Health Protection Branch Research Articles

Importance of Quality Assurance in Canadian Pesticide Analysis

Three important elements of the pesticide quality assurance program in the Health Protection Branch of Canada are described--the sampling protocol, the repository of pesticide standards, and the check sample program of the Federal Interdepartmental Committee on Pesticides. All play an important role in ensuring the production of sound, valid pesticide residue data. Efforts to improve each element will continue in the future.

Health Protection Branch Standards and Guidelines for Microbiological Safety and General Cleanliness of Food - An Overview (Part 2.)

Health Protection Branch Standards and Guidelines for Microbiological Safety and General Cleanliness of Food - An Overview (Part 2.)

Improved immunological membrane filter method for detection of food-borne Salmonella strains.

An improved membrane filter method that involves the use of an enzyme-labeled antibody stain has been developed for the rapid detection of Salmonella species in foods. The procedure is carried out directly on a hydrophobic grid-membrane filter without requiring transfer by blotting to nitrocellulose. Pure cultures of 54 Salmonella species and 10 foods artificially contaminated with Salmonella colindale gave a positive reaction in which Salmonella colonies were visible as purple dots. Of 11 nonsalmonella organisms, only Citrobacter freundii reacted with Spicer-Edwards antiserum. Of 22 naturally contaminated food samples, 10 were positive for both the hydrophobic grid-membrane filter procedure of the Association of Official Analytical Chemists and the improved enzyme-labeled antibody stain method, and there was perfect agreement between the methods. Of these 10 positive samples, one was negative by the Health Protection Branch method; of the negative samples, two were positive by this latter method. The improved enzyme-labeled antibody stain method allows detection of Salmonella spp. in foods within 48 h, requires little equipment, and is inexpensive, easy to perform, and suitable for automated detection.

The necessary minimal duration of final long-term toxicologic tests of drugs

The optimal, and thus mandatory duration of final, long-term toxicologic tests of drugs in animals prior to marketing for use in human beings remains controversial. Some regulatory authorities contend that exposure for 6 or 12 months is adequate. However, the Bureau of Human Prescription Drugs of the Health Protection Branch of Health and Welfare Canada has evaluated a number of confidential reports from manufacturers in which significant, non-neoplastic, pathologic changes occurred only after exposure of animals for more than 1 year. Fifteen examples from these files and the literature are described. These studies support the current Canadian guidelines' requirement for the duration of final long-term toxicologic tests of drugs to be at least 18 months.

Potential Use of Membrane Filters and a Fluoregenic Reagent-Based Solid Medium for the Enumeration of Escherichia coli in Foods

A direct plating method using as the medium buffered tryptone bile agar with 4-methylumbelliferyl-β-D-glucuronide added was evaluated for its ability to enumerate Escherichia coli at 44.5°C. The clarity of the result depended on the type of membrane filter used. The fluorescence observed from colonies growing on cellulose nitrate or mixed esters of cellulose was strong. Limited trials with food showed good recovery of E. coli when compared to the direct plating method based on indole production, of the Health Protection Branch (Method MFA-27). The method appears to be a simple, rapid, reliable alternative to the indole method for the enumeration of E. coli in foods.

Canadian Health Protection Branch Comments on Datascope Blood Pressure Monitors

Canadian Health Protection Branch Comments on Datascope Blood Pressure Monitors

Bacteriological Survey of Freshly Formed Cheddar Cheese

Two hundred-fifty freshly formed cheese samples produced by 32 provincially inspected cheese plants were analyzed by 7 regional laboratories of the Ontario Ministry of Health. Coliforms were detected in 61 (25.8%) and fecal coliforms confirmed in 46 (19.5%) of the 236 samples tested, with geometric mean counts per g of 133 and 136, respectively. The incidence of coliforms was highest in Cheddar cheeses made from pasteurized milk (29.7%) compared with the incidence of raw milk cheese (22.0%) and cheese made from milk which had been subjected to sub-pasteurization heat treatment (28.2%). Conversely, the incidence of fecal coliforms was lowest in pasteurized milk cheese (17.8%), followed by raw milk cheese (22.0%) and highest in heat-treated milk cheeses (25.6%). Staphylococcus aureus above the screening level of 1000 per g was not found in any of the 237 samples analyzed. Salmonella spp. were not detected in any of the 250 samples. These results suggest that producers of Cheddar cheese should have no difficulty in meeting the microbiological standards adopted by the Health Protection Branch, Health and Welfare Canada.

