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Critical review of water activities and microbiology of drying of meats.

The drying of meat is one of the least expensive and most effective ways to preserve meat. This article reviews the influence of intrinsic and extrinsic parameters of foods in relation to the drying of meat and the role of microbial activities in the drying and storage of meat. The critical role of water activity and its relationship with other physical and chemical parameters and microbial survival in the drying of meat is also reviewed in detail. This article ends with a description of the various methods to measure water activity in foods. The conclusion is that the drying of meat is a highly complex phenomenon which is influenced by the composition of meat, its water holding capacity, the processing of meat, and various microorganisms found on meat before and after the drying process. There is no doubt that the drying of meat is an effective preservation process, but attention should be placed on the possible survival of microorganisms in the process in order to prevent spoilage and food-borne diseases.

Animals↗

The CYP1A1 genotype may alter the association of meat consumption patterns and preparation with the risk of colorectal cancer in men and women.

We hypothesized that the risk of colorectal cancer associated with meat preparation methods producing heterocyclic amines or polycyclic aromatic hydrocarbons is modified by the CYP1A1 genotype alone or in combination with the GSTM1 genotype or the NAT2 imputed phenotype. A total of 952 rectal cancer cases and 1205 controls (between September 1997 and February 2002) and 1346 colon cancer cases and 1544 controls (between October 1991 and September 1994) from Utah and Northern California were recruited from a population-based case-control study. Detailed interviews ascertained lifestyle, medical history, and diet and we extracted DNA from whole blood. Risk of colorectal cancer decreased among men with the CYP1A1 *2 any variant genotype and the lowest intake of poultry and men and women with high use of white meat drippings. Risk increased among men with the CYP1A1 *1 (no variant) allele and high white meat mutagen index, but decreased among those with the CYP1A1 *2 genotype. Risk increased with a high white meat mutagen index among women with the CYP1A1 *2 genotype and the GSTM1 present genotype. Risk of colorectal cancer decreased with the CYP1A1 *2 genotype, the NAT2 slow phenotype, and the use of white meat or its drippings. The association of risk for colorectal cancer and selected red and white meat mutagen indices and the use of white meat drippings, or fried white meat variables was more evident within select combinations of the CYP1A1 genotype and either the GSTM1 genotype or NAT2 than with the CYP1A1 alone. Genetic susceptibility may modify the associations of some meat or meat preparation factors with the risk of colorectal cancer.

Animals↗

Effects of crating and transport on stress and meat quality characteristics in broilers.

Experiments were conducted to determine 1) whether different crating durations influence stress responses and meat quality in broilers, and 2) whether holding crated broilers after transport influences corticosterone (CORT) levels and meat quality. In a preliminary experiment, male broilers (n = 50) were held in crates (10 birds per crate) for either 0, 1, 2, 3, or 4 h prior to processing. Crating duration did not affect plasma CORT level, cooking loss, shear value of breast or thigh muscles, or carcass skin discolorations. Crating duration also did not affect the color (L*, a*, b*, chroma, and hue angle) of breast meat, but did change the color of thigh meat, with samples from the 3 h crating group having the highest hue values (P < 0.01). Corticosterone concentrations and hue values of thigh samples were positively correlated (P < 0.05, r = 0.244). In Experiment 1, broilers (n = 36) were crated for either 1 or 3 h, with 9 birds per crate. Crating time did not influence plasma CORT, epinephrine, or norepinephrine concentrations, initial pH, color, or texture of breast and thigh meat samples. In Experiment 2, broilers were crated (nine birds per crate) early in the morning and transported 3 h to the processing facility by truck. Nine crates of birds were held in a dark quiet place for 4 h prior to processing (H) and the remaining nine crates were processed immediately (NH). Corticosterone levels were significantly lower (P < 0.01) in the H group than in the NH group. Initial pH of thigh meat of the H group was also significantly lower (P < 0.01), although breast meat pH was not affected by treatment. Holding had no effect on shear values, color (breast and thigh), or total heme concentration (thigh). There was a significant correlation (P < 0.01, r = 0.302) between CORT levels and hue values of thigh meat. These results suggest that higher preslaughter stress levels in broilers could influence the color of thigh meat, although overall meat quality was not affected under the conditions of this study.

