Viable Mycobacterium avium ssp. paratuberculosis isolated from calf milk replacer

When advising farmers on how to control Johne's disease in an infected herd, one of the main recommendations is to avoid feeding waste milk to calves and instead feed calf milk replacer (CMR). This advice is based on the assumption that CMR is free of viable Mycobacterium avium ssp. paratuberculosis (MAP) cells, an assumption that has not previously been challenged. We tested commercial CMR products (n = 83) obtained from dairy farms around the United States by the peptide-mediated magnetic separation (PMS)-phage assay, PMS followed by liquid culture (PMS-culture), and direct IS900 quantitative PCR (qPCR). Conventional microbiological analyses for total mesophilic bacterial counts, coliforms, Salmonella, coagulase-negative staphylococci, streptococci, nonhemolytic Corynebacterium spp., and Bacillus spp. were also performed to assess the overall microbiological quality of the CMR. Twenty-six (31.3%) of the 83 CMR samples showed evidence of the presence of MAP. Seventeen (20.5%) tested positive for viable MAP by the PMS-phage assay, with plaque counts ranging from 6 to 1,212 pfu/50 mL of reconstituted CMR (average 248.5 pfu/50 mL). Twelve (14.5%) CMR samples tested positive for viable MAP by PMS-culture; isolates from all 12 of these samples were subsequently confirmed by whole-genome sequencing to be different cattle strains of MAP. Seven (8.4%) CMR samples tested positive for MAP DNA by IS900 qPCR. Four CMR samples tested positive by both PMS-based tests and 5 CMR samples tested positive by IS900 qPCR plus one or other of the PMS-based tests, but only one CMR sample tested positive by all 3 MAP detection tests applied. All conventional microbiology results were within current standards for whole milk powders. A significant association existed between higher total bacterial counts and presence of viable MAP indicated by either of the PMS-based assays. This represents the first published report of the isolation of viable MAP from CMR. Our findings raise concerns about the potential ability of MAP to survive manufacture of dried milk-based products.     

Growth performance,carcass and meat quality of the Celta pig crossbred with Duroc and Landrance genotypes

The Celta pig is a native breed adapted to the north of Spain and extensive production system. The objective was to study the effects of sex and crossbreeding on carcass characteristics and meat quality. Samples were taken from longissimus dorsi muscle of 52 pigs of three different groups [Celta pure breed (C), Celta crossed with Landrace (C × L) and Celta crossed with Duroc (C × D)].     

Changes in bioactive compounds and antioxidant activity during convective drying of murta (Ugni molinae T.) berries

Murta (Ugni molinae T.) berries were air‐dried at five temperatures (40, 50, 60, 70 and 80 °C), and the changes in β‐carotene, phenolic acids, total phenolic and flavonoid contents and antioxidant capacities (DPPH and ORAC) were investigated. The berries showed a high content of β‐carotene, which decreased during drying temperature between 40 °C and 80 °C. Free and bound phenolic acids were also determined, showing gallic acid to be the prevalent phenolic acid. Total phenolic and flavonoid contents in the dried berries showed a higher decrease at lower temperature due to longer drying time. The radical‐scavenging activity also showed higher antioxidant activity at higher drying temperatures (70–80 °C) than at lower drying temperatures (40–50 °C). Total phenolic content (TPC) and flavonoids showed good correlation with antioxidant capacity. Murta berries proved to be an excellent source of antioxidants and bioactive compounds and are therefore a potential ingredient for new functional food products.     

Effect of varying oxygen concentrations on the shelf-life of fresh pork sausages packaged in modified atmosphere

A total of 105 fresh pork sausages were packaged in atmospheres varying in oxygen concentration, using the following mixtures (%O₂/%CO₂/%N₂): 0/20/80, 0/20/80 + O₂ scavenger, 20/20/60, 40/20/40, 60/20/20, and 80/20/0. In addition, two batches were subjected to vacuum packaging or over-wrap with O₂-permeable film. They were stored for 20 days at 2 ± 1 °C in the dark. Values of pH, CIE L*, a* and b* color parameters, surface metmyoglobin percentage, TBA-reactive substances, psychrotroph aerobe bacterial numbers and sensory discoloration and off-odor were assessed throughout storage. Packaging in the absence of O₂, either under vacuum or in atmosphere with O₂ scavenger, led to extension of shelf-life in terms of both color and odor stability due to low oxidation rates. Increase of O₂ caused a significant enhancement of oxidation, decrease of shelf-life due to discoloration and off-odor development. The highest O₂ concentration gave rise to a significant color improvement, though only for a limited period of 8 days.     

