FROZEN RAW FOODS AS SKIN-TESTING MATERIALS—Further Studies of Use in Cases of Allergic Disorders

In further studies on the use of frozen raw food as skin-testing material in patients with allergic disorders, the results of previous work were confirmed in a greater number of subjects using a larger number of foods:Tests with frozen raw foods by the scratch method induce true positive reactions of a larger size and in greater frequency than the corresponding commercial extracts by either the scratch or the intracutaneous method.Storage in the frozen state for several years does not affect the antigenic potency of the materials. The frozen preparations have caused no harmful effects in the subjects, are free from irritant properties, and are not urticariogenic.     

Questions and Answers about C. P. S

Frozen foods for skin testing were prepared, stored and used by a simple, practicable, and inexpensive method. The capacity of raw foods to produce immunologically positive skin reactions by the scratch test method was reaffirmed. Storage in the frozen state for several months and thawing immediately before using for one series of tests did not affect the allergenic properties of the material. Raw foods were found to be innocuous to the skin and non-urticariogenic in allergic as well as in non-allergic persons. Raw foods, by the scratch test method, induced true positive reactions of a larger size and in greater numbers than the corresponding commercial extracts in the same series of subjects tested.     

Questions and Answers about C. P. S

Frozen foods for skin testing were prepared, stored and used by a simple, practicable, and inexpensive method.The capacity of raw foods to produce immunologically positive skin reactions by the scratch test method was reaffirmed.Storage in the frozen state for several months and thawing immediately before using for one series of tests did not affect the allergenic properties of the material.Raw foods were found to be innocuous to the skin and non-urticariogenic in allergic as well as in non-allergic persons.Raw foods, by the scratch test method, induced true positive reactions of a larger size and in greater numbers than the corresponding commercial extracts in the same series of subjects tested.     

Repair and Enumeration of Injured Coliforms in Frozen Foods

Two strains of Escherichia coli manifested death and repairable injury after being frozen in water or sterile foods at -20 C. The injured survivors were inhibited from forming colonies on violet red bile agar (VRBA) or deoxycholate lactose agar; this inhibition was greater when enumeration was done by the pour plate method instead of the surface or surface-overlay method. Injured cells repaired rapidly in Trypticase soy broth (TSB), and the repair was about maximum after 1 h at 25 C. When the injured cells were added to different foods and incubated at 25 C, repair also occurred; however, recovery was better and more uniform when the samples were mixed with TSB and incubated 1 h at 25 C. Cell multiplication was not evident until after 90 to 120 min at 25 C. The enumeration of coliforms from commercially frozen foods was increased when the thawed samples were mixed with TSB and the cells were allowed to repair 1 h at 25 C. In some samples, the repair permitted at least a 20-fold increase in the coliform count. The associated flora in the commercially frozen foods gave no evidence of impairing the repair of coliforms, nor did they start multiplication prior to 90 min after being incubated in TSB at 25 C. Generally, the plating gave more reproducible recovery of coliforms than did the most probable number method. Also, a higher number of coliforms were obtained by the surface-overlay method of plating using VRBA.     

2020年湖北省襄阳市601份冷冻食品新冠肺炎病毒检测结果分析

自新冠疫情暴发以来,食品或其包装袋不断被检测出新型冠状病毒(SARS-CoV-2)核酸阳性,均与冷冻生鲜相关。为评估SARS-CoV-2污染冷冻食品的风险,本研究采集湖北省襄阳市各大商超、批发市场和餐饮企业的601批次冷冻食品进行新型冠状病毒核酸检测,分析国内外不同品种和不同经营场所的冷冻食品的新型冠状病毒核酸检测结果。结果显示,该601批次的冷冻食品的新型冠状病毒核酸检测结果全部为阴性。本研究提示,襄阳市的冷冻食品被SARS-CoV-2污染的风险较低,其作为SARS-CoV-2传染源的可能性较小。     

The impact of oral health on stated ability to eat certain foods; findings from the National Diet and Nutrition Survey of Older People in Great Britain

