Epidemiological studies suggest that fish consumption may be a protective factor against the development of prostate cancer. We investigated the association between prostate cancer risk and fresh and preserved fish consumption among participants of a population-based case-control study (1,534 cases, 1,607 controls). Fish intake was measured using a dietary questionnaire that collected both frequency of consumption of a given portion size. Logistic regression analysis demonstrated an inverse association between preserved fish and prostate cancer risk for all levels of consumption, but reductions only reached statistical significance for the category of 1 to 3 servings of preserved fish per month (odds ratio = 0.78, confidence interval = 0.64-0.95). Consumption of any fat or energy from preserved fish was also associated with reduced risk. There was no suggestion of reduced prostate cancer risk with consumption of fresh and canned fish. Our results suggest that consumption of preserved fish may reduce the risk of developing prostate cancer.
The natural microflora of cold-smoked fish at the end of shelf-life are lactic acid bacteria (LAB). Some of these display a capacity to inhibit spoilage as well as several strains of pathogenic micro-organisms, e.g. Listeria monocytogenes which is isolated frequently from cold-smoked salmon (CSS). Eight batches of sliced vacuum-packed CSS from Norway, Scotland and Spain were collected at retail. Packs were stored at 5 degrees C and examined for chemical and microbiological characteristics, at purchase date and at expiration date. pH, water activity and salt content were similar to available data on lightly preserved fish products. There was a consistent pattern in the development of the microflora on CSS; the initial level of LAB was low on freshly produced CSS (10(2) cfu g(-1)); however, storage in vacuum packaging at refrigeration temperature was elective for LAB. At the end of the stated shelf-life these micro-organisms, represented mainly by Lactobacillus spp., attained ca.10(7) cfu g(-1) while Enterobacteriaceae counts were consistently lower (10(5) cfu g(-1)), which indicates the ability of LAB to grow and compete with few carbohydrates available and in the presence of moderate salt concentrations. L. monocytogenes was not found in any sample. Forty-one percent of LAB strains isolated exhibited inhibitory capacity against Listeria innocua, in a plate assay. A majority of the inhibitory effects were non-bacteriocinogenic, but nevertheless were very competitive cultures which may provide an additional hurdle for improved preservation by natural means.
The objective of this study was to evaluate (eO), a biological time temperature integrator (TTI) as a quality and safety indicator for ground beef packed under modified atmosphere and spiced cooked chicken slices packed under modified atmosphere. Storage trials and challenge tests were thus performed on several batches of the studied food to monitor and model the behavior of Listeria monocytogenes, Salmonella, Staphylococcus aureus and the indigenous food flora. Then, two different prototypes of the TTI (eO) were set and manufactured according to the studied products shelf lives. The TTI evolution with time at static and dynamic temperatures was monitored and modeled. Finally, exposure assessment models were set and used under several realistic storage profiles to assess the distributions of the concentration of the indigenous food flora and the distributions of the increase in the pathogens populations obtained at the end of the product shelf life or at the end point of the TTI, taking into account the TTIs batch variability. Results showed that in case of poor storage conditions, TTI can reduce the consumer exposure to altered or hazardous foods.
The potential use of the commercial biocontrol products Serenade (Bacillus subtilis QST-713) and Trichodex (Trichoderma harzianum Rifai strain T39) to inhibit the postharvest pathogenic molds Penicillium crustosum and Mucor circinelloides was investigated. Both products exhibited antagonistic activity in vitro against the pathogens, reducing their growth at different levels. In addition, epiphytic yeasts isolated from peaches were identified as Candida maltosa, Pichia fermentans, and Pichia kluyveri by PCR-restriction fragment length polymorphism of internal transcribed spacer regions and screened for antagonistic activity against the same molds. The efficacy of biocontrol in vitro was dependent on the concentration of the yeast cells. Optimal yeast concentrations were above 10(7) CFU ml(-1). However, C. maltosa and P. fermentans were more effective than P. kluyveri in inhibiting molds. The exclusion of antifungal metabolite production and direct competition for nutrients or space with the pathogens was proposed as the mechanism of biocontrol. Application of biocontrol agents directly on artificially wounded peach fruits significantly reduced the incidence of mold rot during storage at 20 degrees C.
The growth of Penicillium spp. on the surface of meat-based dry fermented sausages provides them with a protective effect against some undesirable microorganisms. Penicillium also acts as an antioxidant, minimizes the risk of excessive drying, and it is responsible for flavor development due to the decomposition of proteins, free fatty acids and lactic acid. With the aim of developing starter cultures, important physiological properties such as growth and proteolytic and lipolytic activities were evaluated on 13 mold strains belonging to the genera Penicillium. These strains were isolated from Argentinean dry fermented meat sausages named "salami". The selection was based on color, mycellium appearance and growth characteristics. The most important factors of the drying process of salami, such as temperature (14 and 25 degrees C), water activity (aw) (0.90, 0.95 and 1.00) and presence of 2.5% sodium chloride (NaCl), were analyzed. Although all strains analyzed were able to grow under the different conditions evaluated, they showed different growth velocity (K = mm/day) in response to temperature, aw and presence of NaCl in the media. All strains showed both proteolytic and lipolytic activities under the studied factors of the drying process. Nevertheless, differences in inter-species and even intra-species were found. The addition of NaCl gave a stimulant effect to the proteolytic activity at 25 degrees C, but the response at 14 degrees C was variable. The same variability was observed in the presence of salt, both at 25 and 14 degrees C, when the lipolytic activity was assayed. According to our results, detailed assays of the physiological capacities of indigenous strains proposed as starter cultures are required.
