A culture-based assessment of the microbiota of conventional and free-range chicken meat from Irish processing facilities.

Chicken meat is the most popularly consumed meat worldwide, with free-range and ethically produced meat a growing market among consumers. However, poultry is frequently contaminated with spoilage microbes and zoonotic pathogens which impact the shelf-life and safety of the raw product, constituting a health risk to consumers. The free-range broiler microbiota is subject to various influences during rearing such as direct exposure to the external environment and wildlife which are not experienced during conventional rearing practices. Using culture-based microbiology approaches, this study aimed to determine whether there is a detectable difference in the microbiota from conventional and free-range broilers from selected Irish processing plants. This was done through analysis of the microbiological status of bone-in chicken thighs over the duration of the meat shelf-life. It was found that the shelf-life of these products was 10 days from arrival in the laboratory, with no statistically significant difference (P > 0.05) evident between free-range and conventionally raised chicken meat. A significant difference, however, was established in the presence of pathogenesis-associated genera in different meat processors. These results reinforce past findings which indicate that the processing environment and storage during shelf-life are key determinants of the microflora of chicken products reaching the consumer.

Survive and thrive: Control mechanisms that facilitate bacterial adaptation to survive manufacturing-related stress.

The control of bacterial contaminants on chicken meat is a key area of interest in the broiler industry. Microbes that pose a significant food safety risk on chicken include Campylobacter spp., Salmonella enterica, Listeria monocytogenes and Escherichia coli. In addition, microbes including Pseudomonas spp., Brochothrix thermosphacta and Lactic Acid Bacteria must be controlled to ensure product quality and maintain shelf-life. Poultry meat processing challenges including cold and chemical exposure are employed to control the microbiota of the end-product, as well as to maintain environment hygiene. Exposure to these stresses can also induce adaptive shifts in the transcriptome and proteome of foodborne bacteria. This review will explore the complex interactions at play in the poultry processing environment and explain how bacteria exposed to such stresses behave in this environmental niche through the production of heat and cold-shock proteins, the expression of efflux pumps, sporulation, and the formation of mono- and mixed-species biofilms within the production environment.

The changing microbiome of poultry meat; from farm to fridge.

Chickens play host to a diverse community of microorganisms which constitute the microflora of the live bird. Factors such as diet, genetics and immune system activity affect this complex population within the bird, while external influences including weather and exposure to other animals alter the development of the microbiome. Bacteria from these settings including Campylobacter and Salmonella play an important role in the quality and safety of end-products from these birds. Further steps, including washing and chilling, within the production cycle aim to control the proliferation of these microbes as well as those which cause product spoilage. These steps impose specific selective pressures upon the microflora of the meat product. Within the next decade, it is forecast that poultry meat, particularly chicken will become the most consumed meat globally. However, as poultry meat is a frequently cited reservoir of zoonotic disease, understanding the development of its microflora is key to controlling the proliferation of important spoilage and pathogenic bacterial groups present on the bird. Whilst several excellent reviews exist detailing the microbiome of poultry during primary production, others focus on fate of important poultry pathogens such as Campylobacter and Salmonella spp. At farm and retail level, and yet others describe the evolution of spoilage microbes during spoilage. This review seeks to provide the poultry industry and research scientists unfamiliar with food technology process with a holistic overview of the key changes to the microflora of broiler chickens at each stage of the production and retail cycle.

On farm interventions to minimise Campylobacter spp. contamination in chicken.

1. This review explores current and proposed on-farm interventions and assess the potential of these interventions against Campylobacter spp. 2. Interventions such as vaccination, feed/water-additives and, most importantly, consistent biosecurity, exhibit potential for the effective control of this pathogen and its dissemination within the food chain. 3. Due to the extensive diversity in the Campylobacter spp. genome and surface-expressed proteins, vaccination of poultry is not yet regarded as a completely effective strategy. 4. The acidification of drinking water through the addition of organic acids has been reported to decrease the risk of Campylobacter spp. colonisation in broiler flocks. Whilst this treatment alone will not completely protect birds, use of water acidification in combination with in-feed measures to further reduce the level of Campylobacter spp. colonisation in poultry may be an option meriting further exploration. 5. The use of varied types of feed supplements to reduce the intestinal population and shedding rate of Campylobacter spp. in poultry is an area of growing interest in the poultry industry. Such supplements include pro - and pre-biotics, organic acids, bacteriocins and bacteriophage, which may be added to feed and water. 6. From the literature, it is clear that a distinct, albeit not unexpected, difference between the performance of in-feed interventions exists when examined in vitro compared to those determined in in vivo studies. It is much more likely that pooling some of the discussed approaches in the in-feed tool kit will provide an answer. 7. Whilst on-farm biosecurity is essential to maintain a healthy flock and reduce disease transmission, even the most stringent biosecurity measures may not have sufficient, consistent and predictable effects in controlling Campylobacter spp. Furthermore, the combination of varied dietary approaches and improved biosecurity measures may synergistically improve control.

