Aged Cheese Research Articles

MAOI Skin Patch May Come With Fewer Warnings

Back to table of contents Next article Government NewsFull AccessMAOI Skin Patch May Come With Fewer WarningsJim RosackJim RosackSearch for more papers by this authorPublished Online:16 Dec 2005https://doi.org/10.1176/pn.40.24.0001The lowest dose of a new transdermal formulation of selegiline, a monoamine oxidase inhibitor (MAOI) antidepressant, should not be required to carry long-standing warnings about avoiding dietary intake of foods high in tyramine, an advisory panel of the U.S. Food and Drug Administration (FDA) told the agency.Joseph Berger, M.D. (left), discusses an action paper with colleague Ray Freebury, M.D., at last month's meeting of the APA Assembly. Berger and Freebury are the representatives from the Ontario District Branch. See page Original article: 9 for coverage of the meeting.David HathcoxBy a vote of 7-4, members of the FDA's Psychopharmacologic Drugs Advisory Committee (PDAC) recommended in October that the 20 mg skin patch be marketed without the restrictions found on all MAOIs marketed to date. In a second vote by the same count, PDAC members said it was permissible to market the 20 mg patch without dietary restrictions, even if two higher doses carried the warnings. Final approval is expected in the first half of 2006.The selegiline transdermal patch—to be marketed by Somerset Pharmaceuticals under the trade name Emsam—will be available in 20 mg, 30 mg, and 40 mg strengths. Somerset had already reached agreement with the FDA that the two higher doses will carry the standard dietary warning; however, the company said the lowest dose was safe and should be marketed without any need for patients to watch their diets.Because an internal FDA review of the data concluded that all three doses should carry dietary restrictions, the agency chose to put the issue before the advisory committee.The PDAC's recommendations are not binding on the agency, which will make a final decision on the labeling for the patches within the next few months. Somerset (a joint venture of Mylan and Watson Pharmaceuticals) received tentative FDA marketing approval for 20 mg, 30 mg, and 40 mg doses of selegine in January 2004; however, the agency expressed concern about the safety of the drug and the need for dietary restrictions. Somerset filed its response to those concerns this past May 26.Selegiline is a nonselective MAOI, inhibiting not only the MAO-B enzyme in the central nervous system, but also MAO-A elsewhere in the body. In the digestive tract, MAO-A normally metabolizes tyramine, a dietary amine that is found in high concentrations in foods such as aged cheese and red wine.The breakdown of tyramine in the gut prevents significant amounts of it from being absorbed and circulated throughout the body. Tyramine is a potent pressor— leading to constriction of blood vessels— which ultimately results in increased blood pressure. High amounts of tyramine can lead to hypertensive crises, resulting in stroke, heart attack, and even death.Because the medication is absorbed from the skin patch and bypasses the gut wall, it is thought that transdermal selegiline will have a significantly reduced effect on MAO-A in the digestive tract. In addition, at lower doses, selegiline is thought to inhibit MAO-B preferentially, while at higher doses both A and B isoenzymes are effected. With significantly reduced inhibition of digestive tract MAO-A, dietary restrictions would not be necessary, the company argued.Thomas Laughren, M.D., head of psychiatry products at the FDA, wrote in a memo to PDAC members, “Having to worry about diet is a major disincentive to using the orally available MAOIs in the U.S.”Appearing before the committee, FDA staff reviewer Greg Dubitsky, M.D., strongly argued that the clinical trial data regarding tyramine sensitivity in patients wearing selegiline patches was highly variable, and for that reason said he could not conclude that it was safe to market the 20 mg dose without dietary restrictions. He urged that dietary warnings be put on the labels of all three doses of the patch.In the end, though, the majority of PDAC members were not swayed by Dubitsky's argument.“I am convinced that there is no harm signal in either the clinical trials data that were represented or the more extensive database for the use of Eldepryl [selegiline in pill form],” said Wayne Goodman, M.D., PDAC chair and a professor of psychiatry at the University of Florida.Goodman said that “benefit is clearly an issue here,” noting the unique new dose formulation will present patients with an entirely new option. “We do have other MAOIs on the market,” he said,“ but it's clear to me that this is going to produce far less risk than our existing medications.”More information on the PDAC's consideration of Emsam is posted at<www.fda.gov/ohrms/dockets/ac/05/briefing/disclaimer.htm>.▪ ISSUES NewArchived