Efficacy of an International Method for Detection of Salmonella in Chocolate and Cocoa Products

The methods of the International Office of Cocoa and Chocolate and International Sugar Confectionery Manufacturers' Association (IOCC/ISCMA), and of the Health Protection Branch (HPB) were compared for their ability to detect Salmonella in chocolate and cocoa products. Of 152 samples tested, 13 contaminated samples were identified, 10 by the HPB and 8 by the IOCC/ISCMA method. Prolonged (48 h) incubation of enrichment media produced two false-negative results each with the Muller-Kauffman tetrathionate and the selenite cystine broths, exerted no effect on tetrathionate brilliant green, and identified one additional positive sample with the selenite brilliant green broth. More samples were found positive on bismuth sulfite than on brilliant green and brilliant green sulfa agar media. The present study underlines the limited sensitivity of both standard methods and questions the determinant role of casein in the neutralization of toxic agents in cocoa products.

Health & safety issues in computer graphics (Panel Session)

Health & safety issues in computer graphics (Panel Session)

Report of the Joint Mycotoxin Committee

Journal Article Report of the Joint Mycotoxin Committee Get access Peter Scott, Peter Scott Chairman Food Research Division, Health Protection Branch, Ottawa, Ontario, Canada K1A 0L2 Search for other works by this author on: Oxford Academic Google Scholar Other members: Other members: Search for other works by this author on: Oxford Academic Google Scholar Journal of Association of Official Analytical Chemists, Volume 65, Issue 2, 1 March 1982, Pages 411–412, https://doi.org/10.1093/jaoac/65.2.411 Published: 15 February 2020

Rapid detection of Salmonella spp. in food by use of the ISO-GRID hydrophobic grid membrane filter.

A rapid hydrophobic grid-membrane filter (HGMF) method was developed and compared with the Health Protection Branch cultural method for the detection of Salmonella spp. in 798 spiked samples and 265 naturally contaminated samples of food. With the HGMF method, Salmonella spp. were isolated from 618 of the spiked samples and 190 of the naturally contaminated samples. The conventional method recovered Salmonella spp. from 622 spiked samples and 204 unspiked samples. The isolation rates from Salmonella-positive samples for the two methods were not significantly different (94.6% overall for the HGMF method and 96.7% for the conventional approach), but the HGMF results were available in only 2 to 3 days after sample receipt compared with 3 to 4 days by the conventional method.

Report on Fungicides, Herbicides, and Plant Growth Regulators

Journal Article Report on Fungicides, Herbicides, and Plant Growth Regulators Get access W Harvey Newsome W Harvey Newsome Health and Welfare Canada, Food Research Division, Health Protection Branch, Ottawa, Ontario, Canada K1A 0L2 Search for other works by this author on: Oxford Academic Google Scholar Journal of Association of Official Analytical Chemists, Volume 64, Issue 2, 1 March 1981, Pages 394–395, https://doi.org/10.1093/jaoac/64.2.394 Published: 22 January 2020

Commercial production of125I-Fibrinogen injection

In 1975 Health Protection Branch approval was received to distribute125I-Fibrinogen Injection. Since that time over 30,000 vials of this drug have been prepared and used in the detection of venous thrombosis. Diagnosis of venous thrombosis with fibrinogen leg scanning depends on the incorporation of125I-Fibrinogen into the thrombus, which is then detected by measuring the consequent increase of overlying surface radioactivity using a small Na(TI) detector. The preparation of the drug relies on careful donor selection to minimize the chance of transmitting hepatitis. Careful separation of the fibrinogen is necessary to ensure that a high concentration of clottable protein is available for iodination. Fibrinogen having a clottable protein content in excess of 80% is iodinated using the ICl method. This product must have a consistent high quality. The control procedures used to examine the quality of each batch are described.

Recent Advances in the Toxicity of Heavy Metals - An Overview

Recent Advances in the Toxicity of Heavy Metals - An Overview Get access GEORGE C. BECKING GEORGE C. BECKING Environmental and Occupational Toxicology Division, Environmental Health Directorate, Health Protection Branch, Department of National Health and WelfareOttawa, Canada Search for other works by this author on: Oxford Academic PubMed Google Scholar Toxicological Sciences, Volume 1, Issue 5, September 1981, Pages 348–352, https://doi.org/10.1093/toxsci/1.5.348 Published: 01 September 1981

A glc method for quantitation of amygdalin and determination of relative potency of its hydrolytic enzyme(s) in certain foods or intestinal flora: B. Stavric and R. Klassen Bureau of Chemical Safety, Food Directorate, Health Protection Branch, Health & Welfare Canada, Ottawa, Ontario, KlA OL2, Canada