Quantification of Se-Methylselenocysteine and Its γ-Glutamyl Derivative from Naturally Se-Enriched Green Bean (Phaseolus vulgaris vulgaris) After HPLC-ESI-TOF-MS and Orbitrap MS n -Based Identification

Orthogonal liquid chromatographic (ion exchange, reversed phase, and ion pairing) and mass spectrometric [electrospray ionization (ESI)-TOF-MS, ESI-Orbitrap MS, and inductively coupled plasma mass spectrometry (ICP-MS)] methods were addressed to identify and quantify selenium species from a naturally Se-enriched green bean (Phaseolus vulgaris vulgaris) sample after proteolytic digestion. While selenomethionine (10.1 mg/kg as Se) and selenate (9.5 mg/kg as Se) could be quantified in a straightforward way by anion exchange LC-ICP-MS technique, a multistep purification protocol was required to identify Se-methylselenocysteine and γ-glutamyl-Se-methylselenocysteine in an unambiguous way prior to quantification by using either in-source fragmentation (LC-ESI-TOF-MS) or collision-induced dissociation (LC-ESI-Orbitrap MS). Finally, Se-methylselenocysteine (2.6 mg/kg as Se) and γ-glutamyl-Se-methylselenocysteine (1.2 mg/kg as Se) could contribute to the overall selenium recovery of 72 %. This sample is the first of the Faboideae subfamily and Phaseolus ssp. to be speciated to such an extent for selenium including γ-glutamyl-Se-methylselenocysteine, a highly potential selenium species, which makes this bean material an ideal candidate for functional food purposes.     

Some interrelated thermophysical properties of liquid water and ice. I. A user-friendly modeling review for food high-pressure processing

A bibliographic search yielded a set of empirical equations that constitute an easy method for the calculation of some thermophysical properties of both liquid water and ice I, properties that are involved in the modeling of thermal processes in the high-pressure domain, as required in the design of new high-pressure food processes. These properties, closely interrelated in their physical derivation and experimental measurement, are specific volume, specific isobaric heat capacity, thermal expansion coefficient, and isothermal compressibility coefficient. Where no single equation was found, an alternative method for calculation is proposed. Keeping in mind the intended applications and considering the availability of both experimental data and empirical equations, the limits for the set of equations where set in -40 to 120 degrees C and 0 to 500 MPa for liquid water and -30 to 0 degrees C and 0 to 210 MPa for ice I. The equations and methods selected for each property are described and their results analyzed. Their good agreement with many existing experimental data is discussed. In addition, the routines implemented for the calculation of these properties after the described equations are made available in the public domain.     

Internal quality and antioxidants content of cold-stored red sweet peppers as affected by polyethylene bag packaging and hot water treatment

Physical (weight, firmness) and compositional (sugars, organic acids, ascorbic acid, phenolic compounds and carotenoids) changes of red sweet peppers (Capsicum annuum L.) were monitored during 21 days of cold storage (at 7.5 °C); fruits were stored without packaging, packaged in low density polyethylene bags, or after hot water dipping (53 °C for 4 min) and packaging. Packaging prevented water loss, and preserved the firmness of the fresh product. Sugars (fructose and glucose) content was practically constant throughout the whole storage time, for all treatments. A moderate accumulation of citric acid was observed during storage, but no marked effects of packaging and hot water dipping on citric and malic acid content. Ascorbic acid content slightly increased in unpackaged and packaged fruits, but not in treated+packaged peppers. Hydroxycinnamics total content seemed not to be affected by cold storage, packaging or hot water treatment, whereas glycosylated flavonoids showed somewhat lowered levels during storage, particularly in the case of unpackaged and packaged+treated fruits. Regarding carotenoids content, the effect of the considered storage conditions seemed to be much smaller than that due to ripening stage. Provitamin A content showed an increasing trend in unpackaged and packaged fruits; packaged+treated peppers were characterised by a lower retention of provitamin A and a higher level of capsanthin and cucurbitaxanthin A with respect to not treated fruits. On the whole, packaging and hot water treatment did not produce noticeable adverse effects on the majority of the examined compositional quality parameters.     

Effects of organic farming on minerals contents and aroma composition of Clemenules mandarin juice

Consumers demand organic products because they believe that the organic products are more flavorful and respectful to the environment and human health. The effects of organic farming on the minerals contents and aroma composition of Clemenules mandarin juices were studied. Minerals (Fe, Cu, Mn, Zn, Ca, Mg, K, and Na) were quantified using atomic absorption-emission spectroscopy, while volatile compounds were extracted using the dynamic headspace technique and were identified and quantified by GC–MS. In general, organic farming produced a mandarin juice with a higher quality than that produced by conventional agricultural practices. Higher concentrations of both minerals and positive volatile compounds were found in the organic juice, while the formation of off-flavors was higher in the conventional juice, although threshold values were not reached.