Applications of nonthermal plasma technology on safety and quality of dried food ingredients.

Cold plasma technology is an efficient, environmental-friendly, economic and noninvasive technology; and in recent years these advantages placed this novel technology at the centre of diverse studies for food industry applications. Dried food ingredients including spices, herbs, powders and seeds are an important part of the human diet; and the growing demands of consumers for higher quality and safe food products have led to increased research into alternative decontamination methods. Numerous studies have investigated the effect of nonthermal plasma on dried food ingredients for food safety and quality purposes. This review provides critical review on potential of cold plasma for disinfection of dried food surfaces (spices, herbs and seeds), improvement of functional and rheological properties of dried ingredients (powders, proteins and starches). The review further highlights the benefits of plasma treatment for enhancement of seeds performance and germination yield which could be applied in agricultural sector in near future. Different studies applying plasma technology for control of pathogens and spoilage micro-organisms and modification of food quality and germination of dried food products followed by benefits and current challenges are presented. However, more systemic research needs to be addressed for successful adoption of this technology in food industry.

Genetic variation in taste perception: does it have a role in healthy eating?

Taste is often cited as the factor of greatest significance in food choice, and has been described as the body's 'nutritional gatekeeper'. Variation in taste receptor genes can give rise to differential perception of sweet, umami and bitter tastes, whereas less is known about the genetics of sour and salty taste. Over twenty-five bitter taste receptor genes exist, of which TAS2R38 is one of the most studied. This gene is broadly tuned to the perception of the bitter-tasting thiourea compounds, which are found in brassica vegetables and other foods with purported health benefits, such as green tea and soya. Variations in this gene contribute to three thiourea taster groups of people: supertasters, medium tasters and nontasters. Differences in taster status have been linked to body weight, alcoholism, preferences for sugar and fat levels in food and fruit and vegetable preferences. However, genetic predispositions to food preferences may be outweighed by environmental influences, and few studies have examined both. The Tastebuddies study aimed at taking a holistic approach, examining both genetic and environmental factors in children and adults. Taster status, age and gender were the most significant influences in food preferences, whereas genotype was less important. Taster perception was associated with BMI in women; nontasters had a higher mean BMI than medium tasters or supertasters. Nutrient intakes were influenced by both phenotype and genotype for the whole group, and in women, the AVI variation of the TAS2R38 gene was associated with a nutrient intake pattern indicative of healthy eating.

Resistance of Cronobacter sakazakii in reconstituted powdered infant formula during ultrasound at controlled temperatures: a quantitative approach on microbial responses.

Many of the documented outbreaks of Cronobacter sakazakii have been linked to infant formula. The aims of this work are to monitor the inactivation kinetics of C.sakazakii NCTC 08155 and ATCC 11467 and to determine quantitatively the effectiveness of ultrasonic treatments as an alternative to heat processing of reconstituted infant milk formula before feeding of infants at highest risk. Inactivation studies of C. sakazakii inoculated in reconstituted infant formula were performed at the combined conditions of temperature, i.e., 25 degrees C, 35 degrees C, 50 degrees C and amplitude, i.e., 24.4, 30.5, 42.7, 54.9, 61 microm and the kinetics were described by a range of inactivation models. The dependency of the specific inactivation rate with respect to the product of temperature and amplitude was described by a modified Bigelow type model. Ultrasound combined with temperature was efficient to reduce significantly the microbial levels of C. sakazakii. C. sakazakii strain NCTC 08155 was at the same range of temperature and amplitude resistance as strain ATCC 11467. Application of ultrasound is an alternative process for the production of safe reconstituted infant formula. This study contributes on the quantitative assessment of the resistance of C. sakazakii.

PEF based hurdle strategy to control Pichia fermentans, Listeria innocua and Escherichia coli k12 in orange juice.