Enrichment of Cheeses Manufactured from Cow's and Sheep's Milk Blends with Sheep-like Species-Related Alkylphenols

Enhancement of concentrations of species-related sheep-like alkylphenols, p- and m-cresols and 3- and 4-ethylphenols, in experimental Manchego-type cheeses manufactured from cow's and sheep's milk blends (80:20) by using arylsulfatases was investigated. A food-grade arylsulfatase from Aspergillus oryzae (ATCC 20719) was produced using a stimulatory medium, and crude dried cells were used as the enzyme source. Exogenous arylsulfatases from Helix pomatia and A. oryzae were added to cheese curd, and the amounts of species-related alkylphenols were measured. Arylsulfatase from H. pomatia released limited amounts of alkylphenols in the cheese only when used at a high level. Arylsulfatase from A. oryzae released substantial amounts of alkylphenols during 2 months of ripening. The concentrations of alkylphenols in A. oryzae arylsulfatase-treated cheese were comparable to the previously reported levels present in aged Manchego-type cheeses manufactured from pure sheep's milk.

Reduced-fat cheddar cheese manufactured using a novel fat removal process.

Normally, reduced-fat Cheddar cheese is made by removal of fat from milk prior to cheese making. Typical aged flavor may not develop when 50% reduced-fat Cheddar cheese is produced by this approach. Moreover, the texture of the reduced-fat cheeses produced by the current method may often be hard and rubbery. Previous researchers have demonstrated that aged Cheddar cheese flavor intensity resides in the water-soluble fraction. Therefore, we investigated the feasibility of fat removal after the aging of Cheddar cheese. We hypothesized the typical aged cheese flavor would remain with the cheese following fat removal. A physical process for the removal of fat from full-fat aged Cheddar cheese was developed. The efficiency of fat removal at various temperatures, gravitational forces, and for various durations of applied forces was determined. Temperature had the greatest effect on the removal of fat. Gravitational force and the duration of applied force were less important at higher temperatures. A positive linear relationship between temperature and fat removal was observed from 20 to 33 degrees C. Conditions of 30 degrees C and 23,500 x g for 5 min removed 50% of the fat. The removed fat had some aroma but little or no taste. The fatty acid composition, triglyceride molecular weight distribution, and melting profile of the fat retained in the reduced-fat cheeses were all consistent with a slight increase in the proportion of saturated fat relative to the full-fat cheeses. The process of fat removal decreased the grams of saturated fat per serving of cheese from 6.30 to 3.11 g. The flavor intensity of the reduced-fat cheeses were at least as intense as the full-fat cheeses.