Objectives. To assess how the dental status of older people's mouths affected their stated ability to eat common foods. Design. Cross sectional study. Subjects. Survey was part of the oral health component of the nationwide British National Diet and Nutrition Survey: people aged 65 years and older. Two separate representative samples aged 65 and over: a free-living and an institutional sample. 881 free-living and 275 institution subjects had a dental exam and were interviewed about ability to eat key foods. Results. Significant percentages of free-living people had difficulty or could not eat at least 4 of 16 foods, and about 1 in 5 dentate stated they had difficulty eating or could not eat raw carrots, apples, well-done steak or nuts. More of the edentate subjects stated that they had difficulty eating than the dentate. Perceived chewing ability increased with increasing numbers of natural teeth and pairs of opposing posterior teeth. Subjects reporting a sociodental impact were more likely to consider that they were unable to eat foods that required more chewing. Associations remained valid after correction for the effects of age, sex, social class and denture wearing status and region. Perceived dryness did not affect significantly the stated ease of eating most foods. There were more dietary restrictions reported by the institution sample. Some foods, such as nuts, apples and raw carrots could not be eaten easily by over half of edentate people in the institution sample. Conclusions. The stated selection of foods are substantially affected by numbers of teeth and occluding pairs of posterior teeth and presence of full dentures in significant percentages of older people.     

Diet-Related Buccal Dental Microwear Patterns in Central African Pygmy Foragers and Bantu-Speaking Farmer and Pastoralist Populations

Pygmy hunter-gatherers from Central Africa have shared a network of socioeconomic interactions with non-Pygmy Bantu speakers since agropastoral lifestyle spread across sub-Saharan Africa. Ethnographic studies have reported that their diets differ in consumption of both animal proteins and starch grains. Hunted meat and gathered plant foods, especially underground storage organs (USOs), are dietary staples for pygmies. However, scarce information exists about forager–farmer interaction and the agricultural products used by pygmies. Since the effects of dietary preferences on teeth in modern and past pygmies remain unknown, we explored dietary history through quantitative analysis of buccal microwear on cheek teeth in well-documented Baka pygmies. We then determined if microwear patterns differ among other Pygmy groups (Aka, Mbuti, and Babongo) and between Bantu-speaking farmer and pastoralist populations from past centuries. The buccal dental microwear patterns of Pygmy hunter-gatherers and non-Pygmy Bantu pastoralists show lower scratch densities, indicative of diets more intensively based on nonabrasive foodstuffs, compared with Bantu farmers, who consume larger amounts of grit from stoneground foods. The Baka pygmies showed microwear patterns similar to those of ancient Aka and Mbuti, suggesting that the mechanical properties of their preferred diets have not significantly changed through time. In contrast, Babongo pygmies showed scratch densities and lengths similar to those of the farmers, consistent with sociocultural contacts and genetic factors. Our findings support that buccal microwear patterns predict dietary habits independent of ecological conditions and reflect the abrasive properties of preferred or fallback foods such as USOs, which may have contributed to the dietary specializations of ancient human populations.     

Comparison of Two Methods for the Isolation of Salmonellae From Imported Foods

Two methods for the detection of salmonellae in foods were compared in 179 imported meat and egg samples. The number of positive samples and replications, and the number of strains and kinds of serotypes were statistically comparable by both the direct enrichment method of the Food Hygiene Laboratory in England, and the pre-enrichment method devised for processed foods in the United States. Boneless frozen beef, veal, and horsemeat imported from five countries for consumption in England were found to have salmonellae present in 48 of 116 (41%) samples. Dried egg products imported from three countries were observed to have salmonellae in 10 of 63 (16%) samples. The high incidence of salmonellae isolated from imported foods illustrated the existence of an international health hazard resulting from the continuous introduction of exogenous strains of pathogenic microorganisms on a large scale.     

Incidence of Clostridium perfringens in American Foods

Food samples were examined for the presence of Clostridium perfringens. A medium described by Mossel and later modified by Angelotti et al. was used for the detection and enumeration of C. perfringens. The incidence of C. perfringens observed in the foods examined was 6.1%. C. perfringens was recovered from 2.7% of the commercially prepared frozen foods, 3.8% of fruits and vegetables, 5.0% of spices, 1.8% of home-prepared foods, and 16.4% of raw meat, poultry, and fish.     

A new direct plate method for the enumeration of Escherichia coli in frozen foods

H all , L.P. 1984. A new direct plate method for the enumeration of Escherichia coli in frozen foods. Journal of Applied Bacteriology 56 , 227–235.
A new method has been devised, incorporating a resuscitant stage, which allows direct isolation of Escherichia coli biotype I, Irregular type II and Irregular type VI. Rapid indole tests on the distinctive colonies produced enable determinations of E. coli biotype I to be made within 24 h. This method employs materials of low cost and achieves complete recovery of injured cells. It also detects not only anaerogenic strains but those which are slow in producing acid from lactose or give negative results by other methods. If required, further study of isolates can be made after the indole test. Comparisons were made between conventional methods, the new method and a similar direct plate method. The implications of the higher counts obtained by the two latter methods are discussed in relation to microbiological specifications and standards for frozen foods.     