The combination of pulsed electric fields (PEF) and bacteriocins in a hurdle approach has been reported to enhance microbial inactivation. This study investigates the preservation of orange juice using PEF in combination with nisin (2.5 ppm), natamycin (10 ppm), benzoic acid (BA; 100 ppm), or lactic acid, (LA; 500 ppm). Pichia fermentans, a spoilage yeast frequently isolated from orange juice, Escherichia coli k12 or Listeria innocua were inoculated into sterile orange juice (OJ) with, and without, added preservatives. The antimicrobial activity over time was evaluated relative to an untreated control. The effect of PEF treatment (40 kV/cm, 100 micros; max temperature 56 degrees C) was assessed on its own, and in combination with each antimicrobial. The acidic environment of OJ inactivated E. coli k12 (1.5log reduction) and L. innocua (0.7log reduction) slightly but had no effect on P. fermentans. PEF caused a significant decrease (P<0.05) in the viability of P. fermentans, L. innocua and E. coli k12 achieving reductions of 4.8, 3.7 and 6.3log respectively. Nisin combined with PEF inactivated L. innocua and E. coli k12 in a synergistic manner resulting in a total reduction to 5.6 and 7.9log respectively. A similar synergy was shown between LA and PEF in the inactivation of L. innocua and P. fermentans (6.1 and 7.8log reduction), but not E. coli k12. The BA-PEF combination caused an additive inactivation of P. fermentans, whereas the natamycin-PEF combination against P. fermentans was not significantly different to the effect caused by PEF alone. This study shows that combining PEF with the chosen preservatives, at levels lower than those in current use, can provide greater than 5log reductions of E. coli k12, L. innocua and P. fermentans in OJ. These PEF-bio-preservative combination hurdles could provide the beverage industry with effective non-thermal alternatives to prevent microbial spoilage, and improve the safety of fruit juice.

Modelling of yeast inactivation in sonicated tomato juice.

Power ultrasound is recognised as a potential non thermal technique to inactivate microorganisms pertinent to fruit juices. In this study, the effect of sonication on the resistance of yeast (Pichia fermentans) in tomato juice was investigated. Tomato juice samples were sonicated at amplitude levels ranging from 24.4 to 61.0mum at a constant frequency of 20kHz for different treatment times (2 to 10min) and pulse durations of 5s on and 5s off. Significant reductions (p<0.05) were observed at higher amplitudes and processing times. Yeast inactivation was found to follow the Weibull model with a high regression coefficient (R(2)>0.98) and low RMSE (<0.51). The desired 5 log reductions (D(5) value) and shape factors were found to correlate exponentially with amplitude level. Results presented in this study show that sonication alone is an effective process to achieve the desired level of yeast inactivation in tomato juice.

Pre-inoculation enrichment procedure enhances the performance of bacteriocinogenic Lactococcus lactis meat starter culture.

Sodium nitrite and sodium chloride may inhibit growth and bacteriocinogenesis of protective starter cultures. To reduce sensitivity of a lacticin 3147-producing starter culture to nitrite, prior to production of salami, Lactococcus lactis DPC 4275 was placed in a number of pre-inoculation treatments, containing (a) 1% glucose, (b) 2.5 ppm manganese (Mn), (c) 250 ppm magnesium (Mg), (d) 2.5 ppm manganese + 250 ppm magnesium (Mn + Mg), and held at ambient temperature for 30 min and 4 degrees C for 2 h. The growth, pH reduction, and bacteriocin production was monitored in beaker sausage over a period of 10 days at 28 degrees C, corresponding to typical salami production time, and compared to untreated starter culture. The effect of 1% tryptone and inoculum level on growth and bacteriocin production was also determined. Challenge tests were performed using Listeria innocua DPC 1770 and Staphylococcus aureus MMPR3 as target strains. All treatments gave a significantly higher (P < 0.05) initial starter level than the untreated starter. Beaker sausage inoculated with either low (10(7)) or high (10(9)) levels of starter culture, treated with Mn + Mg reached significantly (P < 0.05) higher levels by day 10 than other treatments. Trends indicate that Mn + Mg also gave best pH reduction in sausage containing the low-level starter culture, sausage and significantly lower (P < 0.05) values for sausage produced with higher inoculum. Bacteriocin production was also higher in starter culture treated with Mn, or glucose. Pre-treatment with Mg gave a 2-fold increase in bacteriocin, the addition of Mn augmenting this increase further. The incorporation of tryptone gave no additional effect. In beaker sausage, both L. innocua and S. aureus populations showed significant reductions (P < 0.05) in the presence of the bacteriocinogenic strain compared to a non-bacteriocinogenic control strain.

Development of bioactive food packaging materials using immobilised bacteriocins lacticin 3147 and nisaplin.

Immobilisation of the bacteriocins nisin and lacticin 3147 to packaging materials was investigated. Stability of both cellulose-based bioactive inserts and anti-microbial polyethylene/polyamide pouches was examined over time. Anti-microbial activity against the indicator strain Lactococcus lactis subsp. lactis HP, in addition to Listeria innocua DPC 1770 and Staphylococcus aureus MMPR3 was observed for all bacteriocin-adsorbed materials. Activity retention of the inserts showed an initial decrease in the first week of storage but remained stable for the remaining 3 months of the trial. However, adsorption of lacticin 3147 to plastic film was unsuccessful, nisin bound well and the resulting film maintained its activity for 3-month period, both at room temperature and under refrigeration. When applied to food systems, the anti-microbial packaging reduced the population of lactic acid bacteria in sliced cheese and ham stored in modified atmosphere packaging (MAP) at refrigeration temperatures, thus extending the shelf life. Nisin-adsorbed bioactive inserts reduced levels of Listeria innocua by > or = 2 log units in both products, and Staphylococcus aureus by approximately 1.5 log units in cheese, and approximately 2.8 log units in ham. Similar reductions were observed in cheese vacuum-packaged in nisin-adsorbed pouches.