Evidence-Based Treatment of BPD: Not an Oxymoron

Back to table of contents Previous article Next article From the PresidentFull AccessEvidence-Based Treatment of BPD: Not an OxymoronMarcia Goin, M.D.Marcia GoinSearch for more papers by this author, M.D.Published Online:19 Sep 2003https://doi.org/10.1176/pn.38.18.0003Hearing the title of my scheduled talk, “Evidence-Based Treatment of Borderline Personality Disorder (BPD),” colleagues kidded me, saying. “Marcia, that’s an oxymoron—a concept as paradoxical as ‘airplane food’ or ‘postal service.’ ‘Evidence?’ There’s not enough ‘evidence’ on which to base the treatment of BPD.”This reaction reflects common misperceptions about what constitutes “evidence-based medicine.” Similar misperceptions probably prompted David Sackett, one of the founders of the process, to write the paper “Evidence-Based Medicine: What It Is and What It Isn’t: Its About Integrating Individual Clinical Expertise and the Best External Evidence” (BMJ1996; 312:71-72).As Sackett stated, evidence-based medicine is not about making decisions based solely on the results of controlled studies. It is not about providing a cookbook approach or clinging rigidly to algorithms or reifying evidence. It is about being clinically and culturally sensitive and evidence informed. Formulate the question, search for answers, appraise the evidence, apply the results, and assess the outcome.APA’s Practice Guideline Development Process for BPDThe DSM-III publication in 1980 was the first time borderline personality was officially defined. In 1989 APA convened a task force to review the possibility of developing a treatment guideline for patients with borderline personality disorder. The group appreciated that such treatment is very difficult; it is associated with severe transference and countertransference problems and has a highly variable outcome. The questions were there, but there was not enough material in the literature to enable APA to develop a treatment guideline.The question of a guideline was revisited in 1999, at which time there was a fair-sized database that included some randomized controlled studies. The guideline is not as evidence rich as the treatment guideline for bipolar illness, which cites 492 references, but with 198 references, the BPD guideline is certainly not evidence poor. In the BPD guideline, important references to clinical trials comparing the efficacy of different psychopharmacologic approaches to symptom spectra commonly suffered by these patients are noted. The evidence also includes four published randomized, controlled studies of psychotherapy. These were all long term, and one paper had an 18-month follow-up with impressive positive data.Explicating Evidence-Based MedicineTo quote Sackett again, “It [evidence-based medicine] is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients.” An example in the guideline of this principle is the recommendations regarding the use of MAO inhibitors. Although the efficacy of MAO inhibitors is equal to that of SSRIs for reducing affective dysregulation in patients with BPD, they are not a first-line choice in the treatment algorithm. In the context of informed consent for the use of MAO inhibitors, safety considerations are heightened for patients who are impulsive and suicidally vulnerable. The potentiation of sympathomimetic drugs or related compounds by MAO inhibitors may produce hypertensive crises. High concentrations of tyramine or dopamine in aged cheese, beer, wine, liver, dry sausage, fava beans, and excessive intake of caffeine may also generate hypertensive crises. Impulsive or suicidal patients may forget or purposely ignore these dietary limitations. Treatment with an SSRI avoids this considerable risk.Evidence-based medicine requires us to evaluate the validity and reliability of the available evidence, but not lose sight of the limitations of this evidence. Common problems are that trials are small, have a short duration, rely on surrogate outcomes, or use controls of uncertain validity. Presented with internally valid, well-conducted trials, sensitive clinicians will still face the need to determine how to apply this evidence to our individual patients.Psychiatrists practicing evidence based-medicine will identify and apply the most efficacious interventions to maximize the quality of life for their patients. This is not a cost-saving device. Adoption of this clinical strategy may raise rather than lower the cost of patient care.Is evidence-based treatment of patients suffering from BPD an oxymoron?The answer is clearly “No.” Unfortunately, we can’t say the same for airline food or postal service. ▪ ISSUES NewArchived

Development of defined surface starter cultures for the ripening of smear cheeses

Abstract For the surface ripened smear cheese varieties it is still general practice to use the mature smear of aged cheeses for the treatment of young cheeses (old–young smearing). The associated hygienic problems are obvious; saprophytic or pathogenic bacteria as well as moulds can become part of the house microflora and can persist over long periods of time by this in-house contamination cycle. This paper summarises studies of the past 8 years aiming to establish defined surface starters for the ripening of Tilsit-type smear cheeses performed in the microbiology department of the Federal Dairy Research Center, Kiel, Germany and currently in a cooperative EU project (FAIR programme, CT98-4220, 1999–2001). Growth on cheese (lab scale) of the five strain minimal starter developed is now comparable to that of a typical old–young smear “starter”. A complete smear layer is developed within 4–7 days. It consists of the yeast Debaryomyces hansenii , and the bacteria Brevibacterium linens , Arthrobacter nicotianae , Corynebacterium ammoniagenes , and Staphylococcus equorum . When defined starters were tested on pilot scale, a too weak sulphury volatile flavour was observed compared to the old–young smeared control cheeses. Some of the key sulphur components (methanethiol and derivatives), some alcohols and aldehydes were produced at lower levels by the defined starters. The development of typical light-brown cheese colour (so-called “red smear”) was attributed to the interactions between yellow-pigmented Arthrobacter spp . and proteolytic bacteria. The orange pigments of B. linens and staphylococci were found to be of lesser importance. The role of Corynebacterium species which show fast growth, is still not clear. An impact of this predominant part of the smear flora on aroma- and colour development can be expected. However, clear effects were not observed in experiments in model systems.

