Raw cow's milk inoculated with four laboratory strains (102−105 cfu/mL) of Mycobacterium avium ssp. paratuberculosis (Map) was pasteurized in a custom designed pilot plant pasteurizer having a maximum throughput of 580 L/h under turbulent flow conditions. Following 16 pasteurizer trials none of the Map strains survived high‐temperature short‐time conditions (72.5°C × 27 s) whether milk was homogenized or not. Two dairy herds containing animals which were faecal positive for Map were sourced and milk was collected for pasteurization studies. Milk collected from one herd on five occasions in the autumn did not contain any detectable Map organisms, and the second herd that was sampled on only one occasion in early winter was shown to contain Map at low concentration. Map was not detected in any of these milks following pasteurization at 72.5°C for 27 s. Two natural isolates of Map inoculated into milk were likewise inactivated on pasteurization.

Writing from his perspective as both a literary theorist and as an associate dean of the College of Arts and Sciences at New Mexico State University, Reed Way Dasenbrock suggests in his conclusion to this book that conventionalism has devastated the health of humanities departments. Without providing clear proof for his claim, Dasenbrock believes that there is "a direct connection" between the [End Page 403] apparent predominance of pragmatism and poststructuralism within the humanities and "the proletarianization of the profession"—caused by a decline in funding, the dramatic loss of tenure-track positions, and the proliferation of temporary appointments (249-50). "Our pragmatism," he argues, "has proved highly unpragmatic" (253). Dasenbrock's book is in part an effort to correct this problem: first, by his demonstration of the philosophical weaknesses of conventionalist positions, and then by his use of a few arguments (drawn from recent developments in analytic philosophy) about truth as a limit-condition. Given the context and the way he has set up the problem, Dasenbrock's arguments and conclusions will strike radical and liberal readers as concessions to the conservative politics that currently seem to be having their way with the humanities—even though he often claims to occupy the middle ground between these two opposing camps.

The effects of high-pressure (HP) treatment conditions on proteolysis in Cheddar cheese ripening were investigated by response surface analysis. A second-order central composite rotatable design (CCRD) was used to study the influences of pressure and processing time in the range 70–400 MPa and 3.5–81.5 h, respectively, at 25 °C. Separate control samples were maintained for equivalent times at 25 or 8 °C at atmospheric pressure. Urea-PAGE analysis indicated that breakdown of αs1-casein, and concomitant production of αs1-I-casein (f 24–199), was increased by treatment at 100 MPa for 70 h at 25 °C. Accumulation of αs1-I-casein did not increase at >225 MPa and, at 350–400 MPa, decreased accumulation of αs1-I-casein was observed. Response surface models indicated that treatment at pressures <150 MPa gave greatest increases in levels of pH 4.6-soluble N (SN), expressed as a percentage of total N (TN) in cheese, relative to control samples. As pressurisation time increased at <150 MPa, levels of pH 4.6-SN/TN in cheese increased. However, in general, HP reduced the production of free amino acids. Confocal laser scanning microscopy showed structural differences between Cheddar cheese treated at 350–400 MPa and control cheese stored at 25 °C or 8 °C. In summary, the application of relatively low pressures increased levels of primary proteolysis in Cheddar cheese. However, the temperature of pressurisation was a significant determinant of the overall effect of HP on proteolysis in Cheddar cheese.

Cheese starters (Lactococcus lactis strains 303, 223, 227 and AM2) were subjected to high pressure (HP) in the range 100–400MPa at 25°C for 20min either in 0.1m citrate buffer (pH 5.3), the same buffer containing 4.5% NaCl, or in cheese manufactured using each strain individually as a starter. Inactivation (total viable counts) and cell lysis (release of lactate dehydrogenase, LDH) of each strain were examined post-pressurisation. Starter bacteria were more pressure tolerant in cheese than in buffer. No evidence of release of LDH, and thus autolysis, from the starter cells resulting from HP treatment was observed either in buffer or in cheese. Primary proteolysis, studied by urea-PAGE analysis, increased as a result of the HP treatment. However, while cheeses made with different starter strains varied with respect to levels of pH 4.6 soluble nitrogen expressed as % total N and free amino acids, no further increase in these parameters were observed due to HP treatment. Thus, HP treatment for 20min inactivated starter bacteria in Cheddar cheese (2–5 log cycle reduction at 400MPa), but did not induce autolysis.

