CS239035B1 - Method of controlling histamine in mackerel fish - Google Patents

Abstract

The essence of the histidine decarboxylation activity test consists in a double determination of histamine in the muscle of mackerel fish using the thin-layer chromatography method. The first determination is carried out immediately after thawing the fish, the second after 24 hours of storage of the same fish muscle at a temperature of 20 to 22 °C. In the case of increases in histamine in fish raw material stored for 24 hours at 20 to 22 °C above a concentration of 200 mg per kg of muscle, these are fish with a potential ability to produce histamine, unsuitable for further processing by smoking. The solution can be used primarily in the freezing and fishing industry, as well as in canneries processing fish raw material. Alternatively, the histidine decarboxylation activity test can also be used to investigate the health safety of animal feed.

Description

The invention relates to a method of histamine centre and lion fish macro. Up to now, the imported fish raw material was inspected immediately after its delivery to Czechoslovakia and then only for the final products - smoked fish.

When histamine was found, such fish, whether raw or smoked, were processed into fish meal. At that time, as is clear from the literature search and the patent class G01N 33/12, the commonly used methods do not allow identification of fish lots with the so-called " potential histamine-forming capacity; fish which only increase histamine in the process of smoking or improper storage.

Fish with a potential for the formation of histamine in the frozen state do not contain a higher level of histamine and do not show sensory changes against harmless fish, so they cannot be detected sensitively or analytically by histamine determination. The formation of histamine is linked to the presence of contaminating microflora, which under certain conditions during the smoking process, respectively. Inadequate storage, it produces the enzyme histidine decarboxylase, which decarboxylates the present histidine in fish muscle to toxic histamine. The decarboxylation proceeds according to the following scheme:

- CH - CH - COOH, - = CH - CH - NH _O + CO

II I ² - I ^{2 2} ι ² Ru ₂ NH _z MH '% of ^NH histamine histidine / 6-4-imidazolyl / «^ -4 TZ-aminopropionic imidazolyletylamin acid /

- 2 239 035

In fish species with potential histamine production the histamine content is increased from several units. tens of milligrams during smoking or storage up to toxic doses, i.e. several hundred milligrams per kg of fish muscle. The method of determining histidine decarboxylation activity (hereinafter HDA) allows to determine reliably the raw material that would produce a hygienically harmful product after technological processing before the smoking process. consists of two determinations of histamine in fish raw material by thin-layer chromatography. The HDA determination is carried out according to the following procedure: the fish muscle analyzed is homogenized immediately after thawing, the homogenate is divided into two parts, the first part determining the histamine content, the second part stored at 20 to 22 ° C for 24 hours. hours into the thermostat and thereafter the histamine content of the second portion is determined, with an increase in the histamine content of the second portion.

-i portions of more than 200 mg · kg, compared to the first portion, identify mackerel fish with a potential for histamine formation.

By practicing the invention, processing of mackerel fish with a potential for histamine formation, i.e., fish, from which a high-histamine hygienically objectionable foodstuff would be produced, can be avoided. Given that fish with a potential for histamine formation in the frozen state do not show high levels of histamine (they arise only in the smoking process) and are not otherwise hygienically or sensoryly defective, it is recommended to use such a raw material for processing marinations, respectively. to fish-based cans in tomato, when changes in the technological conditions of processing fish raw material will reduce the production of histamine by affecting the activity of histidine decarboxylation enzymes produced by contaminating microorganisms. Fish processed in this way with a potential histamine-forming capacity will provide a full-fledged food product without undesirable economic losses and endangering the health of consumers.

Example

The method of HDA determination is as follows: homogenise the muscle of the examined fish immediately after thawing and divide it into parts I and H. Take part I immediately for analysis, store part II at 20 to 22 ° C for 24 h. In a thermostat.

From Part I weigh 10 g of muscle, add 25 ml of distilled water and 5 ml of HCl, c / HCl / 6 mol. Homogenize the resulting mixture for 120 sec. in a laboratory mixer, filter and so collect the obtained filtrate in a refrigerator. In the same way, process the following dan and muscle II, stored 24 hours at 20 to 22 ° C in a thermostat - we obtain filtrate II. From the filtrate

I. and II. apply 10 ml of silufol to the chromatographic plate and at the same time apply a histamine standard corresponding to a concentration of 200 mg of histamine · kg of muscle (draft hygienic requirement for histamine content in mackerel fish), ie 0.5 µg of histamine. After the spots have dried, allow the plate to develop into an acetone-ammonia 95: 5 mixture. Once the face of the winding mixture reaches a distance of about 100 mm, remove the plate, dry. This is followed by spraying with a solution of ninhydrin in ethanol (ninhydrin) »0.2 g. 100 g. Spot visualization is performed by heating in a laboratory oven at 60 ° C for 300 sec. The histamine stain is red-violet. Histidine remains at the start. In the case of an increase in the histamine content of a fish raw material stored for 24 hours at 20-22 ° C above 200 mg of ₀ kg, it is a raw material with histidine decarboxylation activity.

239 033

The method can be used for in-process and initial control in all factories and plants processing or storing fish raw material.

Claims (1)

Object of the invention 239 035 A method for controlling histamine in mackerel fish, characterized in that the analyzed fish muscle is homogenized immediately after thawing, the homogenate is divided into two parts, the first part determining the histamine content and the second part stored at 20 to 22 ° C for a period of time. 24 hours into the thermostat and thereafter the histamine content of the second part is determined, with an increase in the histamine content of the second part of more than 200 mg · kg compared to the first part, to identify mackerel fish with potential histamine-forming capacity ·