Analysis of Variance↗

Thermal inactivation of Salmonella and Listeria monocytogenes in ground chicken thigh/leg meat and skin.

Thermal inactivation D and z values of Salmonella and Listeria monocytogenes were obtained for chicken thigh and leg meat and skin. The D values of Salmonella at 55 to 70 degrees C were 43.33 to 0.07 min in the meat and 43.76 to 0.09 min in the skin. The D values of L. monocytogenes at 55 to 70 degrees C were 38.94 to 0.04 min in the meat and 34.05 to 0.05 min in the skin. The z value of Salmonella was 5.34 degrees C in the meat and 5.56 degrees C in the skin. The z value of L. monocytogenes was 5.08 degrees C in the meat and 5.27 degrees C in the skin. For Salmonella or L. monocytogenes, the z value of the meat was not different from that of skin. However, the z value of Salmonella in meat or skin was different from that of L. monocytogenes in meat or skin. The z value of Salmonella or L. monocytogenes in chicken thigh and leg meat was different from that in the skin. The results from this study are useful for predicting process lethality of Salmonella and L. monocytogenes in products that contain chicken thigh and leg meat or skin.

Animals↗

Meat consumption is positively associated with psychomotor outcome in children up to 24 months of age.

OBJECTIVE: The impact of specific complementary foods on health outcomes has been poorly studied. We aimed to determine if meat consumption and breastfeeding influence growth and neurocognitive outcome in infants up to 24 months of age. METHODS: In a longitudinal cohort study, 144 full-term infants were recruited at 4 months. Their red and white meat consumption was recorded in sequential 7-day weighed food intake diaries at 4, 8, 12, 16, 20 and 24 months. Growth data were collected at the same census points as the dietary data. Neurocognitive outcome (psychomotor developmental indices and mental developmental indices) derived from the Bayley Scales of Infant Development II was measured at 22 months. RESULTS: Meat intake from 4-12 months was positively and significantly related to weight gain (P < 0.05); further analysis suggested this association might be mediated via protein intake but was independent of energy, zinc or iron intake. There was no interaction between meat intake and breastfeeding on growth. Meat intake from 4-12 and 4-16 months was positively and significantly related to psychomotor developmental indices (P < 0.02 and 0.013, respectively) but there was no association between breastfeeding and psychomotor developmental indices nor any interaction between meat intake and breastfeeding. Conversely, breastfeeding was positively and significantly related to mental developmental indices (P < 0.01) but there was no association between meat intake and mental developmental indices nor any interaction between breastfeeding and meat intake. These findings remained after adjustment for potential confounding factors. CONCLUSION: Meat intake, possibly via its effect on protein intake, is associated with increased weight gain in infants up to 12 months of age. Meat intake is also positively associated with psychomotor development at 22 months. These findings highlight the need for further investigation of the role of complementary foods in relation to health outcomes.

Breast Feeding↗

Role of nitric oxide in the renal hemodynamic response to a meat meal.