Accumulation of Free L-Glutamic Acid in Full- and Reduced-fat Cheddar Cheese Ripened at Different Time/temperature Conditions

Influence of ripening conditions on accumulation of free L-glutamic acid (FGA) in full (FF)- and reduced-fat (RF) Cheddar cheese was investigated. Cheeses were ripened isothermally at 5 and 8°C for 6 months; aged at 5 and 8°C for 1 and 2 months and then at 8 and 5°C, respectively, for 5 and 4 months, respectively; or aged for 1 and 2 months at the latter temperatures and then again at 5 or 8°C for 4 and 3 months, respectively. In all cases, accumulation of FGA correlated well with accumulation of soluble nitrogen-containing fractions of cheese and, for isothermally aged cheeses, was linearly related to cheese age. Results suggested that level of FGA might be considered a ripening index in both FF and RF Cheddar. Level of FGA in cheese ripened at 8°C was significantly higher than that in cheese ripened at 5°C and, at a given aging conditions, level of FGA in FF cheese was significantly lower than that in RF cheeses. Increasing or decreasing aging temperature by 3°C at different cheese ages resulted in cheese-specific FGA levels that differed significantly from those obtained with cheeses ripened isothermally at 8°C or 5°C. Accumulation of FGA was influenced by effects of aging conditions and cheese composition on cheese-age-specific proteolytic activities in cheese. Results suggested that small changes in aging temperature, at desired stages during aging, may offer opportunities in controlling and modulating rate and extent of proteolytic activities during cheese aging and thus provide tools to better modulate the development of cheese quality attributes.

The anticarcinogenic conjugated fatty acid c9, t11-c18:2, or rumenic acid, in human milk: amounts and effects.

The conjugated linoleic acid (CLA) c9, t11-C18:2 has been detected in human milk by gas-liquid chromotography (GLC) using standards for tentative identification. The amounts found were: 5.5 mg/g fat, Australia, 1988; and 3.6 mg/g fat, Idaho, 1997. We also employed GLC and standards and confirmed the identity of coeluting peaks by mass spectrometry. Our values were 1.8+/-0.02 mg/g fat. CLA inhibits growth of several cancers, is antiatherosclerotic, partially overcomes catabolic responses to endotoxin injection, enhances weight gain and improves feed efficiency in rats, and modulates immune response and bone deposition. The dietary sources are ruminant-derived foods, particularly aged cheese.

Clarifying the Safety of the MAOI Diet and Pizza

Article AbstractLetter to the Editor Sir: We appreciated Drs. Shulman and Walker's study attemptingto clarify and extend our clinical experience demonstratingthe apparent safety of ingesting at least some types ofpizza along with a monoamine oxidase inhibitor (MAOI). Theirstudies clarifying the specifics of the MAOI diet have been aninvaluable aid to all clinicians who prescribe these important antidepressantmedications.Our premise in noting the safety of MAOI-treated patients†ingesting kosher pizza was based on the fact that kosher pizzaestablishments do not generally use aged cheeses as a topping.

Refining the MAOI Diet

Continuous refinement of the monoamine oxidase inhibitor (MAOI) diet has resulted in much reduced and simplified recommendations that attempt to balance safety and practicality. In the spirit of evidence-based practice, dietary restrictions should be based on carefully documented case reports and valid tyramine analyses. Residual concerns have focused on combination foods such as pizza and a variety of soy products. We determined the tyramine content of pizzas and a variety of soy products in order to refine dietary recommendations for use with MAOIs. High-pressure liquid chromatography analysis of tyramine content was performed on a variety of pizzas, soy sauces, and other soybean products. A tyramine level of 6 mg or less was considered safe. No significant tyramine levels were found in any of the pizzas, including those with double pepperoni and double cheese. Marked variability was found in soy products, including clinically significant tyramine levels in tofu when stored for a week and high tyramine content in one of the soy sauces. Pizzas from large chain commercial outlets are safe for consumption with MAOIs. However, caution must be exercised if ordering pizzas from smaller outlets or gourmet pizzas known to contain aged cheeses. All soybean products should be avoided, especially soy sauce and tofu. Individualized counseling and continuous surveillance of compliance are still essential.