Estimating energy intake of urban women in Colombia: Comparison of diet records and recalls

As part of a larger study of energy-nutrition, we compared the performance of 24 h diet recalls with estimated diet records kept by trained observers. The subjects were economically disadvantaged women (n = 85) in the city of Cali, Colombia. A 24 h recall and an estimated diet record were collected for each woman at 0 and approximately 3 and 6 months. Energy intake obtained from the estimated dietary records was validated against energy expenditure and used as the reference method. Energy and macronutrient intake were calculated from published food composition tables and proximate analyses of common foods. The number of food items consumed per woman per day, total and in each of 16 food groups, was tabulated. Energy and macronutrient intakes were 11–13% lower in the 24 h recalls. The discrepancy energy could be largely accounted for by the lower number of food items in the recalls. The number of food items in eight of 16 food groups was significantly lower in the recalls compared to the records. Underreporting on the recalls was a general tendency in these subjects and not clearly related to average energy intake. We conclude that 24 h diet recalls underestimate energy and nutrient intake in this population and are not suitable for studies of human energetics. Am J Phys Anthropol 108:53–63, 1999. © 1999 Wiley-Liss, Inc.     

Microcolony epifluorescence microscopy for selective enumeration of injured bacteria in frozen and heat-treated foods

A rapid (less than 6 h) method for selectively enumerating coliforms, pseudomonads, and staphylococci has been developed which involves counting microcolonies grown on the surface of polycarbonate membranes under selective conditions. The method was not directly applicable to foods containing injured bacteria due to the poor formation of or an inability to form microcolonies under selective conditions. However, the introduction of a 3- to 5-h resuscitation step in tryptone soya broth allowed the method to give reliable estimates of these organisms in a variety of frozen and heat-processed foods. Under nonselective conditions, i.e., for total counts, the microcolony method enabled a rapid count to be made of viable bacteria in heat-treated foods, but these results were also made more consistent by the introduction of a resuscitation step. This method makes results from these foods available far faster than conventional enumeration methods.     

Microcolony epifluorescence microscopy for selective enumeration of injured bacteria in frozen and heat-treated foods.

A rapid (less than 6 h) method for selectively enumerating coliforms, pseudomonads, and staphylococci has been developed which involves counting microcolonies grown on the surface of polycarbonate membranes under selective conditions. The method was not directly applicable to foods containing injured bacteria due to the poor formation of or an inability to form microcolonies under selective conditions. However, the introduction of a 3- to 5-h resuscitation step in tryptone soya broth allowed the method to give reliable estimates of these organisms in a variety of frozen and heat-processed foods. Under nonselective conditions, i.e., for total counts, the microcolony method enabled a rapid count to be made of viable bacteria in heat-treated foods, but these results were also made more consistent by the introduction of a resuscitation step. This method makes results from these foods available far faster than conventional enumeration methods.     

Great apes prefer cooked food

The cooking hypothesis proposes that a diet of cooked food was responsible for diverse morphological and behavioral changes in human evolution. However, it does not predict whether a preference for cooked food evolved before or after the control of fire. This question is important because the greater the preference shown by a raw-food-eating hominid for the properties present in cooked food, the more easily cooking should have been adopted following the control of fire. Here we use great apes to model food preferences by Paleolithic hominids. We conducted preference tests with various plant and animal foods to determine whether great apes prefer food items raw or cooked. We found that several populations of captive apes tended to prefer their food cooked, though with important exceptions. These results suggest that Paleolithic hominids would likewise have spontaneously preferred cooked food to raw, exapting a pre-existing preference for high-quality, easily chewed foods onto these cooked items. The results, therefore, challenge the hypothesis that the control of fire preceded cooking by a significant period.     