Ingestion of a high-protein meat meal results in significant increases in renal plasma flow (RPF) and glomerular filtration rate (GFR). The mechanism involved in this hemodynamic response to the meat meal has not yet been fully elucidated. The present study was designed to test the hypothesis that nitric oxide (NO) is involved in the renal hyperemic responses to a meat meal. To test this hypothesis, renal hemodynamic response to a meat meal (10 g/kg) was determined in conscious, chronically instrumented dogs with (n = 9) and without (n = 7) an intrarenal NO synthesis inhibition with NG-nitro-L-arginine methyl ester (L-NAME, 3 micrograms.kg-1.min-1 intrarenally). Under control conditions, the meat meal resulted in significant renal hyperemia. Three hours after ingestion of the meat meal, GFR (43 +/- 3 to 59 +/- 6 ml/min) and RPF (128 +/- 10 to 160 +/- 17 ml/min) progressively increased by approximately 40 and 25%, respectively. In contrast, pretreatment with intrarenal infusion of L-NAME abolished the GFR (48 +/- 6 to 52 +/- 6 ml/min) and RPF (129 +/- 20 to 121 +/- 17 ml/min) increases induced by the meat meal. Pretreatment with L-arginine (0.5 mg.kg-1.min-1) plus L-NAME (3 micrograms.kg-1.min-1) did not modify the meat meal-induced changes in GFR (41 +/- 4 to 66 +/- 6 ml/min) and RPF (127 +/- 9 to 182 +/- 14 ml/min). In summary, a meat meal in dogs results in marked increases in RPF and GFR. Intrarenal NO synthesis inhibition abolished the RPF and GFR responses to the meat meal.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Childhood cancer in relation to cured meat intake: review of the epidemiological evidence.

Over the past two decades a series of epidemiological studies have examined the relationship between consumption of cured meats during pregnancy and the subsequent risk of brain tumors, as well as other cancers, in the offspring. The research was prompted in large part by experimental investigations showing that transplacental exposure to certain N-nitroso compounds, i.e., nitrosoureas, could produce brain tumors in laboratory animals. Fourteen such epidemiological studies, 13 of which used the case-control approach, are reviewed here. Most of the studies showed no significant association between total cured meat intake and childhood cancer risk but more found positive than negative relationships. Furthermore, several studies reported significant positive associations for maternal and sometimes childhood or paternal consumption of one or more cured meats, with odds ratios of twofold or greater reported among the highest consumers. On the other hand, a correlation analysis found no positive concordance between temporal trends from the 1970s to 1990s in childhood brain cancer rates and cured meat consumption, inasmuch as cancer rates rose over time while residual nitrite levels in cured meats fell sharply. Because of the potential for bias, especially recall bias, and/or confounding, the relatively weak magnitude of the associations reported, and the inconsistency between study findings, at this time it cannot be concluded that eating cured meat has increased the risk of childhood brain cancer or any other cancers. Moreover, although N-nitroso compounds are sometimes found in cured meats or may be formed endogenously, there is no empirical evidence that eating cured meats results in human neural nitrosourea exposure. Nevertheless, the hypothesis that eating nitrite-cured meats may influence childhood and perhaps adult brain cancer cannot be dismissed. Unbiased evaluation of the hypothesis may derive from the conduct of cohort studies, where the interview-derived information on cured meat intake precedes, or is not otherwise associated with, the diagnosis of cancer.

Brain Neoplasms↗

Meat consumption and risk of stomach cancer in Uruguay: a case-control study.

We previously reported an association between meat intake and stomach cancer in Uruguay: in that analysis, we did not control for total energy intake. To better study the relationship between intake of meat and meat constituents and gastric cancer, we conducted a further case-control study including 123 cases and 282 controls who were enrolled between September 1997 and August 1999. Total meat intake (highest tertile) was associated with an odds ratio (OR) of 4.6 [95% confidence interval (CI) = 2.3-9.0]. After adjustment for total energy intake and intake of proteins and total fat by the residuals method, the OR was 1.7 (95% CI = 0.7-4.0). The energy-adjusted OR for high intake of processed meat was 1.9 (95% CI = 1.1-3.5). Intake of fried, barbecued, and salted meat and 2-amino-1-methyl-6-phenyl-imidazo[4,5-b]pyridine was not associated with risk of gastric cancer. The energy-adjusted OR of high intake of nitrosodimethylamine was 1.5 (95% CI = 0.9-2.8). These results suggest that, in a country with elevated meat consumption, total energy intake and intake of proteins and fat are powerful confounders in the relationship between meat intake and gastric cancer risk. However, a modest independent effect of meat, in particular of processed meat, is suggested.