A reverse‐phase high‐performance liquid chromatographic method for analyzing complex mixtures of triglycerides. Application to the fat fraction of an aged cheese

AbstractAnalysis of complex mixtures of triglycerides that span a broad range of partition numbers can entail a number of difficulties. The present study was therefore intended to develop a method of reverse‐phase high‐performance liquid chromatography using a light scattering detector for analyzing such mixtures. Stationary phase type, mobile phase gradient, column temperature, and injection solvent were the factors used to develop the method. The method improved the selectivity of critical pairs of milk fat triglycerides, providing good resolution for 115 peaks with partition numbers of between 22 and 53. The use of tristearin as internal standard and the relative response factors for different partition number ranges made it possible to more accurately estimate the weight of the sample triglycerides.

Danone—Serdika J.S. Co.

A joint venture was set up between the Danone Group, the world's largest producer of fresh dairy products, and Serdika-Sofia, the most popular Bulgarian state-owned firm for milk and dairy products with the biggest market share. The new company specializes in yogurt production. Dairy products form the greatest share of products in the range of the output variety of the BSN, or from July 1994, the Danone Group, totaling a 28.8 percent share; followed by grocery products, 18.7 percent; biscuits, 16.3 percent; international, 10.0 percent; beer, 9.2 percent; mineral water, 8.9 percent; and containers, 8.1 percent, as of the end of 1994. Danone Group's 1994 consolidated sales totaled up to FF 76.8 billion and those of dairy products, FF 24.2 billion. The sales structure of dairy products is the following: * fresh cheese, 32.4 percent; * yogurt, 31.0 percent; * desserts, 14.3 percent; * aged Italian cheeses, 10.9 percent; * others, 11.4 percent.

Factors Affecting the Conjugated Linoleic Acid Content of Cheddar Cheese

The effects of package type (cans and nylon vacuum pouches), milling pH (5.5, 5.7, and 5.9), additives [butylated hydroxyanisole (BHA), tyrosine, and lysine], and aging (0, 1, 3, and 6 months) on the conjugated linoleic acid (CLA) content of Cheddar cheese was determined. Fatty acid distributions and CLA, moisture, protein, lipid, and titratable acidity contents in raw milk and aged cheeses were determined. The CLA content in canned cheese (3.03 mg/g lipid) was significantly higher than in a vacuum pouch packed cheese (2.70 mg/g lipid) after 6 months of aging. Milling pHs of 5.5 and 5.9 and the addition of BHA, tyrosine, and lysine resulted in significantly lower CLA contents in cheeses aged for 6 months than the control. Multiple linear regression showed that lipid and protein contents contributed to CLA content positively. The content of oleic acid contributed significantly to the relationship between CLA and fatty acids. Keywords: Conjugated linoleic acid; Cheddar cheese; anticarcinogen

Aging-Induced Changes in Populations of Lactococci, Lactobacilli, and Aerobic Microorganisms in Low-Fat and Full-Fat Cheddar Cheese

The objective of this study was to observe the impact of lowering fat content on the microflora of Cheddar cheese. Full-fat (32%) and low-fat (5%) Cheddar cheeses were produced and evaluated one day after manufacture and at monthly intervals for 5 months. The cheeses were aged at 4°C after being dipped in mold inhibitor and vacuum packed in high-density polythene bags. Standard plate counts and counts of lactococci and lactobacilli were performed. Transmission and scanning electron microscopy of the microflora were also conducted. The lactococci decreased gradually over the ripening period, while the lactobacilli, though not knowingly added during Cheddar cheese preparation, increased concomitantly. Transmission electron microscopic observations revealed affinity of lactococci for the fat phase in aged cheese.

Determination of total solids in dairy products using the microwave‐oven method

SummaryMicrowave‐oven and air‐oven methods were compared in the determination of total solids in various dairy products (plain yogurt, flavoured yogurt, soft cheese, aged cheese and butter). the microwave‐oven method considerably reduced drying time. For the cheeses and butter the drying times were 10 and 20 min respectively. Precision levels were not satisfactory in the case of yogurts.