Low-moisture Mozzarella cheese (LMMC) was high pressure (HP) treated at different stages of storage at 4°C and analysed immediately post HP treatment. Confocal laser scanning microscopy of the unheated cheese indicated that HP treatment enhanced the development of age-related swelling of the paracasein matrix. This microstructural change coincided with a reduction in the level of serum expressed on centrifugation and suggests that HP results in an increase in the water holding capacity of the paracasein matrix. Proteolysis, as measured by urea polyacrylamide gel electrophoresis (urea-PAGE), pH 4.6 water soluble nitrogen and total levels of free amino acids (FAA), was largely unaffected by HP treatment of LMMC. HP treatment resulted in an increase in the flowability and a reduction in the melt time on heating at 280°C, especially at storage times ≤15 days. Dynamic measurement of the viscoelastic changes on heating the cheese from 20 to 82°C showed that HP treatment resulted in an increase in the fluidity of the heated cheese, as measured by phase angle, especially in 1-day-old cheese. Thus, accelerated ripening of LMMC was induced by HP treatment, which may lead to the development of an industrial process if cost effective commercial HP equipment were available.

High pressure (HP) treatment has emerged as a food processing technology primarily due to increasing interest in novel methods for preservation of foods. Applying HP to food products modifies interactions between individual components, influences rates of enzymatic reactions and can inactivate microorganisms. This paper reviews studies of HP induced changes in milk relevant to cheesemaking, including the effects of HP on rennet coagulation time, rate of curd formation and cheese yield. Published studies on the effects of direct HP treatment of cheese and specifically the effects of HP on cheese ripening characteristics, functionality and microbiology, are also reviewed.

The microbiological and chemical composition of three batches of two different smear-ripened cheeses, made from raw milk, were examined during 42 days of ripening. The pH of the rind increased rapidly from 5.0 to 6.7 in 42 days compared to a more gradual increase from 4.7 to 5.4 in the core. Considerable differences were observed between the microbial populations of the core and of the rind during ripening. The number of coliforms, E. coli and Staphylococcus aureus, initially present in the core of both cheeses ex-brine were < 10(3) colony forming units (cfu) per g, and declined to undetectable levels at the conclusion of ripening. Pn contrast, enterococci in the core of both cheeses (initial levels 10(5) cfu/g), either remained static or showed a slight decrease throughout ripening while lactococci declined slightly from 10(8) to 10(6) cfu/g and the numbers of lactobacilli increased from initial levels of 10(5) to 10(8) cfu/g after 42 days of ripening. The number of coliforms, and enterococci on the rind of both cheeses increased during the ripening while that of Staphylococcus aureus remained constant in the case of one cheese and increased on the rind of the other cheese. The numbers of E. coli declined to undetectable levels on the rind of one cheese and remained relatively constant at 10(4) cfu/g on the rind of the other cheese. These results indicate that conditions on the rind provide a suitable environment for the growth and/or survival of undesirable bacteria in these varieties of soft cheeses.

The influence of high pressure (HP) on the stability and activity of the milk alkaline pro- teinase plasmin was examined. Assays of enzyme activity following HP treatment of plasmin in phosphate buffer (pH 6.7) indicated that the enzyme was extremely pressure stable, retaining almost all activity even after treatment at 600 MPa for 20 min at 20 °C. Plasmin was also extremely stable when HP treated in buffer containing 25 mg.mL -1 sodium caseinate, and in cheese. However, HP treat- ment in buffer containing 5 mg.mL -1 β-lactoglobulin resulted in enzyme inactivation at pressures > 400 MPa, indicating that the presence of β-lactoglobulin greatly destabilises the enzyme under high pressure, which is analogous to the effect of this protein on the heat stability of plasmin. In separate experiments, hydrolysis of β-casein by plasmin at 20 °C for 30 min at various pressures (300-800 MPa) was studied. Parallel control incubations were performed at atmospheric pressure. Urea-PAGE analysis of digests showed that primary proteolysis of β-casein was decreased at P > 400 MPa. As judged from RP-HPLC analysis, production of 2%-TCA soluble peptides by plas- min appeared unaffected at P < 700 MPa, above which pressure the rates of peptide production decreased. Overall, plasmin is relatively pressure stable in most systems and can hydrolyse its pre- ferred substrate (β-casein) at pressures up to 700 MPa, but is sensitive to destabilisation by denatured β-lactoglobulin. plasmin / high pressure / specificity / stability

The effects of high pressure (HP) on plasmin activity, β-lactoglobulin denaturation and proteolysis during subsequent storage of HP treated milk, were studied. Fresh raw milk samples were exposed to a range of pressures from 50 to 800MPa, for times of 1, 10 or 30min, at 20°C. Residual plasmin activity and whey protein denaturation were measured immediately post HP-treatment. Indices of proteolysis were measured during post-HP storage. Treatment at pressures >300MPa resulted in extensive β-lactoglobulin denaturation. Plasmin activity decreased in milk treated at pressures ⩾400MPa; the loss of activity was not well correlated with β-lactoglobulin denaturation. Compared to raw milk, treatment at 50MPa had little effect on proteolysis during storage of treated milk measured as increases in pH 4.6-soluble N and liberation of proteose peptones, but at pressures of 300–400MPa, proteolysis was increased relative to raw milk. After pressurisation >500MPa, proteolysis during storage of milk was less than that observed in raw milk. Overall, HP influenced proteolysis in milk in a way which is different from that produced by heat, in terms of subsequent susceptibility of casein to proteolysis during storage or incubation. In particular, HP treatment at pressures of 300–500MPa can increase proteolysis in milk, possibly through changes in micelle structure facilitating increased availability of substrate bonds to plasmin, which has implications for products prepared from milk thus treated.