Adult↗

Prevalence of viable Toxoplasma gondii in beef, chicken, and pork from retail meat stores in the United States: risk assessment to consumers.

The prevalence of viable Toxoplasma gondii was determined in 6,282 samples (2,094 each of beef, chicken, and pork) obtained from 698 retail meat stores from 28 major geographic areas of the United States. Each sample consisted of a minimum of 1 kg of meat purchased from the retail meat case. To detect viable T. gondii, meat samples were fed to T. gondii-free cats and feces of cats were examined for oocyst shedding. Initially, 100 g of meat from 6 individual samples of a given species were pooled (total, 600 g), fed to a cat over a period of 3 days, and feces were examined for oocysts for 14 days; the remaining meat samples were stored at 4 C for 14 days (until results of the initial cat fecal examination were known). When a cat fed pooled samples had shed oocysts, 6 individual meat samples from each pool were bioassayed for T. gondii in cats and mice. Toxoplasma gondii isolates were then genetically characterized using the SAG2 locus and 5 hypervariable microsatellite loci. In all, 7 cats fed pooled pork samples shed oocysts. Toxoplasma gondii oocysts were detected microscopically in the feces of 2 of the cats; 1 isolate was Type II and the second was Type III. Analyzed individually, T. gondii was detected by bioassay in 3 of the 12 associated samples with genetic data indicating T. gondii isolates present in 2. The remaining 5 pooled pork samples had so few oocysts that they were not initially detected by microscopic examination, but rather by mouse bioassay of cat feces. Two were Type I, 1 was Type II, and 2 were Type III. None of the cats fed chicken or beef samples shed oocysts. Overall, the prevalence of viable T. gondii in retail meat was very low. Nevertheless, consumers, especially pregnant women, should be aware that they can acquire T. gondii infection from ingestion of undercooked meat, and in particular, pork. Cooking meat to an internal temperature of 66 C kills T. gondii.

Animals↗

Performance of dairy goats fed soybean meal or meat and bone meal with or without urea during early lactation.

Use of meat and bone meal for early lactation rations was studied. In Experiment 1, 18 Alpine goats were used in a 15-wk lactation trial. Isonitrogenous and isoenergetic diets were fed (15% CP and 2.3 Mcal/kg metabolizable energy) containing soybean meal, meat and bone meal with urea, or meat and bone meal without urea. Dry matter intake was 2.21, 2.30, and 2.34 kg/d for does fed soybean meal, meat and bone meal with urea, and meat and bone meal without urea, respectively. Milk production was 2.50, 2.67, and 2.66 kg/d in the same sequence. Rumen ammonia N (mg/dl) and total VFA (mM) were 12.9 and 81.5, 21.4 and 76.3, and 12.2 and 81.6 for does fed soybean meal, meat and bone meal with urea, and meat and bone meal, respectively. Serum urea N was higher in does fed meat and bone meal with urea, and no differences were observed in serum total protein and plasma glucose concentrations. In Experiment 2, 4 mature, castrated male goats were used to estimate digestibilities and retention of nutrients in three diets. Digestibilities of NDF and P and retention of P were higher in goats fed the meat and bone meal diet. Allowance of absorbed protein for milk production was calculated to be 81 to 83 g/kg 4% FCM. Meat and bone meal may be utilized efficiently by lactating does as a protein less degradable in the rumen, Ca, and P source; and may be beneficial for higher milk production during early lactation.

Animal Feed↗

Quality characteristics of fresh blue crab meat held at 0 and 4 degrees C in tamper-evident containers.

