routes of contamination, and potential intervention technologies to control transmission of L. monocytogenes in VP smoked fish products are discussed.

Functionality of liquid smoke as an all-natural antimicrobial in food preservation

The smoking of foods, especially meats, has been used as a preservation technique for centuries. Today, smoking methods often involve the use of wood smoke condensates, commonly known as liquid smoke. Liquid smoke is produced by condensing wood smoke created by the pyrolysis of sawdust or wood chips followed by removal of the carcinogenic polyaromatic hydrocarbons. The main products of wood pyrolysis are phenols, carbonyls and organic acids which are responsible for the flavor, color and antimicrobial properties of liquid smoke. Several common food-borne pathogens such as Listeria monocytogenes, Salmonella, pathogenic Escherichia coli and Staphylococcus have shown sensitivity to liquid smoke in vitro and in food systems. Therefore liquid smoke has potential for use as an all-natural antimicrobial in commercial applications where smoke flavor is desired. This review will cover the application and effectiveness of liquid smoke and fractions of liquid smoke as an all-natural food preservative. This review will be valuable for the industrial and research communities in the food science and technology areas.