A glc method for quantitation of amygdalin and determination of relative potency of its hydrolytic enzyme(s) in certain foods or intestinal flora: B. Stavric and R. Klassen Bureau of Chemical Safety, Food Directorate, Health Protection Branch, Health & Welfare Canada, Ottawa, Ontario, KlA OL2, Canada

Response of y-1 adrenal cells to [formula omitted]: S. Stavric, J.I. Speirs, J. Konowalchuk and C. Park Bureau of Microbial Hazards, Food Directorate, Health Protection Branch, Health and Welfare Canada, Ottawa, KlA OL2, Canada

Response of y-1 adrenal cells to [formula omitted]: S. Stavric, J.I. Speirs, J. Konowalchuk and C. Park Bureau of Microbial Hazards, Food Directorate, Health Protection Branch, Health and Welfare Canada, Ottawa, KlA OL2, Canada

Microbial Standards for Cheese: The Canadian Approach

In Canada there are two jurisdictions concerned with and active in setting microbial standards to cheese. These are the Montreal Urban Community (MUC), a municipal government, and the Health Protection Branch of the Federal Department of National Health and Welfare (HPB). About 3 yr ago MUC insti tuted a regulation which placed a limit of one coliform per gram of cheese made from pasteurized milk. This has created considerable interest in Canada in the cheese industry and among the federal health authorities. The federal health people have over the years maintained a watch on the quality of cheese as well as on all other foods. On several occasions they have found samples of cheese that were far from satisfactory. The Food and Drug Act and Regulations of Canada has an omnibus clause that prohibits the sale of food that: a) has in or upon it any poisonous or harmful substance; b) is unfit for human consumption; c) consists in whole or in part of any filthy, putrid, disgusting, rotten, decomposed, or diseased animal or vegetable substance; d) is adulterated; or e) was manufactured, prepared, preserved, packaged, or stored under unsanitary conditions. However, such general regulations are not easy to present in court, and health officials have felt the need for more specific regulations that would afford better control of cheese. The MUC regulations triggered a reaction, and HPB responded with a comprehensive survey of the microbial content of cheese collected from retail outlets. From the data collected they estimated the levels

U-100 Insulin

IN FEBRUARY 1973, U-100 insulin (100 units/ml) was introduced in the United States by Eli Lilly & Company and a few months later by E. R. Squibb & Sons. The marketing of this strength of insulin was the culmination of many years of concern by the American Diabetes Association (ADA), the Food and Drug Administration, and the insulin manufacturers over medication errors that resulted from confusion between U-40 and U-80 insulins. Specifically, a few patients requiring U-40 insulin were inadvertently administering U-80, and marked hypoglycemia developed, while some requiring U-80 were using U-40 insulin with subsequent loss of control of the diabetes. Another hazard was the confusion frequently caused by the glass syringe marked with scales for both U-40 and U-80 insulins. The concentration of U-100 (100 units/ml) was agreed on by the ADA, the FDA, the Canadian regulatory agency (Health Protection Branch), and manufacturers of insulin in the United

Microbiological Standards for Cheese: Survey and Viewpoint of the Canadian Health Protection Branch

The Health Protection Branch, Health and Welfare Canada is considering proposals for microbiological standards for cheese. These proposals are based on a 2-year study (1974–1976) carried out by the Branch. The proposed standards per gram are: total coliforms m = 500, M = 1500, fecal coliforms m = 100, M = 500, and Staphylococcus aureus m = 100, M = 1000, for cheeses made from pasteurized milk; total coliforms m = 5000, M = 50,000, fecal coliforms m = 500, M = 1000, and S. aureus m = 1,000, M = 10,000 for cheeses made from heat treated or unpasteurized milk. The type of standard proposed will be based on a three-class acceptance plan as developed by the International Commission on Microbiological Specifications for Foods. Use of this plan in interpretation of the analytical results allows for the normal variation between analytical samples.

Food Safety in the Seventies

There is presently more concern about food safety than ever more, even though our foods are now much safer than they have ever been. As a regulatory agency, the Health Protection Branch wishes to ensure that all foods are safe for all Canadians all the time. The presence in foods of potentially hazardous chemicals, microorganisms, or products of microbial metabolism constitute some of the major hazards associated with foods. The acceptability to society of a given hazard (risk) and the cost to eliminate it must be considered when regulatory programs are developed.