There has been a regulatory movement toward the required use of tamper-evident containers for fresh blue crab meat. North Carolina passed tamper-evident regulations in 1993. Blue crab processors had little information on possible changes in head-space gases, microbial growth, chemical decomposition, sensory quality, or shelf life caused by the new containers. Chemical, microbiological, physical, and sensory changes in fresh crab meat were monitored during 18 days of storage in ice and 13 days of storage refrigerated at 4 degrees C. "Special" blue crab meat, chosen for the study, is the least expensive commercial form of white crab meat. The crab meat was packaged in four retail containers: copolymer polyethylene cups with polyethylene snap-on lids, copolymer polyethylene cups with snap-on polyethylene lids fastened to the cup with heat-shrink low-density polypropylene seals, copolymer polyethylene cans with aluminum easy-open ends, and copolymer polypropylene cups with a tamper-evident pull-tab on the lid. Control samples packaged in industry standard copolymer polyethylene cups maintained higher oxygen levels than meat stored in tamper-evident containers. No consistent differences in quality or shelf life were detected among the containers. Market shelf life was limited to 6 days for meat held at 4 degrees C and 15 days for meat held at 0 degrees C. Sensory quality deteriorated 6 days earlier for crab meat held at 4 degrees C than meat held at 0 degrees C. Collateral work showed that toxin production by Clostridium botulinum neither occurred following 18 days of storage at 4 degrees C nor after 15 days of storage at 10 degrees C. Definite spoilage occurred before any toxin production. The study suggests that blue crab processors can safely use the new tamper-evident packaging, which has little or no effect on product quality or shelf life. Processors may choose appropriate packaging options using price, packaging quality, market appearance, and ease of production as the deciding criteria.

Animals↗

Effects of wearing knitted or rubber gloves on the transfer of Escherichia cohi between hands and meat.

On eight occasions, five volunteers each handled five pieces of meat with bare hands or while wearing dry or wet knitted gloves or rubber gloves after hands had been inoculated with Escherichia coli or after handling a piece of meat inoculated with E. coli. On each occasion, after all meat was handled, each piece of meat, glove, and hand were sampled to recover E. coli. When hands were inoculated, E. coli was recovered from all meat handled with bare hands, in lesser numbers from some pieces handled with knitted gloves, and from only one piece handled with rubber gloves. When pieces of inoculated meat were handled, the numbers of E. coli transferred to uninoculated meat from bare hands or rubber gloves decreased substantially with each successive piece of uninoculated meat, but decreases were small with knitted gloves. The findings indicate that, compared with bare hands, the use of knitted gloves could reduce the transfer of bacteria from hands to meat but could increase the transfer of bacteria between meat pieces, whereas the use of rubber gloves could largely prevent the first and greatly reduce the second type of bacteria transfer.

Bacterial Adhesion↗

Consumption, knowledge, and handling of raw meat: a representative cross-sectional survey in Germany, March 2001.

Outbreaks of gastroenteritis have been repeatedly associated with the consumption of raw meat and raw meat products. To assess the potential of this problem in Germany, frequency of consumption and knowledge about and handling of raw meat during food preparation in the German population was estimated. We conducted a population-based nationwide cross-sectional survey in private households in March 2001 by random telephone numbers. Consenting German-speaking persons were randomly chosen among household members for standardized interviews. Proportions were standardized by age, sex, and region (eastern and western Germany). A total of 510 people were interviewed (response 45.1%), including 62.3% women and 31.8% considered at high risk (children younger than 10 years old, elderly more than 65 years old, and chronically ill persons). The mean age was 45.7 years. Of those who ate raw ground meat at least once a week, 17.8% lived in eastern Germany and 5.1% in western Germany, (chi-square test, P < 0.001). Teewurst was eaten by 50.8% of all respondents and 53.8% of respondents in the high-risk group. That salami or Teewurst were raw meat products was known to 58.1 and 36.3% of the respondents, respectively. Respondents reported not washing their hands (46.6%) or cleaning their cutting boards with soap (48.1%) after preparing raw meat. A total of 10.3% of the respondents had diarrhea during the last 3 months. Although knowledge is poor, consumption of raw meat products is widespread in Germany, even among high-risk persons. More information is necessary on which products contain raw meat, the potential risk of diarrhea after raw meat products are consumed, and appropriate handling of raw meat products.