Continuous production of lacticin 3147 and nisin using cells immobilized in calcium alginate.

Bacteriocinogenic strains, Lactococcus lactis subsp. lactis DPC 3147 and L. lactis DPC 496, producing lacticin 3147 and nisin, respectively, were immobilized in double-layered calcium alginate beads. These beads were inoculated into MRS broth at a ratio of 1:4 and continuously fermented for 180 h. Free cells were used to compare the effect of immobilization on bacteriocin production. After equilibrium was reached, a flow rate of 580 ml h(-1) was used in the immobilized cell (IC), and 240 ml h(-1) in free-cell (FC) bioreactors. Outgrowth from beads was observed after 18 h. Bacteriocin production peaked at 5120 AU ml(-1) in both IC and FC bioreactors. However, FC production declined after 80 h to 160 AU ml(-1) at the end of the fermentation. Results of this study indicate that immobilization offers the possibility of a more stable and long-term means of producing lacticin 3147 in laboratory media than with free cells.

An effective lacticin biopreservative in fresh pork sausage.

Lacticin 3147 is a novel heat-stable bacteriocin, produced by Lactococcus lactis DPC 3147, that exhibits a broad-range inhibition spectrum similar to nisin. In this study, the effect of lacticin 3147 and nisin on the shelf life of fresh pork sausage and their ability to control pathogens (Clostridium perfringens DSM 756, Salmonella Kentucky AT1) and nonpathogenic Listeria innocua DPC 1770 was investigated. The following preservative regimens were evaluated, both in broth and sausage systems: (i) 450 ppm of sodium metabisulphite; (ii) 500 IU g(-1) or ml(-1) of nisin, (iii) 2500 arbitary units (AU) g(-1) or ml(-1) of lacticin 3147; (iv) 2% sodium lactate and 500 IU of nisin; (v) 2% sodium citrate and 500 IU g(-1) or ml(-1) of nisin; (vi) 2% sodium lactate and 2500 AU g(-1) or ml(-1) of lacticin 3147, (vii) 2% sodium citrate and 2500 AU g(-1) or ml(-1) of lacticin 3147, (viii) 2% sodium lactate, and (ix) 2% sodium citrate. There was no significant difference in the activity of nisin and lacticin 3147 against any of the target strains used, both bacteriocins performing significantly better than sodium metabisulfite against gram-positive strains in broth systems. Trends indicate that the combination of organic acids with either bacteriocin enhanced its activity against Salmonella Kentucky and L. innocua and was particularly effective in the inhibition of C. perfringens in fresh pork sausage. In addition, lacticin 3147 combined with either sodium citrate or sodium lactate maintained significantly lower (P < 0.05) total aerobic plate counts for the duration of the trials and may function as an alternative to sodium metabisulfite in the preservation of fresh pork sausage.

Determination of the influence of organic acids and nisin on shelf-life and microbiological safety aspects of fresh pork sausage.

The effect of replacing sulphur dioxide with organic acids and nisin to reduce the microbial counts in fresh pork sausage was examined. The potential of sodium citrate or sodium lactate, used singly or in combination with nisin, was also assessed in sausage inoculated with Staphylococcus aureus MMPR 3 and Salmonella kentucky AT 1. The results indicate that a combination of sodium lactate and nisin wa particularly effective in reducing total bacterial counts in this food product. It also appears that this combination provides an increased protection against common pathogenic contaminants of fresh pork sausage, i.e. Staph. aureus and Salmonella species.

The camouflaged home health clinical nurse specialist.

Home health clinical nurse specialists are camouflaged. The contributions that they make to the home health specialty are stymied and often are invisible to individuals outside of the specialty. Their role is less developed and is less implemented than in other nursing specialties. There are impediments to role development, including difficulties in defining the clinical base of the specialty, the independence and consultative nature of all home health nursing practice despite differences in educational backgrounds or levels of practice, and regulatory and reimbursement restrictions. Responsibilities and qualifications of the home health clinical nurse specialist are presented. The author suggests that these nurses review and sign Medicare Plan of Treatment insurance forms (instead of physicians), because most of home healthcare is nursing care dealing with functional abilities rather than medical care.