New fresh-cut fruit and vegetable products are being developed worldwide. Nutrition educators' perceptions of these products were studied.
Professional dietitians in Nova Scotia were asked to complete a questionnaire on their use of fresh-cut produce. The questionnaire also elicited their attitudes and perceptions about the convenience, taste/quality, nutrition/health benefits, cost, and safety of fresh-cut fruit and vegetables.
Sixty-three percent of respondents reported eating five to six servings of fruit and vegetables a day. This group most frequently consumed fresh-cut fruit as snacks or dessert, and vegetables in stir-fry dishes or salads or cooked with meals. In general, fresh-cut fruit and vegetables were perceived as convenient, safe, and nutritious. While approximately 50% of participants felt fresh-cut produce did not differ in taste from whole fresh produce, almost the same number considered whole fresh produce superior in taste.
Dietitians have a generally positive perception of fresh-cut products; however, there is uncertainty about the nutritional value, cost/benefit, and use of the products. Dietitians require more information on the nutrient value of these products and on suggested alternative uses. Attention should be paid to developing fresh-cut products that have good sensory quality.
The native microflora of lettuce cultivated in mulch and on bare soil and its evolution during storage at optimal condition were evaluated. Inner, mid, and outer leaves of the lettuce heads were analyzed separately and the evolution of the microbial populations were fitted to Gompertz and logistic models. The cultivation method (bare soil and mulch) introduced differences in the initial counts, evolution, and tolerance to refrigeration temperatures for some of the microbial populations under study. Most microbial populations from mulch lettuce presented a decline or little growth under refrigerated storage. However, populations from bare soil lettuce presented some growth phase during storage. Lactic acid bacteria from bare soil lettuce presented significant growth after 8 d of storage while LAB from mulch grown lettuce did not. Concurrently with the LAB growth, there was a decline in the coliform counts in bare soil grown lettuce. At the end of storage, the inner and mid leaves of mulch lettuce presented lower counts of psychrotrophic bacteria, LAB, and yeast and molds.
Lamb chops inoculated with 2.23-2.83 log cfu/g of E. coli O157:H7 strain NCTC 12900 were packed in air (AP), vacuum (VP), and two modified atmospheres (MAP) consisting of 100% CO2 and a commercial mixture of 35% CO2/35% O2/30% N2. All samples (initial total counts
The food industry, including the meat industry, is currently looking for natural preservatives to prevent the growth of harmful microbes in foods. The potential of plant-derived antimicrobial extracts to increase the shelf life and to delay the microbiological spoilage of marinated broiler chicken cuts in modified atmosphere packages during cold storage was investigated in this study. We evaluated the impact of aqueous ethanolic extracts of Finnish sea buckthorn berries and lingonberries and supercritical CO2-extracted herbal extracts from an antimicrobial blend and oregano leaves on the shelf life of broiler meat. The commercial antimicrobial blend extract and the oregano extract inhibited the growth of lactic acid bacteria (LAB) and Brochothrix thermosphacta in the marinated samples. The antimicrobial blend extract also reduced the growth of psychrotrophic aerobic bacteria, whereas the sea buckthorn and lingonberry extracts did not. Only minor antimicrobial activity against Enterobacteriaceae by all the extracts was observed. Plate count analysis, denaturing gradient gel electrophoresis, and quantitative real-time PCR indicated that LAB, which are the major spoilage group in marinated modified atmosphere-packaged poultry products, were not significantly affected by the berry extracts studied. During this shelf-life study, LAB isolates of Lactobacillus and Leuconostoc were identified in the marinated samples. Antimicrobial blends and oregano leaf extracts can act as antimicrobial agents in marinade blends, although tailoring of the dose is needed because of their strong taste. Further studies for exploiting synergistic effects of plant extracts could contribute to the development of potential and more effective antimicrobial blends. Studies are needed in meat matrices and in product applications to demonstrate the efficacy of these compounds.
Australian Food Safety Centre of Excellence, Tasmanian Institute of Agricultural Research, School of Agricultural Science, University of Tasmania, Private Bag 54, Hobart 7001, Tasmania, Australia. email@example.com
Two commercially available organic acid salts, potassium lactate (PURASAL HiPure P) and a potassium lactate-sodium diacetate blend (PURASAL Opti. Form PD 4), were assessed as potential inhibitors of Listeria monocytogenes growth in modified atmosphere packaged (MAP) sliced ham in challenge studies. The influence of the initial inoculation level of L. monocytogenes (10(1) or 10(3) CFU g(-1)) and storage temperature (4 or 8 degrees C) was also examined. The addition of either organic acid salt to MAP sliced ham strongly inhibited the growth of L. monocytogenes during the normal shelf life of the product under ideal refrigeration conditions (4 degrees C) and even under abusive temperature conditions (i.e., 8 degrees C). During the challenge studies and in the absence of either organic acid salt, L. monocytogenes numbers increased by 1000-fold after 20 days at 8 degrees C and 10-fold after 42 days at 4 degrees C. Both organic acid salt treatments were found to be listeriostatic rather than listericidal. The addition of either organic acid salt to the MAP ham also reduced the growth of indigenous microflora, i.e., aerobic microflora and lactic acid bacteria. The influence of these compounds on the risk of listeriosis in relation to product shelf life is discussed.