ABSTRACT The objective of this study was to determine the effect of high pressure (HP) on the inactivation of microbial contaminants in Cheddar cheese ( Escherichia coli K-12, Staphylococcus aureus ATCC 6538, and Penicillium roqueforti IMI 297987). Initially, cheese slurries inoculated with E. coli , S. aureus , and P. roqueforti were used as a convenient means to define the effects of a range of pressures and temperatures on the viability of these microorganisms. Cheese slurries were subjected to pressures of 50 to 800 MPa for 20 min at temperatures of 10, 20, and 30°C. At 400 MPa, the viability of P. roqueforti in cheese slurry decreased by >2-log-unit cycles at 10°C and by 6-log-unit cycles at temperatures of 20 and 30°C. S. aureus and E. coli were not detected after HP treatments in cheese slurry of >600 MPa at 20°C and >400 MPa at 30°C, respectively. In addition to cell death, the presence of sublethally injured cells in HP-treated slurries was demonstrated by differential plating using nonselective agar incorporating salt or glucose. Kinetic experiments of HP inactivation demonstrated that increasing the pressure from 300 to 400 MPa resulted in a higher degree of inactivation than increasing the pressurization time from 0 to 60 min, indicating a greater antimicrobial impact of pressure. Selected conditions were subsequently tested on Cheddar cheese by adding the isolates to cheese milk and pressure treating the resultant cheeses at 100 to 500 MPa for 20 min at 20°C. The relative sensitivities of the isolates to HP in Cheddar cheese were similar to those observed in the cheese slurry, i.e., P. roqueforti was more sensitive than E. coli , which was more sensitive than S. aureus . The organisms were more sensitive to pressure in cheese than slurry, especially with E. coli . On comparison of the sensitivities of the microorganisms in a pH 5.3 phosphate buffer, cheese slurry, and Cheddar cheese, greatest sensitivity to HP was shown in the pH 5.3 phosphate buffer by S. aureus and P. roqueforti while greatest sensitivity to HP by E. coli was exhibited in Cheddar cheese. Therefore, the medium in which the microorganisms are treated is an important determinant of the level of inactivation observed.

The possibility of acceleration of commercial Cheddar cheese ripening by exposure to a high pressure (HP) treatment of 50 MPa for 3 days at 25°C at different stages of ripening was investigated. Proteolysis was examined in the treated and untreated cheeses by measurement of pH 4.6 water soluble nitrogen, expressed as g/100 g total N (pH 4.6 SN/TN), urea-PAGE, reverse phase (RP) HPLC, analysis of molecular mass distribution by gel permeation and measurement of free amino acids (FAA) in the pH 4.6 SN. There was an immediate increase in pH 4.6 SN/TN and FAA in cheese HP-treated at 2 days of age, although this effect decreased with cheese age. Urea-PAGE analysis of cheese samples indicated that HP treatment accelerated degradation of αs1-casein and accumulation of αs1-I-casein (f 24-199). RP-HPLC profiles indicated quantitative but not qualitative differences between treated and non-treated samples. Confocal laser scanning microscopy did not indicate any gross structural changes in the cheese matrix as a result of exposure to 50 MPa for 3 days at 25°C. It was concluded that the enhancement of proteolysis observed may be attributed to a combination of the temperature and pressure used in the treatment.

The survival and growth of Bacillus stearothermophilus and Bacillus licheniformis, naturally present (30–300 colony forming units/ml) in late season skim milk, was monitored in a three effect evaporator during low heat skim milk powder manufacture. Substantial growth was shown to occur in the preheating stages prior to direct steam heating. A typical heat treatment (77°C, 15 s) used in the manufacture of low heat powder did not inactivate the bacteria, which continued to grow in the heater. The importance of preheaters in influencing thermophile growth in the evaporator is demonstrated by the finding that growth in the preheater stages was accompanied by growth in subsequent evaporator effects which significantly exceeded that observed when the final two preheaters were bypassed. A mid‐run mini‐clean procedure incorporating 0.2% hydrogen peroxide for decontaminating the evaporator was tested and may prove useful in extending evaporator run times