Contribution of milk-clotting enzymes and plasmin to cheese ripening.

Cheese ripening involves several biochemical processes including: proteolysis, lipolysis and lactose/lactate metabolism. Of these processes, proteolysis is most significant because it results in the breakdown of the structural network of casein formed during cheese manufacture, thereby transforming a rubbery “green” cheese to a soft and smooth aged (mature) cheese. Proteolysis also enhances the release of flavor compounds during maturation (ripening) of cheese. The major proteolytic changes that occur in cheese during ripening are summarized in the following reaction steps: I. protein-----------------→large peptides II. large peptides ---------------→ small peptides, tripeptides, dipeptides III. small peptides --------------→ amino acids, amides and ammonia KeywordsBovine MilkCasein MicelleCheddar CheesePlasmin ActivityCheese MilkThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Cheddar Cheese Aging: Changes in Sensory Attributes and Consumer Acceptance

ABSTRACTThe objectives of this study were to identify and quantify changes in sensory attributes of Cheddar cheese as it ages, determine how such changes relate to liking, and predict liking for aged cheese from sensory attributes at a young age. Sensory attributes of 14 cheeses were measured by descriptive analysis of the products from 2 wk to 9 mo. Consumers rated their liking for the products when the cheeses were 3, 6 and 9 mo old. Strong flavors, off‐flavors, and ‘young’ flavors increased in intensity as the cheeses aged. Off‐flavors correlated negatively with liking and ‘young’ flavors correlated positively with liking regardless of age of the cheeses.

Comparisons between the electrophoretic pattern and textural assessment of aged Cheddar cheese made using various levels of calf rennet or microbial coagulant (Rennilase 46L)

The set-to-cut time, rennet concentration and set temperature were varied during the commercial manufacture of Cheddar cheese in nine Damrow cheese vats on each of three consecutive days. In addition, in two separate pilot plant trials, the setting conditions and coagulant type (calf rennet or Rennilase) were varied during early and mid-season manufacture of Cheddar cheese. The effect of variations on proteolysis were assessed by measuring the non-casein nitrogen (NCN) and the non-protein nitrogen (NPN) content of the cheese. Protein degradation was also estimated by determining the breakdown of αS1 and β-caseins using polyacrylamide gel electrophoresis (PAGE), at intervals over a six-month period. At the same time, changes in cheese texture were assessed by a trained panel. NPN levels were similar in all cheeses and tended to increase slightly over the six month period. The NCN level increased markedly in cheese from both pilot plant trials but less so in cheese from the commercial trial due to a lower moisture content and a higher pH. The specificity and activity of Rennilase differed from that of calf rennet and this was reflected in sharply elevated NCN levels during early maturation. The breakdown of αS1-casein was both rapid and extensive when calf rennet was used as the coagulant. The degradation of β-casein was greater in cheese produced with Rennilase than with calf rennet. Higher residual coagulant levels in the cheese due to the increasing concentrations of rennet (10·6, 16·0 and 24·0 ml/100 litres milk) and Rennilase (4·6, 7·0 and 10·5 ml/100 litres milk) used initially were reflected in the significant (P < 0·001) early breakdown of αS1-casein. In spite of the significant variation in the early breakdown of αS1-casein, sensory evaluation of the textural characteristics of the cheese was not sensitive to a variation in coagulant concentration. Cheese made using Rennilase was significantly (P < 0·001) less rubbery, less smooth, firmer and grittier than cheese made using calf rennet but differences were small, suggesting that the type of coagulant had little effect on sensory scores. Independent of rennet concentration and set temperature during commercial cheese manufacture, the rate of breakdown of αS1-casein was higher for a 50-min set-to-cut time than for a 30-min set-to-cut time. The degradation of β-casein was not influenced to the same extent. As the variation in αS1-casein breakdown was of a similar magnitude to that found for varying levels of coagulant, the strong correlations (r2 = +0·800, −0·914 and −0·651) between αS1-casein breakdown and changes in curdiness, stickiness and smoothness with time do not fully explain the increase in smoothness and decrease in curdiness with increasing set-to-cut time. However, increasing the set-to-cut time from 30 to 50 min significantly (P < 0·1) increased the cheese moisture content and significantly (P < 0·001 to P < 0·1) reduced the cheese salt content, the pH and the calcium level. Consequently, cheese texture is determined primarily by its pH and chemical composition. Subsequent, early changes in texture are determined by αS1-casein breakdown. Downgrading for body defects such as curdiness at 35 days does not accurately predict what the cheese texture will be after (6 months) storage. The results of this work have shown that the body of a cheese can be singled out from others on the basis of a curdy texture at 1 month, but is indistinguishable at 6 months.