Adolescent↗

Combined effects of well-done red meat, smoking, and rapid N-acetyltransferase 2 and CYP1A2 phenotypes in increasing colorectal cancer risk.

Heterocyclic amines (HAAs) are suspected carcinogens that are formed in meat when it is cooked at high temperature for long durations. These compounds require metabolic activation by CYP1A2 and N-acetyltransferase (NAT) 2 or NAT1 before they can bind to DNA. It has been hypothesized that well-done meat increases the risk of colorectal cancer (CRC), especially in individuals with the rapid phenotype for CYP1A2 and NAT2. This association may be particularly strong in smokers because smoking is known to induce CYP1A2. We conducted a population-based case-control study on Oahu, Hawaii to specifically test this hypothesis. An in-person interview assessed the diet and preference for well-done red meat of 349 patients with CRC and 467 population controls. A urine collection after caffeine challenge and a blood collection were used to assess phenotype for CYP1A2 and NAT2 and genotype for NAT2 and NAT1, respectively. No statistically significant main effect association with CRC was found for red meat intake, preference for well-done red meat, the NAT2 rapid genotype, the CYP1A2 rapid phenotype or the NAT1*10 allele. However, in ever-smokers, preference for well-done red meat was associated with an 8.8-fold increased risk of CRC (95% confidence interval, 1.7-44.9) among subjects with the NAT2 and CYP1A2 rapid phenotypes, compared with smokers with low NAT2 and CYP1A2 activities who preferred their red meat rare or medium. No similar association was found in never-smokers, and there was no increased risk for well-done meat among smokers with a rapid phenotype for only one of these enzymes or for smokers with both rapid phenotypes who did not prefer their red meat well-done. These data provide additional support to the hypothesis that exposure to carcinogens (presumably HAAs) through consumption of well-done meat increases the risk of CRC, particularly in individuals who are genetically susceptible (as determined by a rapid phenotype for both NAT2 and CYP1A2) and suggest that smoking, by inducing CYP1A2, facilitates this effect.

Aged↗

A common-source outbreak of trichinosis from consumption of bear meat.

This paper discusses an outbreak of trichinosis that occurred in 1998 in Montgomery County, Ohio, and the investigation that followed. The outbreak was associated with consumption of bear meat from a hunt in Ontario, Canada. The person who had the index case had eaten two bear burgers that were cooked rare in a microwave oven. Bear meat from the same hunt later was consumed by 15 other people at a church supper and an additional 13 people who did not attend the supper. Of the 15 attendees at the church supper who ate the bear meat, seven developed illness consistent with Trichinella infection (attack rate about 47 percent). An additional seven people attended the supper but did not eat the bear meat and did not become ill. Having eaten bear meat at the church supper was associated with an increased risk of illness (p = .05). Inadequate cooking of the bear meat resulted in the transmission of live trichinae. The 13 other people who ate the bear meat but did not attend the supper reported no illness. A total of eight people, including the person with the index case, met the case definition for trichinosis. Adequate cooking of the bear meat or consumption of uninfected portions of the meat was probably the protective factor for those who did not become ill after consuming the bear meat.

Adult↗

A prospective cohort study on the relation between meat consumption and the risk of colon cancer.

The high incidence of colon cancer in affluent societies has often been attributed to a high fat diet and, more in particular, the consumption of meat. The association of the consumption of meat and the intake of fat with risk of colon cancer was investigated in a prospective cohort study on diet and cancer, which is being conducted in the Netherlands since 1986 among 120,852 men and women, aged 55-69. The analysis was based on 215 incident cases of colon cancer (105 men and 110 women) accumulated in 3.3 years of follow-up, excluding cases diagnosed in the first year of follow-up. Dietary habits were assessed at baseline with a 150-item semiquantitative food frequency questionnaire. No trends in relative rates of colon cancer were detected for intake of energy or for the energy-adjusted intake of fats, protein, fat from meat, and protein from meat. Consumption of total fresh meat, beef, pork, minced meat, chicken, and fish was not associated with risk of colon cancer either. Processed meats, however, were associated with an increased risk in men and women (relative rate, 1.17 per increment of 15 g/day; 95% confidence interval, 1.03-1.33). The increased risk appeared to be attributable to one of the five questionnaire items on processed meat, which comprised mainly sausages. This study does not support a role of fresh meat and dietary fat in the etiology of colon cancer in this population. As an exception, some processed meats may increase the risk, but the mechanism is not yet clear.