It is now recognised that physical and chemical factors such as temperature, pH, salt and lactate concentrations are prime determinants of microbial growth in foods. These interact in a complex and synergistic manner to control the growth of microorganisms and such interactions can now be rapidly computed. The main growth parameters for Listeria monocytogenes i.e. duration of the lag phase and generation times, were quantified with respect to the controlling factors and a database constructed for growth of the pathogen in a skim milk medium. Results show that the models give reasonable predictive estimates for growth of this pathogen in milk and dairy products such as processed milk, cream and soft cheese. The computed information base allows rapid assessment of the growth potential of the pathogen in a particular food environment and defines conditions under which any adventitious contaminants will not grow. This has potential for use in positive release of hygienically manufactured product into the market place, and for defining refrigeration and temperature abuse conditions which are critical in determining growth of the organism.

While attempting to capture systematic relations between form and meaning, transformational grammar has relied upon several tools for analysis. Though the generative enterprise has promised to capture linguistically significant generalizations and in doing so provide an explanatory account of linguistic phenomena, some of these generalizations are impossible to capture in terms of these tools. This is primarily due to a fundamental shortcoming of the mechanisms employed most often in transformatio nal approaches; that is, that many linguistically significant generalizations cannot be expressed by means of a derivational relationship. This paper attempts to lay the groundwork for the analysis of prototypical transitive predicates, in which syntactic and functional equivalency of constructions is captured in terms of direct surface relationships as opposed to derived equivalencies. This is accomplished by means of a 'fuzzy' evaluation metric on the topicality of signs, based upon data from Polish word order in Siewierska's (1993) study.

The framework of Head-Driven Phrase Structure Grammar (HPSG) boasts many elegant analyses of syntactic and semantic phenomena. However, little emphasis to date has been placed on syntactic structures when influenced by semantic or pragmatic considerations, such as that of theme and rheme in languages like Russian. Clearly, Russian grammar follows other principles, but the role of contextual information is crucial to determining word order and intonational patterns; these are facts which are hard to reconcile with generative frameworks which have no account of pragmatics. This paper seeks to lay the foundation for an analysis of pragmatic concerns in HPSG, building from analyses by Pollard and Sag (1987, 1994), and concentrating on the ‘simplest’ examples of literary Russian. In a language like Russian, with a high degree of case marking, it is unsurprising to find very free word order. However, there is an important constraint on word order; Russian divides of sentences into two parts: one of old information, and one of new information. Such an analysis, that of the functional sentence perspective, labels these parts topic and comment or theme and rheme. Their purpose, roughly, is that the theme indicates the subject of the utterance, and the rheme conveys new information essential to the speaker (Krylova and Khavronina 1988:11). Just what part of the sentence qualifies for these roles may depend on any number of different factors, including such elusive phenomena as the emotional state of the speaker and intonational patterns involved; herein lies the problem of a generative analysis of the facts.

Ripening of cheese, hard varieties in particular, can be a long and costly process. Much research interest has focused on methods to accelerate ripening either by manipulation of the cheese manufacture or ripening procedures. Recent reports have indicated that the application of high pressure (HP) can have a dramatic effect on the rate at which some cheese types ripen. This review will examine the current approaches for accelerated ripening of cheese and report on recent developments in the application of HP in this area.

A predictive model based on growth of Listeria monocytogenes in milk is described. The main aim of this work was to generate a predictive model in milk acidified with lactic acid to mimic conditions found in a range of dairy products. A complete factorial design was employed to determine the effects of pH (4·5‐7·5), temperature (3·35°C) and salt concentration (0‐8%) on growth of the organism. There were 210 design points and growth curves were individually fitted for the Gompertz function using non‐linear regression. Descriptors of the curves, such as lag phase duration (LPD), exponential growth rate (EGR) and generation time (GT) were calculated and polynomial models were developed relating these to pH, temperature and salt concentration. The selected cubic polynomial model gave acceptable predictive estimates of growth and was stable, i.e. predictions were repeatable over the range of environmental variables studied. The model was further tested to determine its capacity for predicting growth of listeria in a range of dairy foods and these validation studies confirm its usefulness as a rapid means for estimating growth of the organism under specified environmental conditions.

The ability of the components of nitrogenase from free-living nitrogen-fixing bacteria to cross-react and form active enzyme complexes with the components of the enzyme isolated from a symbiotic nitrogen-fixing system was tested. Nitrogenase components of Azotobacter vinelandii, Bacillus polymyxa cross-reacted with components of nitrogenase from Rhizobium japonicum bacteroids. No evidence of a cross reaction was obtained in the case of Clostridium pasteurianum.