Milk-Clotting Enzymes. 1. Proteolysis During Cheese Making in Relation to Estimated Losses of Yield

Cheddar cheese was made in beakers (by the process for aged cheese) to compare milkclotting enzymes for their effect on proteolysis during coagulation, cooking, and cheddaring. All enzymes released more N into whey during cooking and cheddaring than calf rennet except the equal mixture of calf rennet and swine pepsin during cheddaring. Levels of true protein were the same in whey during cooking and during cheddaring with all enzymes, except those from Bacillus polymyxa showed proteolysis of whey proteins. Hydrolysis of casein occurred after cooking and during cheddaring with all enzymes including calf rennet. Data were discussed with respect to protein recoveries in cheese from ultrafiltered milk.Probable reductions in yield were estimated using a factor of 27.06 for converting estimated casein reductions in milk to percentage of yield losses. This factor assumes: the prices of milk fat and cheese are equal; cheddar cheese of the same composition is made of .37 moisture and .017 salt; whey contained .065 fat-free, curd-free solids; milk contained .036 fat and .ON64 casein or was standardid to the same casein:fat ratio, considering casein losses; and yield of cheese was 9.834 kg100kg milk. Yield losses (± least significant differences), compared with losses of calf rennet, were estimated as: bovine pepsin, –.14 (± .08); equal mixture of calf rennet and swine pepsin, –.07 (± .08); Mucor pusillus, –.49 (± .11); M. miehei (preparation I), –.63 (± .11); M. miehei, (preparation II), –.68 (± .12); Endothia parasitica, –1.24 (± .32); B. polymyxa, 4.79% (± .32%). These would be economically important losses of concern to cheese makers.Special attention was given to replications and statistical analyses to reduce least significant differences: quadruplicate Kjeldahl analyses, 6 to 12 replicate trials per enzyme, with comparison among enzymes within days.Comparison of levels of N in whey during simulated cheese making in beakers is suggested for comparing milk-clotting enzymes for their effect on yield of different varieties of cheese. This could be considered a basic loss of yield; losses of curd and fat in whey would be additional losses.

Dietary Restriction, Tyramine, and the Use of Monoamine Oxidase Inhibitors

The aim of this study is to provide clearer guidelines for rational, safe, and practical dietary restriction for use with monoamine oxidase inhibitors. Tyramine levels were assayed in over 100 of the controversial foods that have been associated with hypertensive reactions or reported to contain high levels of tyramine. Only a very limited number of foods appear to require absolute restriction. These include all aged cheeses, concentrated yeast extracts (e.g., Marmite), sauerkraut, and broad bean pods. Alcoholic beverages, including Chianti wine consumed in moderation, appear to be safe. Some aged meats contain relatively high levels of tyramine and require closer investigation.

Evaluation of Milk for Cheese Production Based on Milk Characteristics and Formagraph Measures

The characteristics of milk, including its clotting ability, were considered in an effort to develop an equation to predict yield of aged Parmesan cheese. The clotting properties of milk were measured using the Formagraph on 279 milk samples from the vats of 12 cheese plants over 12 mo. A significant, nonlinear relationship was found between the Formagraph measure of curd firmness and cheese yield. The relationship between predicted cheese yield and curd firmness depended on fat level. Increasing curd firmness increased cheese yield only at the low fat level. Intermediate values of curd firmness predicted highest cheese yields for the intermediate fat level. At the high fat level, increasing curd firmness resulted in decreasing predicted cheese yields. Cheese yields increased with fat and protein level. It appears that the Formagraph measure of curd firmness is related to cheese yield as an indicator of casein aggregation properties of the milk. No other Formagraph measures were significantly associated with actual aged cheese yield.