Food choice by older people: the use of semi-structured interviews with open and closed questions

Objective: To evaluate difficulty chewing, consequent food choice and impacts using both open and closed questions within a semi‐structured interview format. Design: A cross‐sectional study using a semi‐structured interview (SSI) with open and closed questions Setting: Independently living people in South‐West London interviewed in their own homes Subjects: A group of 54, edentate people (mean age 82, R= 60‐93 years) were studied. Results: Most subjects (69%) expressed difficulty eating at least one type of food, half were unwilling to eat the foods they found difficult, others were conscious of cooking longer or cutting smaller in order to manage these foods, although no one accepted that they overcooked food. There were dramatic differences in the number of subjects expressing difficulty to chew various foods when responding to open and closed questions. Roast beef proved a good discriminator in this group of predominantly English subjects. The importance of the questioning process was also shown by the discrepancy of responses between variously prepared apples and the inability of any subjects to bite an unpeeled apple. Conclusions: For sensitive appraisal of food choice it is obviously essential to assess relevant foods, for the culture of the group being studied. Open questions provide a way of exploring which are the appropriate foods and food preparation as criteria to assess perceived chewing ability and treatment benefit. The semi‐structured interview method is particularly valuable for the study of older people. Closed questions provide different information which is also necessary to secure recall by older people.     

Occurrence of mutagens in canned foods

Mutagens are shown to be present in a variety of commercially heat-processed foods. Since these substances are not present in the unheated raw material, it appears that they are produced during processing. Canned salmon and beef broth showed the highest mutagenicity while other canned beef and fish products yielded lower but detectable levels. These findings are significant not only because of the large proportion of the food supply which is processed by canning, but also because the mutagens in these foods exhibit chemical behaviors and Salmonella strain specificity similar to mutagens in grilled foods which have been shown to be mammalian carcinogens.     

Image analysis method for evaluation of specific and non-specific hand contamination

AIMS: To evaluate a quantifying image analysis method for assessing the degree of hand contamination and efficacy of hand washing procedures. METHODS AND RESULTS: Two types of experimental design were used. In one, different concentrations of pure cultures of Escherichia coli, Listeria innocua and Pseudomonas flourescens were applied to hands. In the other, hands were contaminated by handling various raw foods. Imprints of the contaminated palms were made on 24.5 x 24.5 cm agar plates using appropriate agars. After incubation, digital photographs of the plates were analysed using image analysis. In pure culture studies with selective agars, levels from 1 to 10(6) CFU cm(-2) palm could be monitored. For aerobic, mesophilic organisms from raw chicken, levels from 10(3) to 10(6) CFU cm(-2) palm were correlated linearly to image analysis data. CONCLUSIONS: The image analysis of palm imprints made on agar plates was suitable for assessing the degree of contamination from foods on the palms. Sensitivity and specificity depended on the agar used and the type of contamination encountered. SIGNIFICANCE AND IMPACT OF THE STUDY: Data capture by the image analysis method is simple and can be partly automated. Sampling time is short for the person to be tested, which makes it an attractive method for assessing hand hygiene status in larger field trials.     

乳酸菌的抗冷冻性及耐受机理

乳酸菌发酵剂在工业生产过程中,会受到冷冻的刺激,如真空冷冻干燥及后期的低温保藏,此外,发酵乳制品的保藏和干酪的成熟过程也都在低温中进行。这些均会对乳酸菌发酵剂及发酵乳制品质量产生一定的影响。因此,掌握乳酸菌在冷冻条件下的反应机理有助于优化发酵剂和发酵乳制品在工业生产中的冷冻、发酵和贮藏条件,从而提高产品质量和生产效益。本文对乳酸菌的抗冷冻性及机理进行了分析,并对发酵剂的保护提出具体措施。     

Histological Effect of Certain Pickles on the Human Gastric Mucos: A Preliminary Report

The histological effects of several types of pickles and control substances were assessed by repeated suction (per os) biopsies of the gastric antrum in three healthy men. The ingestion of 30 ounces of fukujinzuke (assorted vegetables pickled in soy sauce) or of vinegared gherkins over a three-day period caused marked changes in the surface epithelium and gastric pits in all three subjects. The abnormalities consisted of loss of cellular mucus, nuclear enlargement, prominent nuclear chromatin and an increased number of mitotic figures. All control biopsies were normal, as were biopsies after the ingestion of 30 ounces of raw carrots or cucumbers over a three-day period. This study shows that eating a sufficient quantity of certain types of pickles causes marked changes in the human stomach. Peroral suction biopsy of the gastric antrum appears to be a practical method for testing the effect of various foods on the human gastric mucosa.     

Effect of reproductive state and body size on food consumption in captive Galago senegalensis braccatus

Measurements of food consumption for different types of foods were made for seven Galago senegalensis braccatus. Differences because of reproductive state in females and body size were found. Lactating females consumed more food in total and had greater energy and protein intake than they did during other reproductive states. Near-term pregnant females consumed less food, energy, and protein than they did during other reproductive states. Body size affected food intake, with smaller animals ingesting more per unit metabolic weight than larger subjects.