Methods of analysis for toxic elements in food products. 3. Limit of determination of methods for assuring safety

To evaluate the suitability of the analytical methods used in determining food safety, a new metrological characteristic "MQS" is suggested. MQS is defined as the absolute minimum quantity in micrograms of a substance that can be determined in a test solution (solubilized test portion). MQS accounts for 2 factors: (a) the necessity for a reliable determination of ML (maximum permitted level, i.e., regulatory tolerance), and (b) the optimum quantity of test portion of a food product to be analyzed, and thus assists in evaluating the suitability of a method to assure food safety. The MQS of 8 toxic elements in any food are As, 3; Cd, 0.5; Cu, 20; Fe, 50; Hg, 0.2; Pb, 4; Sn, 200; Zn, 100 micrograms. To characterize the applicability of any given method, the specific minimum limit of determination, MQSM, must be established for each method. The method in question may be used to control food safety only if MQSM is less than MQS. MQSM values are given for the common polarographic and colorimetric methods for determining these elements.     

Malignant catarrhal fever in a swamp buffalo (Bubalus bubalis) calf in New Zealand

Malignant catarrhal fever was diagnosed in a newly imported swamp buffalo calf. This disease is prevalent in deer and cattle in New Zealand and causes sporadic losses in these species. The disease is recognised as a problem in buffaloes overseas and this paper records the first case in a swamp buffalo in New Zealand.     

Metabolic and anatomical adaptations of light‐bodied chicks to intermittent feeding

1. Chicks of a light‐bodied strain were deprived of food on alternate days from 15 to 46 d of age.

2. Hyperphagia, amounting to twice the intake of control birds early in the experiment, occurred on the repletion day.

3. Final body weight attained 80% of that of the controls.

4. Body fat concentration decreased at first but returned to that of controls after 3 weeks.

5. A consistent hyperlipaemia was observed after food deprivation or restoration.

6. There was a marked increase in the digestive enzymes found in the small intestine, but not in the pancreas during the repletion day.

7. These responses may be considered as mechanisms to reduce the physiological manifestations of starvation.     

Responses of immune and nonimmune adult rhesus macaques (Macaca mulatta) to adenovirus SV-20.

Adenovirus SV-20 (ASV-20) was inoculated subcutaneously into adult rhesus macaques (Macaca mulatta), and various immunologic parameters were studied. Similar changes were observed in macaques that had anti-ASV-20 serum-neutralizing antibodies prior to inoculation and in those lacking detectable antibodies. There were absolute decreases in numbers of peripheral blood lymphocytes (PBL), erythrocyte-rosetting lymphocytes, complement-receptor lymphocytes, and Fc-receptor lymphocytes. These changes were most significant (P less than 0.05) on postinoculation days (PID) 3 and 7. Mitogenic responsiveness to concanavalin A, phytohemagglutinin, and pokeweed mitogen in cultured PBL from immune and nonimmune macaques was depressed on PID 3, 7, and 14. Ultraviolet-inactivated ASV-20 caused moderate suppression of phytohemagglutinin-induced mitogenesis when viral particles and lectin were added simultaneously to PBL cultures. Plasma cortisol (hydrocortisone) values were not significantly altered following inoculation of ASV-20. High titers of anti-ASV-20 antibody developed by PID 7 in nonimmune macaques, and previously immune macaques showed a booster effect in the same time period. Antibody titers were still increased 120 days after inoculation. There was no clinical evidence of an adverse effect of ASV-20 infection in these macaques.     

Tissue reaction to Cysticercus bovis in the lung of artificially infected cattle

The tissue reaction to Cysticercus bovis in the lung of cattle with an experimental infection was an inflammatory rim originating in the immediate vicinity of the cysts. The cysts recovered at days 83 and 102 p.i. contained living cysticerci. The rim was composed either of a layer of high histiocytes organized in palisades (at day 83 p.i.), or a lyer of flat histiocytes (at day 102 p.i.). The outer layer of the rim consisted of fibroblasts, reticular cells and a different number of eosinophil- and neutrophil luekocytes. On the periphery, the rim was formed by granulation tissue infiltrated with lymphoplasmocytes. At the border between the layers of the inflammatory rim there were conspicuous foci of a necrotic appearance typical of a tissue reaction to C. bovis.