Age Factors↗

Motivation and characterization of finnish meat inspection veterinarians.

A questionnaire survey on the factors affecting the motivation and work attitudes of Finnish veterinary meat inspectors was conducted. Traditional meat inspection on the slaughtering line and in the emergency department took up most of the weekly work time (15.8% and 15.8%, respectively). Emergency slaughtering (29%) and general hygiene control (29%) were considered the most important tasks of veterinary meat inspectors. Assurance of meat safety (68%) was cited as the most important single reason for meat inspection. Veterinary meat inspectors were of the opinion that they do not play an important role in the training of slaughterhouse personnel, although they considered training to be a very important means for promoting hygienic work methods among workers. Three orientations of the respondents toward meat inspection and slaughterhouse operations were revealed from the survey: hygiene, education, and emergency slaughter work orientation. Meat inspection veterinarians may feel isolated from the other personnel responsible for maintaining quality and hygiene. The orientation and possible isolated position of veterinary meat inspectors should be given more attention in both the basic undergraduate and postgraduate training of veterinary meat inspectors.

Abattoirs↗

Conjugated linoleic acid (CLA) versus saturated fats/cholesterol: their proportion in fatty and lean meats may affect the risk of developing colon cancer.

In spite of the considerable amount of experimental, clinical and epidemiological research about the consumption of red meat, total fats, saturated/unsaturated fatty acids and cholesterol with regard to the risk of developing colorectal cancer (CRC), the issue remains controversial. The general belief is a reduction of red meat intake, and subsequent nutritional advice usually strongly recommends this. Paradoxically, beef together with whole milk and dairy derivatives, are almost the only sources for conjugated linoleic acid (CLAs) family. Furthermore CLAs are the only natural fatty acids accepted by the National Academy of Sciences of USA as exhibiting consistent antitumor properties at levels as low as 0.25-1.0 per cent of total fats. Beside CLA, other polyunsaturated fatty acids (PUFA) belonging to the essential fatty acid (EFA) n-3 family, whose main source are fish and seafood, are generally believed to be antipromoters for several cancers. The purpose of this work is to critically analyze the epidemiological and experimental evidence by tentatively assuming that the reciprocal proportions of saturated fats (SA) plus cholesterol (CH) versus CLAs levels in fatty or lean beef may play an antagonistic role underlying the contradictory effects reported for red meats consumption and CRC risk. Recent results about meat intake and risk for CRC in Argentina have shown an unexpected dual behaviour related to the type of meats. Fatty meat derivatives, such as cold cuts and sausages, mainly prepared from fatty beef (up to 37% fat) were associated with higher risk, whereas high consumption of lean beef (< 15% fat) behaved as a protective dietary habit. CLA is located in the interstitial, non-visible, fat evenly distributed along muscle fibres as well as in subcutaneous depots. Visible fat may be easily discarded during the meal, whereas interstitial fats will be eaten. The remaining intramuscular fat in lean meats range from 25 to 50 g/Kg (2.5 to 5%). The proportion of CLA/SA+CH for lean beef eaters is 0.09 and the fatty meats 0.007 (g/100 g). As a consequence, the beneficial effects of minor amounts of CLA may be relatively enhanced in lean meat compared to fatty meat sub-products which contain a substantial amount of saturated fatty acids and cholesterol, as in cold cuts and cow viscera.

Journal Article↗